Rheumatoid arthritis is characterised by persistent synovitis, systemic inflammation, and autoantibodies (particularly to rheumatoid factor and citrullinated peptide). 50% of the risk for development of rheumatoid arthritis is attributable to genetic factors. Smoking is the main environmental risk. In industrialised countries, rheumatoid arthritis affects 0·5-1·0% of adults, with 5-50 per 100 000 new cases annually. The disorder is most typical in women and elderly people. Uncontrolled active rheumatoid arthritis causes joint damage, disability, decreased quality of life, and cardiovascular and other comorbidities. Disease-modifying antirheumatic drugs (DMARDs), the key therapeutic agents, reduce synovitis and systemic inflammation and improve function. The leading DMARD is methotrexate, which can be combined with other drugs of this type. Biological agents are used when arthritis is uncontrolled or toxic effects arise with DMARDs. Tumour necrosis factor inhibitors were the first biological agents, followed by abatacept, rituximab, and tocilizumab. Infections and high costs restrict prescription of biological agents. Long-term remission induced by intensive, short-term treatment selected by biomarker profiles is the ultimate goal.

We have attempted to design classification criteria for adult Still's disease by analyzing the data obtained through a multicenter survey of 90 Japanese patients with this disease and of 267 control patients. The proposed criteria consisted of fever, arthralgia, typical rash, and leukocytosis as major, and sore throat, lymphadenopathy and/or splenomegaly, liver dysfunction, and the absence of rheumatoid factor and antinuclear antibody as minor criteria. Requiring 5 or more criteria including 2 or more major criteria yielded 96.2% sensitivity and 92.1% specificity. However, an exclusion process will be needed for an accurate classification, since this disease is relatively rare.

Interleukin (IL)-6 is a pleiotropic cytokine that has important roles in the regulation of the immune response, inflammation, and hematopoiesis. Disruption of IL-6 regulation might, however, affect the immune response and consequently induce immune-mediated inflammatory diseases such as rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease, and Crohn's disease. Overproduction of IL-6 also contributes, through its roles as a growth factor or an antiapoptotic factor, to the development of malignant diseases such as multiple myeloma and renal cancer. Progress in the study of IL-6 has increased our understanding of the pathological roles of this cytokine in these diseases and provided key evidence that antagonizing its activities can be used as a therapeutic strategy. The application of molecular biology techniques to design monoclonal antibodies as therapeutic agents has made it possible to regulate the IL-6 signal to successfully treat diseases that have so far proved refractory to conventional therapies. Blocking IL-6 actions by use of a humanized antibody, tocilizumab, which targets the IL-6 receptor, has been proven to be therapeutically effective for rheumatoid arthritis, systemic juvenile idiopathic arthritis, Castleman disease and Crohn's disease. In this review, we discuss a paradigm of IL-6 from basic science to clinical use.

BACKGROUND

Anakinra treatment has been reported to be effective in some patients with systemic-onset juvenile idiopathic arthritis (SoJIA) or adult-onset Still disease (AoSD).

OBJECTIVE

To assess the efficacy and the safety of anakinra treatment in SoJIA and AoSD.

METHODS

SoJIA and AoSD patients were treated with anakinra (1-2 mg/kg/day in children, 100 mg/day in adults); we analysed its effect on fever, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, numbers of swollen and tender joints, the assessment of disease activity (by physician and parent/patient) and pain (by parent/patient), and American College of Rheumatology (ACR) pediatric core set criteria for JIA activity.

RESULTS

A total of 35 patients were included, 20 with SoJIA and 15 with AoSD. Their mean age (range) at the onset of treatment was 12.4 (3-23) and 38.1 (22-62) years, respectively; disease duration was 7.0 (1-16) and 7.8 (2-27) years, respectively. Active arthritis was present in all cases but one. Of the 20 SoJIA patients, 5 achieved ACR 50% improvement in symptoms (ACR50) response criteria at 6 months. Steroid dose had been decreased by 15% to 78% in 10 cases. A total of 11 of the 15 AoSD patients achieved at least a 50% improvement for all disease markers (mean follow-up: 17.5 (11-27) months). Steroids had been stopped in two cases and the dose was decreased by 45% to 95% in 12 patients. Two patients stopped anakinra due to severe skin reaction, and two patients due to infection: one visceral leishmaniasis and one varicella.

