The inflammatory and lung maturational effects of intra-amniotic exposure to endotoxin were assessed in fetal lambs. Five hours to 25 days after intra-amniotic injection of endotoxin, preterm lambs were delivered at 119-125 days gestation. Intra-amniotic endotoxin caused an inflammatory cell infiltration in amnion/chorion at 5 h, which persisted for 25 days. At 5-<em>15</em> h after endotoxin, amnion/chorion cytokine mRNAs increased [12- to 26-fold for <em>interleukin</em> (IL)-1beta, IL-6, and IL-8 mRNA and 3-fold for tumor necrosis factor-alpha mRNA]. At 1-2 days after endotoxin, lung cytokine mRNAs increased 6- to 49-fold. Endotoxin caused modest changes in peripheral white blood cell counts and no significant cytokine mRNA responses in fetal liver, placenta, or jejunum. Lung maturation, as characterized by increased lung volumes and alveolar saturated phosphatidylcholine, occurred at 7 days and persisted for 25 days after endotoxin. We conclude that exposure to a single dose of intra-amniotic endotoxin causes inflammation and increases in cytokine mRNA in amnion/chorion and the fetal lung before lung maturation, consistent with the hypothesis that proinflammatory cytokines signal lung maturation.

Although tumor necrosis factor (TNF) and <em>interleukin</em> 1 (IL-1) affect many cell functions, the molecular mechanisms of TNF and IL-1 action are not understood. Our present study shows that exposure of human FS-4 fibroblasts to TNF or IL-1 caused a rapid accumulation of intracellular cAMP and an increase in protein kinase activity. Intracellular cAMP levels peaked 3-5 min after the addition of TNF or IL-1 and returned to basal level by <em>15</em> min. Increased phosphorylation of histone HII-B protein was demonstrated with extracts prepared from TNF- or IL-1-treated cells, suggesting an increase in cAMP-dependent protein kinase activity. No evidence was obtained for protein kinase C activation in TNF-treated FS-4 cells. TNF, IL-1, and forskolin all stimulated <em>interleukin</em> 6 (IL-6) mRNA levels in FS-4 cells. The protein kinase inhibitor H-8, inhibiting preferentially cAMP-dependent kinase activity, reduced forskolin-stimulated IL-6 mRNA induction more strongly than TNF- or IL-1-driven IL-6 mRNA induction. These results suggest that activation of cAMP-dependent protein kinase by TNF and IL-1 is important in some actions of these cytokines. In addition, our data on IL-6 induction by TNF and IL-1 suggest that other, yet unidentified, signal transduction mechanisms contribute to TNF and IL-1 actions on gene expression in human fibroblasts.

Immunotherapy with high-dose <em>interleukin</em> (IL) 2 has been shown to successfully treat tumors in animal models and cause dramatic tumor regressions in some patients with metastatic melanoma, renal cell carcinoma, and non-Hodgkin's lymphoma. However, toxicity associated with IL-2 administration has compromised its widespread use in the clinic. IL-21 is a more recently discovered cytokine produced by activated CD4(+) T cells that shares significant sequence homology to IL-2, IL-4, and IL-<em>15</em>. Because IL-21 and IL-2 and their receptors share significant sequence similarities and both cytokines can stimulate T and natural killer (NK) cells, we sought to study whether IL-21, like IL-2, exhibits antitumor effects in vivo. In this study, we treated established s.c. tumor in mice by systemically administering plasmid DNA encoding murine IL-21 using a hydrodynamics-based gene delivery technique. Administration of IL-21 plasmid DNA resulted in high levels of circulating IL-21 in vivo. Treatment of tumor-bearing mice with IL-21 plasmid DNA significantly inhibited the growth of B16 melanoma and MCA205 fibrosarcoma in a dose-dependent manner without significant toxicity and increased the survival rate, compared with mice treated with control plasmid DNA. In vivo depletion of either CD4(+) or CD8(+) T cells did not affect IL-21-mediated antitumor activity. However, depletion of NK cells completely abolished IL-21-induced tumor inhibition. Consistent with this, the antitumor activity of IL-21 seemed to be mediated through enhanced cytolytic activity of NK cells. Our study suggests that IL-21 has significant antitumor activity and may have therapeutic potentials as an antitumor agent in the clinic.

