Regulatory T cells (T reg cells) are a population of CD4+ T cells that limit immune responses. FoxP3 is a master control transcription factor for development and function of these cells, but its regulation is poorly understood. We have identified a T cell receptor-responsive enhancer in the FoxP3 first intron that is dependent on a cyclic-AMP response element binding protein (CREB)/activating transcription factor (ATF) site overlapping a CpG island. Methylation of this island inversely correlates with CREB binding and FoxP3 expression. Interestingly, transforming growth factor-beta, which induces T reg cell formation, decreases methylation of the CpG island and increases FoxP3 expression. Similarly, inhibiting methylation with 5-azacytidine or knocking down the DNA methyltransferase Dnmt1 also induces FoxP3 expression. Conversely, methylation of the CpG island, which decreases CREB binding or expression of dominant-negative CREB, decreases FoxP3 gene expression. Thus, T cell receptor-induced FoxP3 expression in T reg cells is controlled both by sequence-specific binding of CREB/ATF and by DNA methylation of a CpG island.

We study the evolution of inversions that capture locally adapted alleles when two populations are exchanging migrants or hybridizing. By suppressing recombination between the loci, a new inversion can spread. Neither drift nor coadaptation between the alleles (epistasis) is needed, so this local adaptation mechanism may apply to a broader range of genetic and demographic situations than alternative hypotheses that have been widely discussed. The mechanism can explain many features observed in inversion systems. It will drive an inversion to high frequency if there is no countervailing force, which could explain fixed differences observed between populations and species. An inversion can be stabilized at an intermediate frequency if it also happens to capture one or more deleterious recessive mutations, which could explain polymorphisms that are common in some species. This polymorphism can cycle in frequency with the changing selective advantage of the locally favored alleles. The mechanism can establish underdominant inversions that decrease heterokaryotype fitness by several percent if the cause of fitness loss is structural, while if the cause is genic there is no limit to the strength of underdominance that can result. The mechanism is expected to cause loci responsible for adaptive species-specific differences to map to inversions, as seen in recent QTL studies. We discuss data that support the hypothesis, review other mechanisms for inversion evolution, and suggest possible tests.

In many organisms, introducing double-stranded RNA (dsRNA) causes the degradation of messenger RNA that is homologous to the trigger dsRNA--a process known as RNA interference. The dsRNA is cleaved into short interfering RNAs (siRNAs), which hybridize to homologous mRNAs and induce their degradation. dsRNAs vary in their ability to trigger RNA interference: many mRNA-targeting dsRNAs show weak phenotypes, and nearly all mRNAs of the Caenorhabditis elegans nervous system are refractory to RNA interference. C. elegans eri-1 was identified in a genetic screen for mutants with enhanced sensitivity to dsRNAs. Here we show that eri-1 encodes an evolutionarily conserved protein with domains homologous to nucleic-acid-binding and exonuclease proteins. After exposure to dsRNA or siRNAs, animals with eri-1 mutations accumulate more siRNAs than do wild-type animals. C. elegans ERI-1 and its human orthologue degrade siRNAs in vitro. In the nematode worm, ERI-1 is predominantly cytoplasmic and is expressed most highly in the gonad and a subset of neurons, suggesting that ERI-1 siRNase activity suppresses RNA interference more intensely in these tissues. Thus, ERI-1 is a negative regulator that may normally function to limit the duration, cell-type specificity or endogenous functions of RNA interference.

We have purified the 36 and 63 kd cellular proteins known to associate with polyomavirus middle and small tumor (T) antigens and SV40 small t antigen. Microsequencing of the 36 kd protein indicated that it was probably identical to the catalytic subunit of protein phosphatase 2A (PP2A). Identity was confirmed by comigration on two-dimensional (2D) gels and by 2D analysis of complete chymotryptic digests. In addition, PP2A-like phosphatase activity was detected in immunoprecipitates of wild-type middle T. Immunoblotting experiments, comigration on 2D gels, and 2D analysis of limit chymotryptic digests demonstrated that the 63 kd protein, present in the middle T complex in approximately equimolar ratio to the 36 kd protein, is a known regulatory subunit of the PP2A holoenzyme. Finally, the 36 kd PP2A catalytic subunit can be immunoprecipitated by anti-pp60c-src antisera only from cells expressing wild-type middle T. These results suggest that complex formation between PP2A and T antigens may be important for T antigen-mediated transformation.