CONCLUSIONS

Anakinra was effective in most AoSD patients, but less than half SoJIA patients achieved a marked and sustained improvement.

BACKGROUND

Adult onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown aetiology that is responsible for a significant proportion of cases of fever of unknown origin and can also have serious musculoskeletal sequelae.

OBJECTIVE

To assess and synthesise the evidence for optimal diagnosis and management of AOSD.

METHODS

The key terms, adult onset Still's disease, AOSD, adult Still's disease, ASD, Still's disease were used to search Medline (1966-2005) and PubMed (1966-2005) for all available articles in the English language. Clinically relevant articles were subsequently selected. Bibliographies, textbooks, and websites of recent rheumatology conferences were also assessed.

RESULTS

Data on diagnosis and treatment of AOSD are limited in the medical literature and consist mainly of case reports, small series, and modest scale retrospective studies. Diagnosis is clinical and requires exclusion of infectious, neoplastic, and other autoimmune diseases. Laboratory tests are non-specific and reflect heightened immunological activity. Treatment comprises non-steroidal anti-inflammatory drugs, corticosteroids, immunosuppressive drugs (methotrexate, leflunomide, gold, azathioprine, cyclosporin A, cyclophosphamide), and intravenous gammaglobulin. The recent successful application of biological agents (anti-tumour necrosis factor, anti-interleukin (IL)1, anti-IL6), often in combination with traditional immunosuppressive drugs, has been very promising.

CONCLUSIONS

AOSD often poses a diagnostic and therapeutic challenge and clinical guidelines are lacking. The emergence of validated diagnostic criteria, discovery of better serological markers, and the application of new biological agents may all provide the clinician with significant tools for the diagnosis and management of this complex systemic disorder.

OBJECTIVE

To assess the efficacy of anakinra treatment in patients with adult-onset Still's disease (AOSD) that is refractory to corticosteroids, methotrexate (MTX), and etanercept.

METHODS

Four patients with AOSD were treated with prednisone and MTX and 2 patients were also treated with etanercept for worsening symptoms and indicators of systemic inflammation. White blood cells (WBCs), C-reactive protein (CRP) levels and/or erythrocyte sedimentation rate, and ferritin levels were measured and, in 1 patient, serum creatinine levels were determined. Treatment with anakinra at 100 mg/day was initiated.

RESULTS

The index patient's disease was refractory to treatment with prednisone (30 mg/day) and MTX, with spiking fevers, rash, synovitis, a serum ferritin level of 8,400 ng/ml (normal </=200), and a CRP level of 86 mg/liter (normal <8). Levels of interleukin-1beta (IL-1beta), IL-1alpha, IL-6, IL-1 receptor antagonist, and IL-18 were elevated. Just prior to anakinra treatment, the WBC count was 14,600/mm(3), the CRP level was 86 mg/liter, and the ferritin level was 573 ng/ml, with daily spiking fevers to 104 degrees F, rash, and swollen joints. Within hours of the first injection, the patient was afebrile and asymptomatic; within days, the WBC count, ferritin level, and CRP level decreased into the normal range. On 2 occasions, anakinra was withheld. Within a few days, the WBC count rose to >20,000/mm(3) with prominent neutrophilia, the CRP level rose to >200 mg/liter, and the ferritin level rose to >3,000 ng/ml. Upon restarting anakinra, the patient became afebrile, the WBC count fell to 8,000/mm(3), the CRP level fell to <3 mg/liter, and the ferritin level fell to <300 ng/ml. Three additional patients with refractory AOSD who experienced rapid reductions in fever, symptoms, and markers of inflammation when treated with anakinra are reported.