Cytokine driven or "bystander" proliferation of T cells occurs in vivo independently of major histocompatibility complex-T cell receptor interactions. This process may be important for supporting T cell homeostasis and facilitating T cell responses to microbial antigens, and may involve the cytokine <em>interleukin</em> (IL)-<em>15</em>. In this study, we find that IL-<em>15</em>Ralpha-deficient (IL-<em>15</em>Ralpha(-/-)) mice fail to undergo poly I:C or IL-<em>15</em> driven bystander proliferation of CD8(+) T cells. Surprisingly, IL-<em>15</em>Ralpha(-/-) CD8(+) T cells proliferate in response to poly I:C when adoptively transferred into normal mice, and normal CD8(+) T cells fail to proliferate in IL-<em>15</em>Ralpha(-/-) mice. Normal mice reconstituted with IL-<em>15</em>Ralpha(-/-) bone marrow cells also fail to exhibit bystander responses. Thus, CD8(+) T cell independent IL-<em>15</em>Ralpha signals from radiation sensitive hematopoietic cells are likely required for bystander responses. Moreover, normal CD8(+) T cells proliferate in IL-<em>15</em>Ralpha(-/-) mice after treatment with IL-<em>15</em>. Therefore, IL-<em>15</em>Ralpha signals may mediate a positive feedback loop involving the further physiological production of IL-<em>15</em>. These findings provide new insights into how IL-<em>15</em>Ralpha supports memory phenotype CD8(+) T cell proliferation, and suggest novel mechanisms by which memory CD8(+) T cells are maintained in vivo.

Yersinia pestis, the etiologic agent of plague, delivers six Yersinia outer proteins (Yops) into host cells upon direct bacterial contact. One of these, YopM, is necessary for virulence in a mouse model of septicemic plague, but its pathogenic function is unknown. We report here the immune processes affected by YopM during infection. To test whether the innate or adaptive immune system is targeted by YopM, C57BL/6 (B6) and B6 SCID mice were infected with either the conditionally virulent Y. pestis KIM5 or a yopM deletion mutant and evaluated for bacterial growth in spleen and liver. Both B6 and SCID mice succumbed to infection with Y. pestis KIM5, whereas both mouse strains survived infection by the YopM(-) mutant. These data showed that YopM counteracts innate defenses present in SCID mice. The YopM(-) strain grew more slowly than the parent Y. pestis during the first 4 days of infection in both mouse strains, indicating an early pathogenic role for YopM. In B6 mice, populations of cells of the immune system were not differentially affected by the two Y. pestis strains, with one major exception: the parent Y. pestis KIM5 but not the YopM(-) mutant caused a significant global decrease in NK cell numbers (blood, spleen, and liver), beginning early in infection. NK cells and macrophages isolated early (day 2) from livers and spleens of mice infected with either Y. pestis strain contained comparable levels of cytokine mRNA: <em>interleukin</em> (IL)-1 beta, IL-12, IL-<em>15</em>, IL-18, and tumor necrosis factor alpha in macrophages and gamma interferon in NK cells. However, by day 4 postinfection, cells from mice infected with the parent Y. pestis expressed lower levels of these messages, while those from mice infected with the mutant retained strong expression. Significantly, mRNA for the IL-<em>15</em> receptor alpha chain was not expressed in NK cells from Y. pestis KIM5-infected mice as early as day 2 postinfection. These findings suggest that YopM interferes with innate immunity by causing depletion of NK cells, possibly by affecting the expression of IL-<em>15</em> receptor alpha and IL-<em>15</em>.

<em>Interleukin</em> <em>15</em> (IL-<em>15</em>) mRNA is expressed in a wide variety of tissue types. However, with the exception of some T cell lines, IL-<em>15</em> transcript expression has not been described in T cells. Herein we demonstrate that IL-<em>15</em> mRNA can be detected in freshly isolated normal T cells and T cell lines. Furthermore, its expression is 3- to 4-fold higher in human T cell lymphotropic virus type I (HTLV-I)-infected T cells. By using reporter constructs bearing the 5' regulatory region of the IL-<em>15</em> gene, we observed a positive correlation between HTLV-I Tax protein expression and IL-<em>15</em> promoter activity in HTLV-I-infected T cells. Additionally, by using a Jurkat T cell transfectant that expresses Tax under an inducible promoter, we demonstrated that the expression of IL-<em>15</em> mRNA increased 3-fold as Tax was expressed, suggesting that the Tax protein activates IL-<em>15</em> transcription. An NF-kappaB consensus sequence is located at the -75 and -65 region of the IL-<em>15</em> 5' regulatory region. Mutations in the NF-kappaB motif or deletion of this sequence abrogated the promoter activity in both HTLV-I-positive and Jurkat Tax-transfectant cells. These data represent evidence for trans-activation of the IL-<em>15</em> gene by the HTLV-I Tax protein through an NF-kappaB motif and suggest a potential role for IL-<em>15</em> in HTLV-I-associated diseases such as adult T cell leukemia and HTLV-I-associated myopathy/tropical spastic paraparesis.

Sixteen vitreous and paired serum samples from 13 patients with proliferative diabetic retinopathy, vitreous samples from seven cadaveric control subjects, and aqueous humor samples from <em>15</em> normal control subjects were assayed for the cytokines <em>interleukin</em>-1, tumor necrosis factor-alpha, <em>interleukin</em>-6, and interferon-gamma. <em>Interleukin</em>-6 was detected in <em>15</em> of 16 vitreous samples (94%) from diabetic patients, but it was not detected in any of the aqueous humor samples. Vitreous <em>interleukin</em>-6 levels positively correlated with ocular disease activity. <em>Interleukin</em>-1 was detected in seven of 16 vitreous samples (44%) and in four of ten aqueous humor samples (40%), whereas tumor necrosis factor-alpha and interferon-gamma were never detected in vitreous or aqueous fluid. Serum samples from diabetic patients and control subjects contained comparable low levels of <em>interleukin</em>-6. <em>Interleukin</em>-1, tumor necrosis factor-alpha, and interferon-gamma were not found in any of the sera. Because <em>interleukin</em>-6 can function as B-cell differentiation factor, this cytokine may have a role in immunoglobulin deposition in the ocular tissues and in the immunopathologic characteristics of proliferative retinopathy.

