David Saadoun

Regulatory T-Cell Responses to Low-Dose Interleukin-2 in HCV-Induced Vasculitis

BACKGROUND 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. METHODS 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. RESULTS No adverse events reached a level higher than grade 1. The treatment did not induce effector T-cell activation, vasculitis flare, or increased HCV viremia. We observed a reduction in cryoglobulinemia in 9 of 10 patients and improvement of vasculitis in 8 of 10. 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. CONCLUSIONS The trial showed that low-dose interleukin-2 was not associated with adverse effects and led to Treg recovery and concomitant clinical improvement in 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.).

The PTPN22 allele encoding an R620W variant interferes with the removal of developing autoreactive B cells in humans

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.

Rituximab plus Peg-interferon-α/ribavirin compared with Peg-interferon-α/ribavirin in hepatitis C-related mixed cryoglobulinemia.

Treatment of hepatitis C (HCV)-mixed cryoglobulinemia (MC) may target either the viral trigger (HCV) or the downstream B-cell clonal expansion. Prospective cohort study of 38 HCV-MC patients who received a combination of rituximab (375 mg/m(2)) once a week for 1 month followed by Peg-interferon-alpha (Peg-IFN-alpha; 2a, 180 microg or 2b, 1.5 microg/kg) weekly plus ribavirin (600-1200 mg) daily for 48 weeks were compared with 55 HCV-MC patients treated by Peg-IFN-alpha/ribavirin with the same modalities. In the whole population of HCV-MC patients (n = 93), a complete clinical response was achieved in 73.1% (68 of 93), cryoglobulin clearance in 52.7% (49 of 93), and a sustained virologic response in 59.1% (55 of 93). Compared with Peg-IFN-alpha/ribavirin, rituximab plus Peg-IFN-alpha/ribavirin-treated patients had a shorter time to clinical remission (5.4 +/- 4 vs 8.4 +/- 4.7 months, P = .004), better renal response rates (80.9% vs 40% of complete response, P = .040), and higher rates of cryoglobulin clearance (68.4% vs 43.6%, P = .001) and clonal VH1-69(+) B-cell suppression (P < .01). Treatment was well tolerated with 11% of discontinuation resulting from antiviral therapy and no worsening of HCV RNA under rituximab. Our findings indicate that rituximab combined with Peg-IFN-alpha/ribavirin is well tolerated and more effective than Peg-IFN-alpha/ribavirin in HCV-MC.

New insights into the pathogenesis of Behçet's disease.

Behçets disease (BD) is a recurrent systemic inflammatory disorder of unknown origin characterized by oral and genital mucous ulcer, uveitis, and skin lesions. Involvement of large vessels, central nervous system (CNS), gastrointestinal tract and thrombotic events are less frequent but can be life threatening. The aim of this review is to provide new insights into the pathogenesis of BD. Over the past year substantial advances have been done in the understanding of the genetic [1,2] and immunology [3] of BD. BD is at the crossroad between autoimmune and autoinflammatory syndromes. In common with autoimmune diseases BD shares class I MHC association. However, in contrast to autoimmune disorders, BD has clinical features that seem to be mostly autoinflammatory. The pathogenesis of BD is still unknown, but major determinants of the genetic and immune system abnormalities have been reported recently. Triggering infectious factors are supposed to participate in the outbreak of BD in genetically predisposed patients. Two recent large genome-wide association study (GWAS) conducted in Turkey and Japan reported association between single nucleotide polymorphism (SNP) of interleukin (IL)-10 and IL-23R/IL-12RB2 genes and BD. New insights into the perturbations of T cell homeostasis of BD recently emerged. We have recently demonstrated the promotion of Th17 responses and the suppression of regulatory T cells (Tregs) that were driven by interleukin (IL)-21 production and that correlates with BD activity. Inflammatory cells within BD inflammatory lesions included mostly neutrophils, Th1 and Th17 cells, and cytotoxic CD8+ and γδ T cells. Altogether, the recent progresses in the knowledge of BD pathogenesis pave the way for innovative therapy.