CONCLUSIONS

Refractory AOSD appears to be IL-1-mediated since anakinra decreases hematologic, biochemical, and cytokine markers and also produces rapid reductions in systemic and local inflammation. Reported efficacy of tumor necrosis factor-blocking therapies in AOSD may be due to a reduction in IL-1.

First described in 1971, adult-onset Still's disease (AOSD) is a rare multisystemic disorder considered as a complex (multigenic) autoinflammatory syndrome. A genetic background would confer susceptibility to the development of autoinflammatory reactions to environmental triggers. Macrophage and neutrophil activation is a hallmark of AOSD which can lead to a reactive hemophagocytic lymphohistiocytosis. As in the latter disease, the cytotoxic function of natural killer cells is decreased in patients with active AOSD. IL-18 and IL-1β, two proinflammatory cytokines processed through the inflammasome machinery, are key factors in the pathogenesis of AOSD; they cause IL-6 and Th1 cytokine secretion as well as NK cell dysregulation leading to macrophage activation. The clinico-biological picture of AOSD usually includes high spiking fever with joint symptoms, evanescent skin rash, sore throat, striking neutrophilic leukocytosis, hyperferritinemia with collapsed glycosylated ferritin (<20%), and abnormal liver function tests. According to the clinical presentation of the disease at diagnosis, two AOSD phenotypes may be distinguished: i) a highly symptomatic, systemic and feverish one, which would evolve into a systemic (mono- or polycyclic) pattern; ii) a more indolent one with arthritis in the foreground and poor systemic symptomatology, which would evolve into a chronic articular pattern. Steroid- and methotrexate-refractory AOSD cases benefit now from recent insights into autoinflammatory disorders: anakinra seems to be an efficient, well tolerated, steroid-sparing treatment in systemic patterns; tocilizumab seems efficient in AOSD with active arthritis and systemic symptoms while TNFα-blockers could be interesting in chronic polyarticular refractory AOSD.

BACKGROUND

Over the last few years, accumulating data have implicated a role for ferritin as a signaling molecule and direct mediator of the immune system. Hyperferritinemia is associated with a multitude of clinical conditions and with worse prognosis in critically ill patients.

CONCLUSIONS

There are four uncommon medical conditions characterized by high levels of ferritin, namely the macrophage activation syndrome (MAS), adult onset Still's disease (AOSD), catastrophic antiphospholipid syndrome (cAPS) and septic shock, that share a similar clinical and laboratory features, and also respond to similar treatments, suggesting a common pathogenic mechanism. Ferritin is known to be a pro-inflammatory mediator inducing expression of pro-inflammatory molecules, yet it has opposing actions as a pro-inflammatory and as an immunosuppressant. We propose that the exceptionally high ferritin levels observed in these uncommon clinical conditions are not just the product of the inflammation but rather may contribute to the development of a cytokine storm.

CONCLUSIONS

Here we review and compare four clinical conditions and the role of ferritin as an immunomodulator. We would like to propose including these four conditions under a common syndrome entity termed "Hyperferritinemic Syndrome".

Adult-onset Still disease (AOSD) is an uncommon inflammatory condition of unknown origin typically characterized by four main (cardinal) symptoms: spiking fever>> or =39 degrees C, arthralgia or arthritis, skin rash and hyperleucocytosis >> or =10,000 cells/mm3) with neutrophils>> or =80%. As many other manifestations are possible, diagnosis is potentially challenging. Determination of the total and glycosylated ferritin levels, although not pathognomonic, can help in diagnosis. The disease evolution of AOSD can be monocyclic, polycyclic or chronic. In chronic disease, joint involvement is often predominant and erosions are noted in one-third of patients. No prognostic factors have been identified to date. Therapeutic strategies are from observational data. Corticosteroids are usually the first-line treatment. With inadequate response to corticosteroids, methotrexate appears the best choice to control disease activity and allow for tapering of steroid use. For refractory disease, biological therapy with agents blocking interleukin-1 (anakinra) and then those blocking interleukin-6 (tocilizumab) seem the most promising.