OBJECTIVE

The aim of this study was to document the effects of a new sedative agent, dexmedetomidine, on the mortality rate and inflammatory responses to endotoxin-induced shock in rats.

METHODS

Randomized laboratory study.

METHODS

University experimental laboratory.

METHODS

Fifty-seven male rats.

METHODS

The animals were randomly assigned to one of four groups. The endotoxemic group (n = 16) received intravenous Escherichia coli endotoxin (<em>15</em> mg/kg over 2 mins). The saline control group (n = 10) was given saline alone. The dexmedetomidine alone group (n = <em>15</em>) was treated identically to the control group but also received dexmedetomidine (infusion at 5 microg.kg(-1).hr(-1)) immediately after the injection of 0.9% saline. The dexmedetomidine-endotoxin group (n = 16) was treated identically to the endotoxemic group with the additional administration of dexmedetomidine (infusion at 5 microg.kg(-1).hr(-1)) immediately after endotoxin injection.

RESULTS

Hemodynamics and arterial blood gases were recorded and plasma cytokine concentrations measured during the observation. The mortality rate was assessed up to 8 hrs after endotoxin or saline injection. In addition, microscopic findings of lung tissue for each group were obtained at necropsy. Mortality rates 8 hrs after endotoxin injection were 94%, 10%, 0%, and 44% for the endotoxemic, saline control, dexmedetomidine alone, and dexmedetomidine-endotoxin groups, respectively. Hypotension and increases in plasma cytokine (tumor necrosis factor-alpha and interleukin-6) concentrations and infiltration of neutrophils in the airspace or vessel walls of the lungs were less in the dexmedetomidine-endotoxin group than in the endotoxemic group.

CONCLUSIONS

Dexmedetomidine reduced mortality rate and had an inhibitory effect on inflammatory response during endotoxemia. These findings suggest that dexmedetomidine administration may inhibit the inflammatory response.

OBJECTIVE

Epithelium derived <em>interleukin</em> (IL)-<em>15</em> signalling via IL-<em>15</em>Ralpha is critical for the development, activation, and survival of intraepithelial lymphocytes (IEL). We aimed to better understand the IL-<em>15</em> driven effects on IEL underlying mucosal damage and lymphomagenesis in coeliac disease (CD).

METHODS

Enterocytes, IEL, and lamina propria mononuclear cells (LPMC) were isolated from 46 patients with uncomplicated CD (25 untreated and 21 treated) and 22 controls. IL-<em>15</em> and IL-<em>15</em>Ralpha expression were determined by immunoblotting. Secretion of IL-<em>15</em>, interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), and granzyme B into cell culture supernatants was assessed by ELISA. The ability of IL-<em>15</em> to regulate IEL proliferation, perforin/granzyme dependent cytotoxicity, and apoptosis was tested by adding different combinations of IL-<em>15</em>, IL-<em>15</em> blocking antibody, or chloroquine to IEL cultured alone or with Caco-2 cells as target. IL-<em>15</em> mucosal levels were also determined by ELISA in five patients with complicated CD (two ulcerative jejunoileites, one refractory sprue, and two enteropathy associated T cell lymphomas) tested for T cell receptor gamma chain clonality.

RESULTS

IL-<em>15</em> was overexpressed in untreated CD enterocytes and LPMC, and in the mucosa of complicated CD patients and uncomplicated untreated CD patients, where its levels correlated with the degree of mucosal damage. Enterocytes from untreated, but not treated, CD patients and controls secreted IL-<em>15</em>. Untreated CD IEL, characterised by higher IL-<em>15</em>Ralpha expression, showed increased proliferation, production of IFN-gamma and TNF-alpha, and perforin/granzyme dependent cytotoxicity, and a decreased propensity to apoptosis in response to IL-<em>15</em>.

CONCLUSIONS

Our findings suggest that IL-<em>15</em> plays a crucial role in the generation of epithelial damage in active CD. Its promotion of IEL survival in CD may predispose to the emergence of T cell clonal proliferations. Blocking IL-<em>15</em>, by suppressing uncontrolled IEL activation and survival, has the potential to provide new therapeutic tools to prevent tissue damage and lymphomagenesis in CD.