Estimates of hemodynamic response functions (HRF) are often integral parts of event-related fMRI analyses. Although HRFs vary across individuals and brain regions, few studies have investigated how variations affect the results of statistical analyses using the general linear model (GLM). In this study, we empirically estimated HRFs from primary motor and visual cortices and frontal and supplementary eye fields (SEF) in 20 subjects. We observed more variability across subjects than regions and correlated variation of time-to-peak values across several pairs of regions. Simulations examined the effects of observed variability on statistical results and ways different experimental designs and statistical models can limit these effects. Widely spaced and rapid event-related experimental designs with two sampling rates were tested. Statistical models compared an empirically derived HRF to a canonical HRF and included the first derivative of the HRF in the GLM. Small differences between the estimated and true HRFs did not cause false negatives, but larger differences within an observed range of variation, such as a 2.5-s time-to-onset misestimate, led to false negatives. Although small errors minimally affected detection of activity, time-to-onset misestimates as small as 1 s influenced model parameter estimation and therefore random effects analyses across subjects. Experiment and analysis design methods such as decreasing the sampling rate or including the HRF's temporal derivative in the GLM improved results, but did not eliminate errors caused by HRF misestimates. These results highlight the benefits of determining the best possible HRF estimate and potential negative consequences of assuming HRF consistency across subjects or brain regions.

The following diagnostic criteria are proposed to classify four clinical subtypes of HTLV-1 associated adult T-cell leukaemia-lymphoma (ATL): (1) Smouldering type, 5% or more abnormal lymphocytes of T-cell nature in PB, normal lymphocyte level (less than 4 x 10(9)/l), no hypercalcaemia (corrected calcium level less than 2.74 mmol/l), lactate dehydrogenase (LDH) value of up to 1.5 x the normal upper limit, no lymphadenopathy, no involvement of liver, spleen, central nervous system (CNS), bone and gastrointestinal tract, and neither ascites nor pleural effusion. Skin and pulmonary lesion(s) may be present. In case of less than 5% abnormal T-lymphocytes in PB, at least one of histologically-proven skin and pulmonary lesions should be present. (2) Chronic type, absolute lymphocytosis (4 x 10(9)/l or more) with T-lymphocytosis more than 3.5 x 10(9)/l, LDH value up to twice the normal upper limit, no hypercalcaemia, no involvement of CNS, bone and gastrointestinal tract, and neither ascites nor pleural effusion. Lymphadenopathy and involvement of liver, spleen, skin, and lung may be present, and 5% or more abnormal T-lymphocytes are seen in PB in most cases . (3) Lymphoma type, no lymphocytosis, 1% or less abnormal T-lymphocytes, and histologically-proven lymphadenopathy with or without extranodal lesions. (4) Acute type, remaining ATL patients who have usually leukaemic manifestation and tumour lesions, but are not classified as any of the three other types. A total of 818 ATL patients with a mean age of 57 years, newly diagnosed from 1983 to 1987, were analysed by this criteria. There were 448 males and 370 females, and 253 were still alive with a median follow-up time of 13.3 months from diagnosis, while 565 were dead with a median survival time (MST) of 5.4 months. MST was 6.2 months for acute type, 10.2 months for lymphoma type, 24.3 months for chronic type, and not yet reached for smouldering type. Projected 2- and 4-year survival rates were 16.7% and 5.0% for acute type, 21.3% and 5.7% for lymphoma type, 52.4% and 26.9% for chronic type, 77.7% and 62.8% for smouldering type, respectively. Distinct clinical features and laboratory findings of each clinical subtype are described.