OBJECTIVE

Interleukin-18 (IL-18) is a proinflammatory cytokine that is involved in immunologically mediated tissue damage, but its bioactivity is regulated in vivo by its soluble decoy receptor, IL-18 binding protein (IL-18BP). This study was undertaken to determine levels of IL-18 and IL-18 binding inhibition in the blood of patients with adult-onset Still's disease (ASD).

METHODS

Serum concentrations of IL-18 in ASD patients were compared by enzyme-linked immunosorbent assay (ELISA) with those in patients with other systemic rheumatic diseases and healthy controls. The biologically active mature protein of IL-18 was detected by Western blot analysis with anti-IL-18 antibody and its induction of interferon-gamma (IFNgamma) secretion from IL-18-responding human myelomonocytic KG-1 cells. The inhibitory activity on IL-18 binding to its receptor was determined by 125I-IL-18 binding inhibition assay using the Chinese hamster ovary cell line transfected with a murine IL-18 receptor (CHO-K1/mIL-18R).

RESULTS

Concentrations of serum IL-18 were extremely elevated in patients with active ASD compared with those in patients with rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, polymyositis/dermatomyositis, Sjogren's syndrome, or healthy individuals. Levels of IL-18 were found to correlate with serum ferritin values and disease severity in ASD. Western blot analysis revealed that serum samples from patients with active ASD contained an 18-kd polypeptide of IL-18, corresponding in size to the mature form. Accordingly, the samples were able to induce IFNgamma secretion from KG-1 cells, which was largely abolished by neutralizing anti-IL-18 antibody. However, the level of IL-18 bioactivity was more than 10-fold weaker than the concentration of IL-18 protein measured by ELISA. Serum samples from patients with active ASD showed an inhibitory effect on the binding of 125I-IL-18 to CHO-K1/mIL-18R cells, and this activity was associated with elevation of IL-18.

CONCLUSIONS

These data indicate that systemic overproduction of IL-18 may be closely related to the pathogenesis of ASD, despite the restriction on its inflammatory activity by IL-18 binding inhibitors such as IL-18BP. The disease activity appears to be determined on the basis of the relative levels of IL-18 and its specific inhibitors.

OBJECTIVE

To investigate concentrations of proinflammatory cytokines in the sera and their mRNA expression in biopsy specimens of evanescent rash and synovitis from patients with active untreated adult onset Still's disease (AOSD).

METHODS

We measured serum levels of interleukin 6 (IL-6), IL-8, and tumor necrosis factor (TNF-alpha) by immunochemiluminescence method and serum IL-18 levels by ELISA in 50 patients with active untreated AOSD, 20 patients with active rheumatoid arthritis (RA), and 20 healthy controls. Multivariate analysis was used to evaluate the correlation between serum cytokine levels and disease activity and clinical features of AOSD. We also evaluated the expression of cytokine transcripts by real-time quantitative polymerase chain reaction in biopsy specimens of evanescent rash and synovitis from 12 patients with active untreated AOSD.

RESULTS

Significantly higher levels of IL-6, IL-8, IL-18, and TNF-alpha in sera were found in patients with active untreated AOSD compared to healthy controls. Serum levels of IL-6 and IL-18 correlated well with clinical activity score of AOSD patients. Multiple logistic regression analysis showed that serum IL-6 level was a possible predictor for the occurrence of evanescent rash (p = 0.0593), serum IL-8 level was a significant predictor of persistent arthritis, and serum IL-18 level predicted occurrence of liver dysfunction. The levels of mRNA expression of IL-6, IL-18, and IL-8 were significantly higher in the biopsy tissue of Still's rash from AOSD patients compared with those in controls. Levels of mRNA expression of IL-18, IL-8, and TNF-alpha were significantly higher in the synovial membranes of AOSD patients compared with those in osteoarthritis controls. Significantly lower levels of TNF-alpha and IL-8 were found in the sera and in the synovial membranes of AOSD patients compared with those in RA patients. AOSD patients who had a chronic articular course had significantly higher levels of serum IL-8 compared with those who had a monocyclic systemic course.