Interferon-producing killer dendritic cells (IKDCs) are a recently described subset of CD11c(lo)B220(+) cells that share phenotypic and functional properties of DCs and natural killer (NK) cells (Chan, C.W., E. Crafton, H.N. Fan, J. Flook, K. Yoshimura, M. Skarica, D. Brockstedt, T.W. Dubensky, M.F. Stins, L.L. Lanier, et al. 2006. Nat. Med. 12:207-213; Taieb, J., N. Chaput, C. Menard, L. Apetoh, E. Ullrich, M. Bonmort, M. Pequignot, N. Casares, M. Terme, C. Flament, et al. 2006. Nat. Med. 12:214-219). IKDC development appears unusual in that cytokines using the <em>interleukin</em> (IL)-2 receptor beta (IL-2Rbeta) chain but not those using the common gamma chain (gamma(c)) are necessary for their generation. By directly comparing Rag2(-/-)gamma(c)(-/y), Rag2(-/-)IL-2Rbeta(-/-), Rag2(-/-)IL-<em>15</em>(-/-), and Rag2(-/-)IL-2(-/-) mice, we demonstrate that IKDC development parallels NK cell development in its strict IL-<em>15</em> dependence. Moreover, IKDCs uniformly express NK-specific Ncr-1 transcripts (encoding NKp46), whereas NKp46(+) cells are absent in Ncr1(gfp/+)gamma(c)(-/y) mice. Distinguishing features of IKDCs (CD11c(lo)B220(+)MHC-II(+)) were carefully examined on developing NK cells in the bone marrow and on peripheral NK cells. As B220 expression was heterogeneous, defining B220(lo) versus B220(hi) NK1.1(+) NK cells could be considered as arbitrary, and few phenotypic differences were noted between NK1.1(+) NK cells bearing different levels of B220. CD11c expression did not correlate with B220 or major histocompatibility complex (MHC) class II (MHC-II) expression, and most MHC-II(+) NK1.1(+) cells did not express B220 and were thus not IKDCs. Finally, CD11c, MHC-II, and B220 levels were up-regulated on NK1.1(+) cells upon activation in vitro or in vivo in a proliferation-dependent fashion. Our data suggest that the majority of CD11c(lo)B220(+) "IKDC-like" cells represent activated NK cells.

Experimental studies have shown that <em>interleukin</em>-6 induces all major acute-phase proteins in the liver, including C-reactive protein. In 50 patients with acute pancreatitis, the serum concentrations of <em>interleukin</em>-6 and C-reactive protein were determined daily during the first week of hospitalization. Patients were divided into three groups according to clinical criteria: mild pancreatitis (less than or equal to 1 complication; n = 25), severe pancreatitis (greater than or equal to 2 complications; n = <em>15</em>), and lethal outcome (n = 10). Patients with mild disease showed initially slightly elevated levels of <em>interleukin</em>-6 (22.0 +/- 9.8 U/mL) that decreased to low levels within 4 days (5.0 +/- 1.0 U/mL). In patients with severe pancreatitis, serum concentrations of <em>interleukin</em>-6 were initially clearly elevated (35.0 +/- 7.5 U/mL) and remained slightly elevated until day 7 (13.0 +/- 2.0 U/mL). Patients with lethal outcome had markedly elevated initial <em>interleukin</em>-6 concentrations (61.0 +/- <em>15</em>.0 U/mL) that decreased but were still elevated at day 7 (26.0 +/- 2.5 U/mL). In all three groups, C-reactive protein concentrations followed the course of <em>interleukin</em>-6 concentrations by 1 day. There was a positive correlation between maximal <em>interleukin</em> 6 concentrations and maximal increases in the serum concentrations of C-reactive protein (r = 0.66). At days 1 and 2, increased (greater than <em>15</em> U/mL) <em>interleukin</em>-6 concentrations (positive predictive value, 91%; negative predictive value, 82%) predicted a severe or lethal course of the disease more accurately than elevated [greater than 0.10 g/L (greater than 10 mg/dL)] C-reactive protein concentrations (positive predictive value, 67%; negative predictive value, 79%). In conclusion, elevated serum concentrations of <em>interleukin</em>-6 followed by increased levels of C-reactive protein reflect the severity of acute pancreatitis.