The role of T cells in mediating heterosubtypic protection against natural influenza illness in humans is uncertain. The 2009 H1N1 pandemic (pH1N1) provided a unique natural experiment to determine whether crossreactive cellular immunity limits symptomatic illness in antibody-naive individuals. We followed 342 healthy adults through the UK pandemic waves and correlated the responses of pre-existing T cells to the pH1N1 virus and conserved core protein epitopes with clinical outcomes after incident pH1N1 infection. Higher frequencies of pre-existing T cells to conserved CD8 epitopes were found in individuals who developed less severe illness, with total symptom score having the strongest inverse correlation with the frequency of interferon-γ (IFN-γ)(+) interleukin-2 (IL-2)(-) CD8(+) T cells (r = -0.6, P = 0.004). Within this functional CD8(+)IFN-γ(+)IL-2(-) population, cells with the CD45RA(+) chemokine (C-C) receptor 7 (CCR7)(-) phenotype inversely correlated with symptom score and had lung-homing and cytotoxic potential. In the absence of crossreactive neutralizing antibodies, CD8(+) T cells specific to conserved viral epitopes correlated with crossprotection against symptomatic influenza. This protective immune correlate could guide universal influenza vaccine development.

There is need for a validated short, simple instrument to quantify chronic obstructive pulmonary disease (COPD) impact in routine practice to aid health status assessment and communication between patient and physician. Current health-related quality of life questionnaires provide valid assessment of COPD, but are complex, which limits routine use. The aim of the present study was to develop a short validated patient-completed questionnaire, the COPD Assessment Test (CAT), assessing the impact of COPD on health status. 21 candidate items identified through qualitative research with COPD patients were used in three prospective international studies (Europe and the USA, n = 1,503). Psychometric and Rasch analyses identified eight items fitting a unidimensional model to form the CAT. Items were tested for differential functioning between countries. Internal consistency was excellent: Cronbach's alpha = 0.88. Test re-test in stable patients (n = 53) was very good (intra-class correlation coefficient 0.8). In the sample from the USA, the correlation with the COPD-specific version of the St George's Respiratory Questionnaire was r = 0.80. The difference between stable (n = 229) and exacerbation patients (n = 67) was five units of the 40-point scale (12%; p<0.0001). The CAT is a short, simple questionnaire for assessing and monitoring COPD. It has good measurement properties, is sensitive to differences in state and should provide a valid, reliable and standardised measure of COPD health status with worldwide relevance.

The hypothesis that Attention-Deficit/Hyperactivity Disorder (ADHD) reflects a primary inhibitory executive function deficit has spurred a substantial literature. However, empirical findings and methodological issues challenge the etiologic primacy of inhibitory and executive deficits in ADHD. Based on accumulating evidence of increased intra-individual variability in ADHD, we reconsider executive dysfunction in light of distinctions between 'hot' and 'cool' executive function measures. We propose an integrative model that incorporates new neuroanatomical findings and emphasizes the interactions between parallel processing pathways as potential loci for dysfunction. Such a reconceptualization provides a means to transcend the limits of current models of executive dysfunction in ADHD and suggests a plan for future research on cognition grounded in neurophysiological and developmental considerations.

OBJECTIVE

To investigate the efficacy of preoperative short-term radiotherapy in patients with mobile rectal cancer undergoing total mesorectal excision (TME) surgery.

BACKGROUND

Local recurrence is a major problem in rectal cancer treatment. Preoperative short-term radiotherapy has shown to improve local control and survival in combination with conventional surgery. The TME trial investigated the value of this regimen in combination with total mesorectal excision. Long-term results are reported after a median follow-up of 6 years.

METHODS

One thousand eight hundred and sixty-one patients with resectable rectal cancer were randomized between TME preceded by 5 x 5 Gy or TME alone. No chemotherapy was allowed. There was no age limit. Surgery, radiotherapy, and pathologic examination were standardized. Primary endpoint was local control.

RESULTS

Median follow-up of surviving patients was 6.1 year. Five-year local recurrence risk of patients undergoing a macroscopically complete local resection was 5.6% in case of preoperative radiotherapy compared with 10.9% in patients undergoing TME alone (P < 0.001). Overall survival at 5 years was 64.2% and 63.5%, respectively (P = 0.902). Subgroup analyses showed significant effect of radiotherapy in reducing local recurrence risk for patients with nodal involvement, for patients with lesions between 5 and 10 cm from the anal verge, and for patients with uninvolved circumferential resection margins.