CONCLUSIONS

Significantly higher levels of IL-6, IL-8, IL-18, and TNF-alpha were seen in both sera and pathological tissues of patients with active AOSD. The associations between levels of cytokine profile and distinct clinical manifestations and various patterns of disease course suggest the heterogeneity of pathogenesis in AOSD.

The ongoing pandemic coronavirus disease 19 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a matter of global concern. Environmental factors such as air pollution and smoking and comorbid conditions (hypertension, diabetes mellitus and underlying cardio-respiratory illness) likely increase the severity of COVID-19. Rheumatic manifestations such as arthralgias and arthritis may be prevalent in about a seventh of individuals. COVID-19 can result in acute interstitial pneumonia, myocarditis, leucopenia (with lymphopenia) and thrombocytopenia, also seen in rheumatic diseases like lupus and Sjogren's syndrome. Severe disease in a subset of patients may be driven by cytokine storm, possibly due to secondary hemophagocytic lymphohistiocytosis (HLH), akin to that in systemic onset juvenile idiopathic arthritis or adult-onset Still's disease. In the absence of high-quality evidence in this emerging disease, understanding of pathogenesis may help postulate potential therapies. Angiotensin converting enzyme 2 (ACE2) appears important for viral entry into pneumocytes; dysbalance in ACE2 as caused by ACE inhibitors or ibuprofen may predispose to severe disease. Preliminary evidence suggests potential benefit with chloroquine or hydroxychloroquine. Antiviral drugs like lopinavir/ritonavir, favipiravir and remdesivir are also being explored. Cytokine storm and secondary HLH might require heightened immunosuppressive regimens. Current international society recommendations suggest that patients with rheumatic diseases on immunosuppressive therapy should not stop glucocorticoids during COVID-19 infection, although minimum possible doses may be used. Disease-modifying drugs should be continued; cessation may be considered during infection episodes as per standard practices. Development of a vaccine may be the only effective long-term protection against this disease.Key Points• Patients with coronavirus disease 19 (COVID-19) may have features mimicking rheumatic diseases, such as arthralgias, acute interstitial pneumonia, myocarditis, leucopenia, lymphopenia, thrombocytopenia and cytokine storm with features akin to secondary hemophagocytic lymphohistiocytosis.• Although preliminary results may be encouraging, high-quality clinical trials are needed to better understand the role of drugs commonly used in rheumatology like hydroxychloroquine and tocilizumab in COVID-19.• Until further evidence emerges, it may be cautiously recommended to continue glucocorticoids and other disease-modifying antirheumatic drugs (DMARDs) in patients receiving these therapies, with discontinuation of DMARDs during infections as per standard practice.

OBJECTIVE

To estimate the incidence of adult Still's disease (ASD) and to specify, if possible, associated factors.

METHODS

A retrospective study of the populations of the Brittany and Loire regions in west France was made from 1 January 1982 to 31 December 1991. All internal medicine and rheumatology practitioners of these regions were consulted.

RESULTS

Sixty-two (62) cases were reported (93% response). The disease incidence calculated over five years was 0.16 per 100,000 inhabitants in the study population. There was no sex bias (sex ratio 1.06 in ASD v 1.05 in the overall population. The mean age of the study population was 36 years, with two peaks of distribution at 15-25 and 36-45 years. A history of allergy was present in 23% of patients (n = 14). In two patients, it was possible to correlate an environmental allergen to exacerbation of ASD.

CONCLUSIONS

The yearly incidence of ASD was estimated to be 0.16 per 100,000 inhabitants. However, it was not possible to incriminate any infectious, toxic, or genetic factors in exacerbation of the disease.

OBJECTIVE

To determine the usefulness of serum ferritin and glycosylated ferritin (GF) levels in diagnosing adult onset Still's disease (AOSD).

METHODS

We performed a retrospective multicenter study of 205 patients who had ferritin and GF assays in one hospital laboratory. Records of all patients were reviewed, and a standardized questionnaire used to extract all data available at the time of the assay. The clinicians' final diagnosis was also recorded. Patients were classified as having "certain AOSD" (based on Yamaguchi's criteria) or a control disease. The concordance of ferritin and GF levels with final diagnosis was evaluated.