Autosomal dominant deficiency of signal transducer and activator of transcription 3 (STAT3) is the main genetic etiology of hyper-immunoglobulin (Ig) E syndrome. We documented the molecular, cellular, and clinical features of 60 patients with heterozygous STAT3 mutations from 47 kindreds followed in France. We identified 11 known and 13 new mutations of STAT3. Low levels of <em>interleukin</em> (IL)-6-dependent phosphorylation and nuclear translocation (or accumulation) of STAT3 were observed in Epstein-Barr virus-transformed B lymphocytes (EBV-B cells) from all STAT3-deficient patients tested. The immunologic phenotype was characterized by high serum IgE levels (96% of the patients), memory B-cell lymphopenia (94.5%), and hypereosinophilia (80%). A low proportion of IL-17A-producing circulating T cells was found in 14 of the <em>15</em> patients tested. Mucocutaneous infections were the most frequent, typically caused by Staphylococcus aureus (all patients) and Candida albicans (85%). Up to 90% of the patients had pneumonia, mostly caused by Staph. aureus (31%) or Streptococcus pneumoniae (30%). Recurrent pneumonia was associated with secondary bronchiectasis and pneumatocele (67%), as well as secondary aspergillosis (22%). Up to 92% of the patients had dermatitis and connective tissue abnormalities, with facial dysmorphism (95%), retention of decidual teeth (65%), osteopenia (50%), and hyperextensibility (50%). Four patients developed non-Hodgkin lymphoma. The clinical outcome was favorable, with 56 patients, including 43 adults, still alive at the end of study (mean age, 21 yr; range, 1 mo to 46 yr). Only 4 patients died, 3 from severe bacterial infection (aged 1, <em>15</em>, and 29 yr, respectively). Antibiotic prophylaxis (90% of patients), antifungal prophylaxis (50%), and IgG infusions (53%) improved patient health, as demonstrated by the large decrease in pneumonia recurrence. Overall, the prognosis of STAT3 deficiency may be considered good, provided that multiple prophylactic measures, including IgG infusions, are implemented.

<em>Interleukin</em>-1 has been postulated as a signal for the initiation of preterm labor and delivery. <em>Interleukin</em>-1 is produced by human decidua, stimulates prostaglandin production by intrauterine tissues, and is present in the amniotic fluid of women with preterm labor and intraamniotic infection. The purpose of these studies was to determine whether <em>interleukin</em>-1 could induce parturition in an animal species. Timed-pregnant C3H/HeJ inbred mice (n = 24) (genetically endotoxin resistant) were randomized to receive either recombinant human <em>interleukin</em>-1 or sterile phosphate-buffered saline solution between days <em>15</em> and 17 of gestation (normal length of pregnancy, 20 to 21 days). Three consecutive subcutaneous injections of <em>interleukin</em>-1 or phosphate-buffered saline solution were administered within 6 hours. Examinations of the animals were performed by blinded observers. Parturition occurred within 24 hours in all of the <em>interleukin</em>-1-treated mice and in none of the control group. Vaginal bleeding was first noted 4 hours after the first <em>interleukin</em>-1 injection, and delivery began within 12 hours after the last <em>interleukin</em>-1 injection. Premature delivery occurred in all <em>interleukin</em>-1-injected mice. Laparotomy revealed that there were no remaining fetuses in utero. All mice in the control group delivered spontaneously between days 20 and 22. We conclude that systemic administration of <em>interleukin</em>-1 induces preterm labor and delivery in mice.

BACKGROUND

Chronic heart failure is one of a number of disorders associated with the development of a wasting syndrome. The precise mechanisms of this remain unknown, but previous studies have suggested a role for immune and neurohormonal factors.

METHODS

We aimed to investigate in detail the differences in body composition (dual X-ray absorptiometry) and the relationship to candidate biochemical factors of the immune, neurohormonal and metabolic systems in <em>15</em> healthy controls, 36 stable non-cachectic and 18 cachectic patients with chronic heart failure.

RESULTS

Non-cachectic patients showed reduced leg lean tissue (-9.1%, P<0.01) compared to controls. Cachectic patients had significantly reduced lean (-21.0% vs controls, -19.9% vs non-cachectics), fat (-33.0% vs controls, -37. 0% vs non-cachectics) and bone tissue (-17.5% vs controls, -<em>15</em>.9% vs non-cachectics) (all P<0.0001). Cachectic patients showed a significantly increased cortisol/dehydroepiandrosterone ratio (+203% vs controls, P<0.0001; +89% vs non-cachectics, P=0.0011) and increased cytokine levels (TNF-alpha, soluble TNF-receptor 1, interleukin-6). The levels of catabolic hormones and cytokines correlated significantly with reduced muscle and fat tissue content and reduced bone mass.

CONCLUSIONS

Peripheral loss of muscle tissue is a general finding in chronic heart failure. The wasting in cardiac cachexia affects all tissue compartments and is significantly related to neurohormonal and immunological abnormalities.

OBJECTIVE

<em>Interleukin</em> (IL)-<em>15</em> exerts functional effects on lymphocytes similar to those of IL-2. IL-<em>15</em> is expressed by nonlymphoid cells and may integrate these cells into classical immune responses. The aim of this study was to characterize the expression of IL-<em>15</em> by intestinal epithelial cells and determine the functional roles of IL-<em>15</em> within the mucosal immune system.

METHODS

Rat IL-<em>15</em> was cloned from a rat jejunal library. Expression of IL-<em>15</em> in rat and human intestinal epithelial cells was assessed by Northern and Western blotting. Tyrosine kinase activation in response to IL-<em>15</em> in intestinal epithelial cells was determined by immunoprecipitation.

RESULTS

Rat and human intestinal epithelial cells express IL-<em>15</em> messenger RNA. IL-<em>15</em> activates Stat3 and stimulates the proliferation of intestinal epithelial cells. The relevance of the observations for intestinal epithelial cell function in vivo was supported by the demonstration of transcripts for IL-<em>15</em> in primary human intestinal epithelial cells.