CONCLUSIONS

With increasing follow-up, there is a persisting overall effect of preoperative short-term radiotherapy on local control in patients with clinically resectable rectal cancer. However, there is no effect on overall survival. Since survival is mainly determined by distant metastases, efforts should be directed towards preventing systemic disease.

Uterine leiomyomas (fibroids or myomas), benign tumours of the human uterus, are the single most common indication for hysterectomy. They are clinically apparent in up to 25% of women and cause significant morbidity, including prolonged or heavy menstrual bleeding, pelvic pressure or pain, and, in rare cases, reproductive dysfunction. Thus, both the economic cost and the effect on quality of life are substantial. Surgery has been the mainstay of fibroid treatment, and various minimally invasive procedures have been developed in addition to hysterectomy and abdominal myomectomy. Formation of new leiomyomas after these conservative therapies remains a substantial problem. Although medications that manipulate concentrations of steroid hormones are effective, side-effects limit long-term use. A better approach may be manipulation of the steroid-hormone environment with specific hormone antagonists. There has been little evidence-based evaluation of therapy. New research into the basic biology of these neoplasms may add new treatment options for the future as the role of growth factors and genetic mutations in these tumours are better understood.

Chronic inflammation is frequently associated with malignant growth and is thought to promote and enhance tumor progression, although the mechanisms which regulate this relationship remain elusive. We reported previously that interleukin (IL)-1beta promoted tumor progression by enhancing the accumulation of myeloid-derived suppressor cells (MDSC), and hypothesized that inflammation leads to cancer through the production of MDSC which inhibit tumor immunity. If inflammation-induced MDSC promote tumor progression by blocking antitumor immunity, then a reduction in inflammation should reduce MDSC levels and delay tumor progression, whereas an increase in inflammation should increase MDSC levels and hasten tumor progression. We have tested this hypothesis using the 4T1 mammary carcinoma and IL-1 receptor (IL-1R)-deficient mice which have a reduced potential for inflammation, and IL-1R antagonist-deficient mice, which have an increased potential for inflammation. Consistent with our hypothesis, IL-1R-deficient mice have a delayed accumulation of MDSC and reduced primary and metastatic tumor progression. Accumulation of MDSC and tumor progression are partially restored by IL-6, indicating that IL-6 is a downstream mediator of the IL-1beta-induced expansion of MDSC. In contrast, excessive inflammation in IL-1R antagonist-deficient mice promotes the accumulation of MDSC and produces MDSC with enhanced suppressive activity. These results show that immune suppression by MDSC and tumor growth are regulated by the inflammatory milieu and support the hypothesis that the induction of suppressor cells which down-regulate tumor immunity is one of the mechanisms linking inflammation and cancer.

NHE3 is one of five plasma membrane Na+/H+ exchangers and is encoded by the mouse gene Slc9a3. It is expressed on apical membranes of renal proximal tubule and intestinal epithelial cells and is thought to play a major role in NaCl and HCO3- absorption. As the distribution of NHE3 overlaps with that of the NHE2 isoform in kidney and intestine, the function and relative importance of NHE3 in vivo is unclear. To analyse its physiological functions, we generated mice lacking NHE3 function. Homozygous mutant (Slc9a3-/-) mice survive, but they have slight diarrhoea and blood analysis revealed that they are mildly acidotic. HCO3- and fluid absorption are sharply reduced in proximal convoluted tubules, blood pressure is reduced and there is a severe absorptive defect in the intestine. Thus, compensatory mechanisms must limit gross perturbations of electrolyte and acid-base balance. Plasma aldosterone is increased in NHE3-deficient mice, and expression of both renin and the AE1 (Slc4a1) Cl-/HCO3- exchanger mRNAs are induced in kidney. In the colon, epithelial Na+ channel activity is increased and colonic H+,K+-ATPase mRNA is massively induced. These data show that NHE3 is the major absorptive Na+/H+ exchanger in kidney and intestine, and that lack of the exchanger impairs acid-base balance and Na+-fluid volume homeostasis.