RESULTS

In total 49 AOSD and 120 control patients were eligible. The mean ferritin value was significantly higher in the AOSD group (4,752 +/- 9,599 microg/l) than in the control group (1,571 +/- 3,807 microg/l), p = 0.029. GF was significantly lower in AOSD patients (15.9 +/- 11.9%) than in the control group (31.5 +/- 18.7%), p < 0.001. The combination of a GF level of < or = 20% with ferritin above the upper limit of normal yielded a sensitivity of 70.5% and specificity of 83.2%. The combination of a GF level < or = 20% with ferritin 5 times normal produced a sensitivity of 43.2% and specificity of 92.9%. This latter combination allowed an AOSD diagnosis to be ruled out for 6 of the 8 control patients who met Yamaguchi's positive criteria.

CONCLUSIONS

Ferritin and GF levels are powerful diagnostic markers of AOSD. They may be helpful in clinical practice for excluding differential diagnoses.

Infliximab, a chimeric anti-tumor necrosis factor-alpha monoclonal antibody, has been demonstrated to be efficient and safe in patients with active rheumatoid arthritis and in the management of severe bouts of Crohn's disease. However, the safety of infliximab has not been evaluated in patients infected with hepatitis B virus. We report the case of a 28-year-old woman, with a positive hepatitis B virus surface antigen, who developed fulminant hepatitis 2 weeks after receiving a second infliximab infusion for a refractory adult onset Still's disease.

OBJECTIVE

To examine the prevalence and characteristics of patients with reactive haemophagocytic syndrome (RHS) complicating adult-onset Still's disease (AOSD).

METHODS

Of 50 patients with AOSD fulfilling Yamaguchi and Fautrel criteria followed in our department, clinical and laboratory data, course and treatment of six patients with histologically proven RHS and without any obvious cause other than AOSD were retrospectively recorded.

RESULTS

RHS led to AOSD in two cases, whereas it appeared after a mean duration of 3.5 years from onset of AOSD in the other cases. The main symptoms were fever (n = 6), polyarthralgias or myalgias (n = 4), lymphadenopathy or splenomegaly (n = 3), pharyngitis (n = 3), rash (n = 3), pleuritis (n = 3), hepatomegaly (n = 1), normal or low leucocyte count (n = 4), anaemia (n = 6), lymphocytopenia (n = 6), thrombocytopenia (n = 4), hyperbasophilic lymphocytes (n = 2), abnormal liver function tests (n = 6) and increased serum triglyceride level (n = 6). Serum ferritin concentration was constantly increased (>10,000 microg/l in five cases, with <5-35% in glycosylated form). Two patients presented with coagulopathy. Treatment comprised corticosteroids (n = 4) and intravenous immunoglobulins (n = 3), whereas prednisone was unchanged in one case. One death due to pneumonia occurred 15 days after RHS. With a follow-up ranging from 2 to 7.5 years, the other patients were in remission with prednisone plus etanercept (n = 1), prednisone plus methotrexate (n = 1), low-dose prednisone (n = 2) or without treatment (n = 1).

CONCLUSIONS

RHS is not uncommon in AOSD. It should be evoked in a patient with AOSD in the absence of hyperleucocytosis, thrombocytopenia, lymphopenia and coagulopathy, or in the presence of high serum ferritin and triglyceride levels.

In 1973, IL-6 was identified as a soluble factor that is secreted by T cells and is important for antibody production by B cells. Since its discovery more than 40 years ago, the IL-6 pathway has emerged as a pivotal pathway involved in immune regulation in health and dysregulation in many diseases. Targeting of the IL-6 pathway has led to innovative therapeutic approaches for various rheumatic diseases, such as rheumatoid arthritis, juvenile idiopathic arthritis, adult-onset Still's disease, giant cell arteritis and Takayasu arteritis, as well as other conditions such as Castleman disease and cytokine release syndrome. Targeting this pathway has also identified avenues for potential expansion into several other indications, such as uveitis, neuromyelitis optica and, most recently, COVID-19 pneumonia. To mark the tenth anniversary of anti-IL-6 receptor therapy worldwide, we discuss the history of research into IL-6 biology and the development of therapies that target IL-6 signalling, including the successes and challenges and with an emphasis on rheumatic diseases.