CONCLUSIONS

IL-<em>15</em> is expressed by intestinal epithelial cells function. These experiments suggest that IL-<em>15</em> is an important mediator that could integrate intestinal epithelial cell function with the intestinal immune system.

<em>Interleukin</em>-<em>15</em> shares many biological activities with IL-2 and signals through the IL-2 receptor beta and gamma chains. However, IL-<em>15</em> and IL-2 differ in their controls of expression and secretion, their range of target cells and their functional activities. These dissimilarities may include differential effects on apoptosis. For example, IL-2 induces or inhibits T-cell apoptosis in vitro, depending on T-cell activation, whereas IL-<em>15</em> inhibits cytokine deprivation-induced apoptosis in activated T cells. Studying whether and how IL-<em>15</em> modulates distinct apoptosis pathways, we show here that apoptosis induced by anti-Fas, anti-CD3, dexamethasone, and/or anti-IgM in activated human T and B cells in vitro is inhibited by IL-<em>15</em> in a manner dependent on RNA synthesis. In vivo, anti-Fas-induced lethal multisystem apoptosis in mice is suppressed by a novel IL-<em>15</em>-IgG2b fusion protein. Only IL-<em>15</em>, but not IL-2, completely protected from lethal hepatic failure. Thus, IL-<em>15</em> is a potent, general inhibitor of apoptosis in vitro and in vivo with intriguing therapeutic potential.

A patient with primary plasma cell leukemia resistant to chemotherapy was treated for 2 months with daily intravenous injections of anti-<em>interleukin</em>-6 (IL-6) monoclonal antibodies (MoAbs). The patient's clinical status improved throughout the treatment and no major side effects were observed. Serial monitoring showed blockage of the myeloma cell proliferation in the bone marrow (from 4.5% to 0% myeloma cells in the S-phase in vivo) as well as reduction in the serum calcium, serum monoclonal IgG, and the serum C-reactive protein levels. The serum calcium and serum monoclonal IgG corrected by approximately 30%, whereas the C-reactive protein corrected to undetectable levels during treatment. No major side effects developed, although both platelet and circulating neutrophil counts decreased during anti-IL-6 therapy. A transient immunization was detected <em>15</em> days after the initiation of the treatment, which could explain the recovery of myeloma cell proliferation after 2 months of treatment (2% myeloma cells in the S phase). In conclusion, this first anti-IL-6 clinical trial demonstrated the feasibility of injecting anti-IL-6 MoAbs, and also a transient tumor cytostasis and a reduction in IL-6-related toxicities. It gave insight into the major biologic activities of IL-6 in vivo and may serve as a basis for further development of anti-IL-6 therapy in myeloma and other IL-6-related diseases.

In previous studies, we showed that blood monocyte elaboration of <em>interleukin</em> 1 (IL-1), a known stimulator of bone resorption, was higher in osteoporotic patients with rapid bone turnover than in those with slow turnover and in nonosteoporotic subjects. Since an acceleration of bone loss following menopause contributes to the risk of osteoporosis in women, we have studied the effects of menopause and ovarian steroid treatment on IL-1 release by monocytes obtained from nonosteoporotic and osteoporotic women. IL-1 activity in the monocyte culture medium derived from untreated postmenopausal women (nonosteoporotic and osteoporotic) was higher than in the medium derived from either untreated premenopausal or estrogen/progesterone-treated postmenopausal women. A significant negative correlation was found between IL-1 and years since menopause in both the healthy (r = -0.75; P less than 0.005) and the osteoporotic (r = -0.61; P less than 0.01) untreated postmenopausal women. The difference between the two slopes was significant at P less than 0.05. Premenopausal IL-1 levels were achieved within 8 years of menopause in the nonosteoporotic, but not in the osteoporotic, subjects in whom increases were evident as long as <em>15</em> years after menopause. IL-1 also correlated inversely with vertebral mineral density (r = -0.37; P less than 0.05), as measured by quantitative computed tomography. In prospective studies, treatment with estrogen/progesterone for 1 month caused a substantial highly significant decrease in IL-1 activity in each of three nonosteoporotic and five osteoporotic women, confirming the apparent effect of hormone therapy observed in the cross-sectional analysis. Although a cause-effect relationship has not been established, it is our hypothesis, based on these data, that alterations in IL-1 production may underlie the postmenopausal acceleration in bone loss and its inhibition by ovarian steroids. Persistent elevation of IL-1 secretion appears to be a feature of postmenopausal osteoporosis.

Background: Tocilizumab, a monoclonal antibody directed against the interleukin-6 receptor, has been proposed to mitigate the cytokine storm syndrome associated with severe COVID-19. We aimed to investigate the association between tocilizumab exposure and hospital-related mortality among patients requiring intensive care unit (ICU) support for COVID-19.