Few techniques are currently available for quantifying specific prokaryotic taxa in environmental samples. Quantification of specific genotypes has relied mainly on oligonucleotide hybridization to extracted rRNA or intact rRNA in whole cells. However, low abundance and cellular rRNA content limit the application of these techniques in aquatic environments. In this study, we applied a newly developed quantitative PCR assay (5'-nuclease assay, also known as TaqMan) to quantify specific small-subunit (SSU) rRNA genes (rDNAs) from uncultivated planktonic prokaryotes in Monterey Bay. Primer and probe combinations for quantification of SSU rDNAs at the domain and group levels were developed and tested for specificity and quantitative reliability. We examined the spatial and temporal variations of SSU rDNAs from Synechococcus plus Prochlorococcus and marine Archaea and compared the results of the quantitative PCR assays to those obtained by alternative methods. The 5'-nuclease assays reliably quantified rDNAs over at least 4 orders of magnitude and accurately measured the proportions of genes in artificial mixtures. The spatial and temporal distributions of planktonic microbial groups measured by the 5'-nuclease assays were similar to the distributions estimated by quantitative oligonucleotide probe hybridization, whole-cell hybridization assays, and flow cytometry.

The subjective sense of future time plays an essential role in human motivation. Gradually, time left becomes a better predictor than chronological age for a range of cognitive, emotional, and motivational variables. Socioemotional selectivity theory maintains that constraints on time horizons shift motivational priorities in such a way that the regulation of emotional states becomes more important than other types of goals. This motivational shift occurs with age but also appears in other contexts (for example, geographical relocations, illnesses, and war) that limit subjective future time.

Multiplexed detection of oligonucleotide targets has been performed with gold nanoparticle probes labeled with oligonucleotides and Raman-active dyes. The gold nanoparticles facilitate the formation of a silver coating that acts as a surface-enhanced Raman scattering promoter for the dye-labeled particles that have been captured by target molecules and an underlying chip in microarray format. The strategy provides the high-sensitivity and high-selectivity attributes of gray-scale scanometric detection but adds multiplexing and ratioing capabilities because a very large number of probes can be designed based on the concept of using a Raman tag as a narrow-band spectroscopic fingerprint. Six dissimilar DNA targets with six Raman-labeled nanoparticle probes were distinguished, as well as two RNA targets with single nucleotide polymorphisms. The current unoptimized detection limit of this method is 20 femtomolar.

The green fluorescent protein (GFP) is a widely used reporter in gene expression and protein localization studies. GFP is a stable protein; this property allows its accumulation and easy detection in cells. However, this stability also limits its application in studies that require rapid reporter turnover. We created a destabilized GFP for use in such studies by fusing amino acids 422-461 of the degradation domain of mouse ornithine decarboxylase (MODC) to the C-terminal end of an enhanced variant of GFP (EGFP). The fusion protein, unlike EGFP, was unstable in the presence of cycloheximide and had a fluorescence half-life of 2 h. Western blot analysis indicated that the fluorescence decay of EGFP-MODC-(422-461) was correlated with degradation of the fusion protein. We mutated key amino acids in the PEST sequence of EGFP-MODC-(422-461) and identified several mutants with variable half-lives. The suitability of destabilized EGFP as a transcription reporter was tested by linking it to NFkappaB binding sequences and monitoring tumor necrosis factor alpha-mediated NFkappaB activation. We obtained time course induction and dose response kinetics similar to secreted alkaline phosphatase obtained in transfected cells. This result did not occur when unmodified EGFP was used as the reporter. Because of its autofluorescence, destabilized EGFP can be used to directly correlate gene induction with biochemical change, such as NFkappaB translocation to the nucleus.

BACKGROUND

Limited data are available evaluating how the timing and intensity of statin therapy following an acute coronary syndrome (ACS) event affect clinical outcome.

OBJECTIVE

To compare early initiation of an intensive statin regimen with delayed initiation of a less intensive regimen in patients with ACS.