We conducted a retrospective observational study to describe a cohort and identify the prognostic factors in adult-onset Still disease (AOSD). Patients enrolled in this retrospective chart review fulfilled either Yamaguchi or Fautrel criteria. Candidate variables were analyzed with logistic unadjusted and adjusted regression models. Fifty-seven patients were seen in the internal medicine (75%) and rheumatology (25%) departments over a mean period of 8.4 years. The median time to diagnosis was 4 months. The course of AOSD was monocyclic in 17 patients, polycyclic in 25, and chronic in 15. The assessment of glycosylated ferritin (GF) in 37 patients was correlated with early diagnosis. Nine F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans identified the lymph nodes and glands as the main sites of hypermetabolism. Complications were frequent (n = 19), including reactive hemophagocytic syndrome (n = 8). None of the 3 deaths could be attributed to AOSD. Corticosteroid dependence, as predicted by a low GF level, occurred in 23 patients (45%). A quarter of the patients received tumor necrosis factor-α blockers or anakinra with good tolerance. Fever >39.5 °C was predictive of monocyclic AOSD, while arthritis and thrombocytopenia were associated with chronic and complicated AOSD, respectively. The youngest patients had the highest risks of resistance to first-line treatments.AOSD remains difficult to diagnose. Mortality is low despite frequent complications. GF and FDG-PET scans were of value in the diagnostic approach. The condition in highly symptomatic patients evolved to systemic AOSD, whereas more progressive patterns with arthritis predicted chronic AOSD.

The severe form of COVID-19 share several clinical and laboratory features with four entities gathered under the term "hyperferritinemic syndrome" and including macrophage activation syndrome (MAS), adult-onset Still's disease (AOSD), catastrophic anti-phospholipid syndrome (CAPS) and septic shock. COVID-19 systemic inflammatory reaction and "hyperferritinemic syndromes" are all characterized by high serum ferritin and a life-threatening hyper-inflammation sustained by a cytokines storm which eventually leads to multi-organ failure. In this review, we analyze the possible epidemiological and molecular mechanisms responsible for hyper-inflammation in patients with severe COVID-19 and we underline the similarities between this condition and "hyperferritinemic syndromes" which would allow considering this entity as the fifth member of the spectrum of inflammatory conditions.

Interleukin-6 (IL-6) is a pleiotropic cytokine with various biological activities. Deregulated overproduction of IL-6 has been found to play pathological roles in chronic inflammatory diseases such as rheumatoid arthritis, Castleman's disease, juvenile idiopathic arthritis and Crohn's disease. Humanized anti-IL-6 receptor antibody has been developed as a therapeutic agent for these diseases, and therapeutic benefits have been revealed in clinical studies.

OBJECTIVE

To determine the efficacy of the interleukin (IL)-1-receptor antagonist (IL-1RA) anakinra in patients with adult-onset Still's disease (AOSD) refractory to standard treatments such as glucocorticosteroids (GC), immunosuppressive drugs, and tumor necrosis factor (TNF)-antagonists; to verify disease remission objectively by serial cytokine measurements; and to review the current literature on anakinra for this indication.

METHODS

Four patients with AOSD--2 with acute flares of the chronic form of the disease and 2 with intermittent disease--were treated with prednisolone and methotrexate. One was also treated with several other immunosuppressive drugs including etanercept and infliximab. One patient had life-threatening symptoms (toxic megacolon, pneumonitis, disseminated intravascular coagulation) despite high-dose prednisolone. Treatment with anakinra 100 mg/d subcutaneously was initiated. White blood cells (WBC), C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), liver enzymes, ferritin levels, and serum cytokines were analyzed. The current literature on the efficacy of anakinra for AOSD is reviewed.