Methods: We did a retrospective observational cohort study at 13 hospitals within the Hackensack Meridian Health network (NJ, USA). We included patients (aged ≥18 years) with laboratory-confirmed COVID-19 who needed support in the ICU. We obtained data from a prospective observational database and compared outcomes in patients who received tocilizumab with those who did not. We applied a multivariable Cox model with propensity score matching to reduce confounding effects. The primary endpoint was hospital-related mortality. The prospective observational database is registered on ClinicalTrials.gov, NCT04347993.

Findings: Between March 1 and April 22, 2020, 764 patients with COVID-19 required support in the ICU, of whom 210 (27%) received tocilizumab. Factors associated with receiving tocilizumab were patients' age, gender, renal function, and treatment location. 630 patients were included in the propensity score-matched population, of whom 210 received tocilizumab and 420 did not receive tocilizumab. 358 (57%) of 630 patients died, 102 (49%) who received tocilizumab and 256 (61%) who did not receive tocilizumab. Overall median survival from time of admission was not reached (95% CI 23 days-not reached) among patients receiving tocilizumab and was 19 days (16-26) for those who did not receive tocilizumab (hazard ratio [HR] 0·71, 95% CI 0·56-0·89; p=0·0027). In the primary multivariable Cox regression analysis with propensity matching, an association was noted between receiving tocilizumab and decreased hospital-related mortality (HR 0·64, 95% CI 0·47-0·87; p=0·0040). Similar associations with tocilizumab were noted among subgroups requiring mechanical ventilatory support and with baseline C-reactive protein of 15 mg/dL or higher.

Interpretation: In this observational study, patients with COVID-19 requiring ICU support who received tocilizumab had reduced mortality. Results of ongoing randomised controlled trials are awaited.

Funding: None.

We show that co-expression of <em>interleukin</em> <em>15</em> (IL-<em>15</em>) and IL-<em>15</em> receptor alpha (IL-<em>15</em>Ralpha) in the same cell allows for the intracellular interaction of the two proteins early after translation, resulting in increased stability and secretion of both molecules as a complex. In the absence of co-expressed IL-<em>15</em>Ralpha, a large portion of the produced IL-<em>15</em> is rapidly degraded immediately after synthesis. Co-injection into mice of IL-<em>15</em> and IL-<em>15</em>Ralpha expression plasmids led to significantly increased levels of the cytokine in serum as well as increased biological activity of IL-<em>15</em>. Examination of natural killer cells and T lymphocytes in mouse organs showed a great expansion of both cell types in the lung, liver, and spleen. The presence of IL-<em>15</em>Ralpha also increased the number of CD44(high) memory cells with effector phenotype (CD44(high)CD62L-). Thus, mutual stabilization of IL-<em>15</em> and IL-<em>15</em>Ralpha leads to remarkable increases in production, stability, and tissue availability of bioactive IL-<em>15</em> in vivo. The in vivo data show that the most potent form of IL-<em>15</em> is as part of a complex with its receptor alpha either on the surface of the producing cells or as a soluble extracellular complex. These results explain the reason for coordinate expression of IL-<em>15</em> and IL-<em>15</em>Ralpha in the same cell and suggest that the IL-<em>15</em>Ralpha is part of the active IL-<em>15</em> cytokine rather than part of the receptor.

In humans, <em>interleukin</em>-1beta (IL-1beta) has been suggested as an essential cytokine for developing IL-17- or IL-17A-producing CD4(+) T helper 17 (Th17) cells. However, little is known about the relationship of IL-1 receptor expression and Th17 cell differentiation. We report here the presence of 2 distinct CD4(+) T-cell populations with and without expression of IL-1RI that correlates with the capacity to produce IL-17 in naive and memory CD4(+) T cells of human peripheral blood. IL-1RI(+) memory CD4(+) T cells had increased gene expression of IL17, RORC, and IRF4 even before T-cell receptor triggering, indicating that the effect of IL-1beta is programmed in these cells via IL-1RI. Although CD4(+) T cells from umbilical cord blood did not express IL-1RI, the cytokines IL-7, IL-<em>15</em>, and transforming growth factor-beta (TGF-beta) up-regulated IL-1RI expression on naive CD4(+) T cells, suggesting that IL-1RI(+) naive CD4(+) T cells develop in periphery. Furthermore, IL-17 production from the cytokine-treated naive CD4(+) T cells was induced by IL-1beta and this induction was blocked by IL-1R antagonist. These results indicate that human Th17 cell differentiation is regulated via differential expression of IL-1RI, which is controlled by IL-7 and IL-<em>15</em>.

In both plants and animals, nucleotide-binding (NB) domain and leucine-rich repeat (LRR)-containing proteins (NLR) function as sensors of pathogen-derived molecules and trigger immune responses. Although NLR resistance (R) proteins were first reported as plant immune receptors more than <em>15</em> years ago, how these proteins activate downstream defense responses is still unclear. Here we report that the Toll-like/<em>interleukin</em>-1 receptor (TIR)-NB-LRR R protein, suppressor of npr1-1, constitutive 1 (SNC1) functions through its associated protein, Topless-related 1 (TPR1). Knocking out TPR1 and its close homologs compromises immunity mediated by SNC1 and several other TIR-NB-LRR-type R proteins, whereas overexpression of TPR1 constitutively activates SNC1-mediated immune responses. TPR1 functions as a transcriptional corepressor and associates with histone deacetylase 19 in vivo. Among the target genes of TPR1 are Defense no Death 1 (DND1) and Defense no Death 2 (DND2), two known negative regulators of immunity that are repressed during pathogen infection, suggesting that TPR1 activates R protein-mediated immune responses through repression of negative regulators.