METHODS

International, randomized, double-blind trial of patients with ACS receiving 40 mg/d of simvastatin for 1 month followed by 80 mg/d thereafter (n = 2265) compared with ACS patients receiving placebo for 4 months followed by 20 mg/d of simvastatin (n = 2232), who were enrolled in phase Z of the A to Z trial between December 29, 1999, and January 6, 2003.

METHODS

The primary end point was a composite of cardiovascular death, nonfatal myocardial infarction, readmission for ACS, and stroke. Follow-up was for at least 6 months and up to 24 months.

RESULTS

Among the patients in the placebo plus simvastatin group, the median low-density lipoprotein (LDL) cholesterol level achieved while taking placebo was 122 mg/dL (3.16 mmol/L) at 1 month and was 77 mg/dL (1.99 mmol/L) at 8 months while taking 20 mg/d of simvastatin. Among the patients in the simvastatin only group, the median LDL cholesterol level achieved at 1 month while taking 40 mg/d of simvastatin was 68 mg/dL (1.76 mmol/L) and was 63 mg/dL (1.63 mmol/L) at 8 months while taking 80 mg/d of simvastatin. A total of 343 patients (16.7%) in the placebo plus simvastatin group experienced the primary end point compared with 309 (14.4%) in the simvastatin only group (40 mg/80 mg) (hazard ratio [HR], 0.89; 95% confidence interval [CI] 0.76-1.04; P =.14). Cardiovascular death occurred in 109 (5.4%) and 83 (4.1%) patients in the 2 groups (HR, 0.75; 95% CI, 0.57-1.00; P =.05) but no differences were observed in other individual components of the primary end point. No difference was evident during the first 4 months between the groups for the primary end point (HR, 1.01; 95% CI, 0.83-1.25; P =.89), but from 4 months through the end of the study the primary end point was significantly reduced in the simvastatin only group (HR, 0.75; 95% CI, 0.60-0.95; P =.02). Myopathy (creatine kinase >10 times the upper limit of normal associated with muscle symptoms) occurred in 9 patients (0.4%) receiving simvastatin 80 mg/d, in no patients receiving lower doses of simvastatin, and in 1 patient receiving placebo (P =.02).

CONCLUSIONS

The trial did not achieve the prespecified end point. However, among patients with ACS, the early initiation of an aggressive simvastatin regimen resulted in a favorable trend toward reduction of major cardiovascular events.

The variability of the discharge of visual cortical neurons in cats and macaque monkeys limits the reliability with which such neurons can relay signals about weak visual stimuli. In general, the variance of a neuron's firing rate is directly proportional to its mean firing rate. The probability that a neuron will fire a criterion number of impulses on a stimulus trial grows monotonically with the contrast of a sinusoidal grating stimulus. Neural probability functions prepared either by computing the probability of criterion response or by integrating receiver operating characteristics to yield the probability of correct choice in a two-alternative forced-choice situation resemble psychometric functions obtained in psychophysical and behavioral experiments on humans and animals, but are shallower in slope. The slopes of neuronal probability functions are slightly higher when they are estimated over short time periods, but even so do not equal the slopes measured psychophysically in human and monkey observers. This discrepancy in slope could be explained if the whole observer responded only when about four neurons were active together.

Secreted proteins of the Hedgehog (Hh) family have diverse organizing roles in animal development. Recently, a serpentine protein Smoothened (Smo) has been proposed as a Hh receptor. Here, we present evidence that implicates another multiple-pass transmembrane protein, Patched (Ptc), in Hh reception and suggests a novel signal transduction mechanism in which Hh binds to Ptc, or a Ptc-Smo complex, and thereby induces Smo activity. Our results also show that Ptc limits the range of Hh action; we provide evidence that high levels of Ptc induced by Hh serve to sequester any free Hh and therefore create a barrier to its further movement.