RESULTS

Patients with chronic AOSD quickly responded to anakinra treatment (1 day to 3 days). GC could be tapered. ESR, CRP, WBC, ferritin, and liver enzymes returned to normal. Serum cytokine measurements revealed moderately elevated IL-1beta levels and highly elevated IL-18 levels in active disease, which normalized with anakinra. TNF-alpha and IL-6 were moderately elevated only in the 2 patients with chronic AOSD. In the literature, 17 similar cases have been reported to date.

CONCLUSIONS

Anakinra is effective in treatment-resistant and in life-threatening AOSD. IL-18 serum levels, in addition to CRP, ESR, liver enzymes, ferritin, and WBC, may be helpful in assessing disease activity and response to treatment.

OBJECTIVE

To analyze clinical manifestations, serum ferritin, and serum cytokine levels in patients with adult-onset Still's disease (AOSD) or bacterial sepsis and to evaluate their potential use for differential diagnosis.

METHODS

Twenty-two consecutive patients with the first flare of AOSD and 6 patients with an established diagnosis of AOSD under immunosuppressive therapy were compared with 14 patients with bacterial sepsis. Clinical manifestations were scored in a Pouchot AOSD activity score including elevated serum ferritin levels to obtain a modified Pouchot score. Serum cytokine profiles were analyzed from each patient.

RESULTS

The scores of clinical manifestations using a modified Pouchot activity score were significantly higher in patients with active untreated AOSD (mean 5.60 ± 1.93) compared with patients with chronic AOSD (mean 1.16 ± 0.98; p < 0.001) and patients with sepsis (mean 2.38 ± 1.19; p < 0.001). A modified Pouchot score ≥ 4 shows a sensitivity of 92% and a specificity of 93% for active AOSD. Serum cytokine levels of interleukin 1ß (IL-1ß), IL-6, IL-8, IL-10, IL-12, IL-18, interferon-γ, tumor necrosis factor-α, and calprotectin were elevated in acute AOSD and sepsis. Significant differences were detected only in patients with sepsis who had higher levels of IL-6 and IL-8. The overlap of the 2 groups limits the use of cytokines for differential diagnosis in individual patients.

CONCLUSIONS

A modified Pouchot AOSD activity score including elevated serum ferritin levels was more useful to confirm the diagnosis of AOSD compared to patients with sepsis. Elevated serum cytokines correlate with inflammation but are of limited use to differentiate between active AOSD and bacterial sepsis.

OBJECTIVE

Adult onset Still's disease (AOSD) is a systemic inflammatory disorder characterized by fever, arthritis, and rash. Although the pathogenesis is not known, immunologically mediated inflammation occurs in active AOSD. To evaluate the pathogenesis and disease activity of AOSD, we measured serial serum concentrations of several cytokines in patients with active and inactive disease.

METHODS

Seventeen patients diagnosed as having AOSD were enrolled. We analyzed clinical and laboratory findings retrospectively. Serial serum samples were obtained from 14 patients with active and inactive AOSD. Interleukin 18 (IL-18), soluble IL-2 receptor (sIL-2R), IL-6, interferon-g (IFN-g), and IL-8 were determined by ELISA.

RESULTS

Serum levels of IL-18, IFN-g, and IL-8 were significantly higher in patients with AOSD than in healthy controls (p < 0.01), but there were no significant differences between patients with active and inactive AOSD. Serum sIL-2R levels tended to be higher in the active state than in healthy controls, but there was no statistically significant difference between the 2 groups. Serum sIL-2R levels decreased significantly with antiinflammatory therapy (p < 0.05). Serum IL-18 and sIL-2R levels correlated significantly with serum ferritin levels in the active AOSD group (p < 0.05).

CONCLUSIONS

Overproduction of IL-18 may contribute to the pathogenic mechanism of AOSD, and serum sIL-2R levels may be used as a marker for monitoring disease activity in AOSD.