Patients with vasculitis induced by the hepatitis C virus (HCV) have reduced levels of regulatory T cells (Tregs). Resolution of HCV infection correlates with cure of vasculitis and the recovery of Treg levels. We reasoned that interleukin-2, a cytokine that promotes Treg survival and function, could be beneficial for patients with vasculitis that is resistant to HCV therapy. We investigated the safety and immunologic effects of the administration of low-dose interleukin-2 in a prospective open-label, phase 1–phase 2a study. Ten patients with HCV-induced vasculitis that was refractory to conventional antiviral therapy, rituximab therapy, or both and who were not receiving glucocorticoid or immunosuppressant therapy received one course of interleukin-2 (1.5 million IU per day) for 5 days, followed by three 5-day courses of 3 million IU per day at weeks 3, 6, and 9. Both the safety of the treatment and its effectiveness were evaluated, the latter by monitoring the Treg response and the clinical signs of HCV vasculitis. We observed one grade 2 dental abscess that required hospitalization for treatment with antibiotics. Other adverse events were grade 1. The treatment did not induce effector T-cell activation, vasculitis flare, or increased HCV viremia. We observed an improvement of vasculitis in 8 of 10 patients. Administration of low-dose interleukin-2 was followed by an increase in the percentage of CD4+, CD25^high, forkhead box P3 (FOXP3+) Tregs [E_max (maximum value)÷baseline value×100=420%] with potent suppressive activity in all subjects and by a concomitantly decreased proportion of marginal-zone B cells. Transcriptome studies of peripheral-blood mononuclear cells revealed that interleukin-2 induced a global attenuation of the signatures for inflammation and oxidative stress mediators. The trial showed that low-dose interleukin-2 led to Treg recovery and was associated with clinical improvement in 8 of 10 patients with HCV-induced vasculitis, an autoimmune condition. (Funded by the French Agency for Research on AIDS and Viral Hepatitis [ANRS] and others; ClinicalTrials.gov number, NCT00574652.)

Complement receptor 2–negative (CR2/CD21−) B cells have been found enriched in patients with autoimmune diseases and in common variable immunodeficiency (CVID) patients who are prone to autoimmunity. However, the physiology of CD21−/lo B cells remains poorly characterized. We found that some rheumatoid arthritis (RA) patients also display an increased frequency of CD21−/lo B cells in their blood. A majority of CD21−/lo B cells from RA and CVID patients expressed germline autoreactive antibodies, which recognized nuclear and cytoplasmic structures. In addition, these B cells were unable to induce calcium flux, become activated, or proliferate in response to B-cell receptor and/or CD40 triggering, suggesting that these autoreactive B cells may be anergic. Moreover, gene array analyses of CD21−/lo B cells revealed molecules specifically expressed in these B cells and that are likely to induce their unresponsive stage. Thus, CD21−/lo B cells contain mostly autoreactive unresponsive clones, which express a specific set of molecules that may represent new biomarkers to identify anergic B cells in humans.

Objective: To report the long‐term mortality in patients with Behçet's disease (BD).Methods: A cohort of 817 patients fulfilling the international criteria for BD from a single center in France were analyzed for causes of death, the standardized mortality ratio (SMR), and the factors associated with mortality.Results: Among the 817 patients with BD, 41 (5%) died after a median followup of 7.7 years, of whom 95.1% were male. The mean ± SD age at death was 34.8 ± 11.9 years. Main causes of death included major vessel disease (mainly, arterial aneurysm and Budd‐Chiari syndrome) (43.9%), cancer and malignant hemopathy (14.6%), central nervous system involvement (12.2%), and sepsis (12.2%). The mortality rate at 1 year and 5 years was 1.2% and 3.3%, respectively. There was an increased mortality among patients ages 15–24 years (SMR 2.99, 95% confidence interval [95% CI] 1.54–5.39) and those ages 25–34 years (SMR 2.90, 95% CI 1.80–4.49) as compared with age‐and sex‐matched healthy controls. The mortality decreased in patients older than age 35 years (SMR 1.23, 95% CI 0.75–1.92). In multivariate analyses, male sex (hazard ratio [HR] 4.94, 95% CI 1.53–16.43), arterial involvement (HR 2.51, 95% CI 1.07–5.90), and a high number of BD flares (HR 2.37, 95% CI 1.09–5.14) were independently associated with the risk of mortality.Conclusion: The overall mortality in our BD cohort was 5% after a median followup of 7.7 years. Male sex, arterial involvement, and the number of flares were associated with mortality in BD.

Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene polymorphisms are associated with many autoimmune diseases. The major risk allele encodes an R620W amino acid change that alters B cell receptor (BCR) signaling involved in the regulation of central B cell tolerance. To assess whether this PTPN22 risk allele affects the removal of developing autoreactive B cells, we tested by ELISA the reactivity of recombinant antibodies isolated from single B cells from asymptomatic healthy individuals carrying one or two PTPN22 risk allele(s) encoding the PTPN22 R620W variant. We found that new emigrant/transitional and mature naive B cells from carriers of this PTPN22 risk allele contained high frequencies of autoreactive clones compared with those from non-carriers, revealing defective central and peripheral B cell tolerance checkpoints. Hence, a single PTPN22 risk allele has a dominant effect on altering autoreactive B cell counterselection before any onset of autoimmunity. In addition, gene array experiments analyzing mature naive B cells displaying PTPN22 risk allele(s) revealed that the association strength of PTPN22 for autoimmunity may be due not only to the impaired removal of autoreactive B cells but also to the upregulation of genes such as CD40, TRAF1, and IRF5, which encode proteins that promote B cell activation and have been identified as susceptibility genes associated with autoimmune diseases. These data demonstrate that early B cell tolerance defects in autoimmunity can result from specific polymorphisms and precede the onset of disease.