The reproducibility and precision of biological patterning is limited by the accuracy with which concentration profiles of morphogen molecules can be established and read out by their targets. We consider four measures of precision for the Bicoid morphogen in the Drosophila embryo: the concentration differences that distinguish neighboring cells, the limits set by the random arrival of Bicoid molecules at their targets (which depends on absolute concentration), the noise in readout of Bicoid by the activation of Hunchback, and the reproducibility of Bicoid concentration at corresponding positions in multiple embryos. We show, through a combination of different experiments, that all of these quantities are approximately 10%. This agreement among different measures of accuracy indicates that the embryo is not faced with noisy input signals and readout mechanisms; rather, the system exerts precise control over absolute concentrations and responds reliably to small concentration differences, approaching the limits set by basic physical principles.

Virus-specific CD8+ effector T cells (eCTL) are enriched in the lungs of mice with primary influenza pneumonia, though later detection of memory T cells (mCTL) in the mediastinal lymph nodes (MLN) or spleen by peptide-based staining protocols is at the limits of flow cytometric analysis. Respiratory challenge with an H3N2 virus months after H1N1 priming induces a massive recall response, which reduces virus titers 2-3 days earlier than in nave controls. Influenza-specific mCTL produce interferon-gamma within 6 hr, but still take 4-5 days to localize to the infected respiratory tract. The delay reflects that the recall response develops first in the MLN, which contains relatively few mCTL. The response to a subdominant epitope is less obvious after secondary challenge.

OBJECTIVE

To examine the efficacy and safety of the humanized anti-interleukin-6 receptor antibody tocilizumab combined with conventional disease-modifying antirheumatic drugs (DMARDs) in patients with active rheumatoid arthritis (RA).

METHODS

A total of 1,220 patients were randomized (2:1 ratio) in the phase III, double-blind, placebo-controlled, multicenter TOWARD (Tocilizumab in Combination With Traditional DMARD Therapy) study. Patients remained on stable doses of DMARDs and received tocilizumab 8 mg/kg or placebo (control group) every 4 weeks for 24 weeks.

RESULTS

At week 24, the proportion of patients achieving a response according to the American College of Rheumatology criteria for 20% improvement (ACR20) was significantly greater in the tocilizumab plus DMARD group than in the control group (61% versus 25%; P<0.0001). Secondary end points including 50% or 70% improvement (ACR50/70), the Disease Activity Score in 28 joints (DAS28), DAS28 remission responses (DAS28<2.6), European League Against Rheumatism responses, and systemic markers such as the C-reactive protein and hemoglobin levels showed superiority of tocilizumab plus DMARDs over DMARDs alone. Seventy-three percent of patients in the tocilizumab group had>>or=1 adverse event (AE), compared with 61% of patients in the control group. AEs leading to withdrawal from the study were infrequent (4% of patients in the tocilizumab group and 2% of those in the control group). Serious AEs occurred in 6.7% and 4.3% of patients in the tocilizumab and control groups, respectively, and serious infections occurred in 2.7% and 1.9%, respectively. Elevations in the alanine aminotransferase level, from normal at baseline to >3-fold the upper limit of normal, occurred in 4% of patients in the tocilizumab group and 1% of those in the control group, and elevated total cholesterol levels were observed in 23% and 6% of patients, respectively. Sixteen patients started lipid-lowering therapy during the study. Grade 3 neutropenia occurred in 3.7% of patients receiving tocilizumab and none of the patients in the control group, and no grade 4 neutropenia was reported.

CONCLUSIONS

Tocilizumab combined with any of the DMARDs evaluated was safe and effective in reducing articular and systemic symptoms in patients with an inadequate response to these agents.

The choice between double-strand break (DSB) repair by either homology-directed repair (HDR) or nonhomologous end joining (NHEJ) is tightly regulated. Defects in this regulation can induce genome instability and cancer. 53BP1 is critical for the control of DSB repair, promoting NHEJ, and inhibiting the 5' end resection needed for HDR. Using dysfunctional telomeres and genome-wide DSBs, we identify Rif1 as the main factor used by 53BP1 to impair 5' end resection. Rif1 inhibits resection involving CtIP, BLM, and Exo1; limits accumulation of BRCA1/BARD1 complexes at sites of DNA damage; and defines one of the mechanisms by which 53BP1 causes chromosomal abnormalities in Brca1-deficient cells. These data establish Rif1 as an important contributor to the control of DSB repair by 53BP1.