Like human gliomas, the rat 9L gliosarcoma secretes the immunosuppressive transforming growth factor beta (TGF-beta). Using the 9L model, we tested our hypothesis that genetic modification of glioma cells to block TGF-beta expression may enhance their immunogenicity and make them more suitable for active tumor immunotherapy. Subcutaneous immunizations of tumor-bearing animals with 9L cells genetically modified to inhibit TGF-beta expression with an antisense plasmid vector resulted in a significantly higher number of animals surviving for 12 weeks (11/11, 100%) compared to immunizations with control vector-modified 9L cells (2/<em>15</em>, 13%) or 9L cells transduced with an <em>interleukin</em> 2 retroviral vector (3/10, 30%) (P < 0.001 for both comparisons). Histologic evaluation of implantation sites 12 weeks after treatment revealed no evidence of residual tumor. In vitro tumor cytotoxicity assays with lymph node effector cells revealed a 3- to 4-fold increase in lytic activity for the animals immunized with TGF-beta antisense-modified tumor cells compared to immunizations with control vector or <em>interleukin</em> 2 gene-modified tumor cells. These results indicate that inhibition of TGF-beta expression significantly enhances tumor-cell immunogenicity and supports future clinical evaluation of TGF-beta antisense gene therapy for TGF-beta-expressing tumors.

Patients with glucocorticoid excess develop central obesity, yet in simple obesity, circulating glucocorticoid levels are normal. We have suggested that the increased activity and expression of the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) generating active cortisol from cortisone within adipose tissue may be crucial in the pathogenesis of obesity. In this study primary cultures of human hepatocytes and adipose stromal cells (ASC) were used as in vitro models to investigate the tissue-specific regulation of 11betaHSD1 expression and activity. Treatment with tumor necrosis factor-alpha (TNFalpha) caused a dose-dependent increase in 11betaHSD1 activity in primary cultures of both sc [1743.1 +/- 10<em>15</em>.4% (TNFalpha, 10 ng/ml); P < 0.05 vs. control (100%)] and omental [375.8 +/- 57.0% (TNFalpha, 10 ng/ml); P < 0.01 vs. control (100%)] ASC, but had no effect on activity in human hepatocytes [90.2 +/- 2.8% (TNFalpha, 10 ng/ml); P = NS vs. control (100%)]. Insulin-like growth factor I (IGF-I) caused a dose-dependent inhibition of 11betaHSD1 activity in sc [49.7 +/- <em>15</em>.0% (IGF-I, 100 ng/ml]; P < 0.05 vs. control (100%)] and omental [71.6 +/- 7.5 (IGF-I, 100 ng/ml); P < 0.01 vs. control (100%)] stromal cells, but not in human hepatocytes [101.8 +/- <em>15</em>.7% (IGF-I, 100 ng/ml); P = NS vs. control (100%)]. Leptin treatment did not alter 11betaHSD1 activity in human hepatocytes, but increased activity in omental ASC [135.8 +/- 14.1% (leptin, 100 ng/ml); P = 0.08 vs. control (100%)]. Treatment with <em>interleukin</em>-1beta induced 11betaHSD1 activity and expression in sc and omental ASC in a time- and dose-dependent manner. <em>15</em>-Deoxy-12,14-PGJ2, the putative endogenous ligand of the orphan nuclear receptor peroxisome proliferator-gamma, significantly increased 11betaHSD1 activity in omental cells [179.7 +/- 29.6% (1 microM); P < 0.05 vs. control (100%)] and sc [185.3 +/- 12.6% (1 microM); P < 0.01 vs. control (100%)] ASC, and it is possible that expression of this ligand may ensure continued cortisol generation to permit adipocyte differentiation. Protease inhibitors used in the treatment of human immunodeficiency virus infection are known to cause a lipodystrophic syndrome and central obesity, but saquinavir, indinavir, and neflinavir caused a dose-dependent inhibition of 11betaHSD1 activity in primary cultures of human omental ASC. 11betaHSD1 expression is increased in human adipose tissue by TNFalpha, <em>interleukin</em>-1beta, leptin, and orphan nuclear receptor peroxisome proliferator-gamma agonists, but is inhibited by IGF-I. This autocrine and/or paracrine regulation is tissue specific and explains recent clinical data and animal studies evaluating cortisol metabolism in obesity. Tissue-specific 11betaHSD1 regulation offers the potential for selective enzyme inhibition within adipose tissue as a novel therapy for visceral obesity.