Hepatitis C: viral and host factors associated with non-response to pegylated interferon plus ribavirin

Treatment for chronic hepatitis C virus (HCV) infection has evolved considerably in the last years. The standard of care (SOC) for HCV infection consists in the combination of pegylated interferon (PEG‐IFN) plus ribavirin. However, it only induces a sustained virological response (SVR) in half of genotype 1‐infected patients. Several viral and host factors have been associated with non‐response: steatosis, obesity, insulin resistance, age, male sex, ethnicity and genotypes. Many studies have demonstrated that in non‐responders, some interferon‐stimulated genes were upregulated before treatment. Those findings associated to clinical, biochemical and histological data may help detect responders before starting any treatment. This is a very important issue because the standard treatment is physically and economically demanding. The future of HCV treatment would probably consist in the addition of specifically targeted antiviral therapy for HCV such as protease and/or polymerase inhibitors to the SOC. In genotype 1 patients, very promising results have been reported when the protease inhibitor telaprevir or boceprevir is added to the SOC. It increases the SVR rates from approximately 50% (PEG‐IFN plus ribavirin) to 70% (for patients treated with a combination of PEG‐IFN plus ribavirin plus telaprevir). Different elements are associated with non‐response: (i) viral factors, (ii) host factors and (iii) molecular mechanisms induced by HCV proteins to inhibit the IFN signalling pathway. The goal of this review is to present the mechanisms of non‐response, to overcome it and to identify factors that can help to predict the response to anti‐HCV therapy.

Critical role of IL-21 in modulating TH17 and regulatory T cells in Behçet disease

BACKGROUND Behçet disease (BD) is a chronic systemic inflammatory disorder of unknown etiology. OBJECTIVE To determine the nature of T cells driving inflammatory lesions in BD. METHODS T cell homeostasis and cytokines production were analyzed in peripheral blood and brain inflammatory lesions from 45 adult patients with BD (active and untreated BD [n = 25] and patients in remission [n = 20]) and 20 healthy donors, using Luminex, flow cytometry, immunohistochemistry, and immunofluorescence analysis. RESULTS We found a marked increase in T(H)17 cells and a decrease in the frequency of CD4(+) forkhead box P3(+) regulatory T cells (Tregs) in peripheral blood that were induced by IL-21 production and that correlate with BD activity. The addition of serum from patients with active BD in a sorted CD4(+) T cells culture of healthy donors induced a significant and dose-dependent production of IL-17A and a decrease in forkhead box P3 expression. We demonstrated the presence of IL-21- and IL-17A-producing T cells within the cerebrospinal fluid, brain parenchyma inflammatory infiltrates, and intracerebral blood vessels from patients with active BD and central nervous system involvement. The stimulation of CD4(+) T cells with IL-21 increased T(H)17 and T(H)1 differentiation and decreased the frequency of Treg cells. Conversely, IL-21 blockade with an IL-21R-Fc restored the T(H)17 and Treg homeostasis in patients with BD. CONCLUSION We provided here the first evidence of the critical role of IL-21 in driving inflammatory lesions in BD by promoting T(H)17 effectors and suppressing Treg cells. IL-21 represents a promising target for novel therapy in BD.

Mortality in Behçet's disease

OBJECTIVE To report the long-term mortality in patients with Behçets 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.

Pathogenic T cells have a paradoxical protective effect in murine autoimmune diabetes by boosting Tregs

CD4+CD25+Foxp3+ Tregs play a major role in prevention of autoimmune diseases. The suppressive effect of Tregs on effector T cells (Teffs), the cells that can mediate autoimmunity, has been extensively studied. However, the in vivo impact of Teff activation on Tregs during autoimmunity has not been explored. In this study, we have shown that CD4+ Teff activation strongly boosts the expansion and suppressive activity of Tregs. This helper function of CD4+ T cells, which we believe to be novel, was observed in the pancreas and draining lymph nodes in mouse recipients of islet-specific Teffs and Tregs. Its physiological impact was assessed in autoimmune diabetes. When islet-specific Teffs were transferred alone, they induced diabetes. Paradoxically, when the same Teffs were cotransferred with islet-specific Tregs, they induced disease protection by boosting Treg expansion and suppressive function. RNA microarray analyses suggested that TNF family members were involved in the Teff-mediated Treg boost. In vivo experiments showed that this Treg boost was partially dependent on TNF but not on IL-2. This feedback regulatory loop between Teffs and Tregs may be critical to preventing or limiting the development of autoimmune diseases.

Rituximab combined with Peg-interferon-ribavirin in refractory hepatitis C virus-associated cryoglobulinaemia vasculitis

Objectives: To report the results of a pilot study using rituximab combined with Peg-interferon (IFN) α2b-ribavirin in severe refractory hepatitis C virus (HCV) related mixed cryoglobulinaemia (MC) vasculitis. Methods: Sixteen consecutive patients with severe HCV-MC vasculitis that were resistant (n = 11) or relapser (n = 5) to a previous combination treatment with standard (n = 10) or Peg-IFNα2b (n = 6) plus ribavirin were included. They were treated with rituximab (375 mg/m2 intravenously weekly for 4 weeks) combined with Peg-IFNα2b (1.5 μg/kg per week subcutaneously) plus ribavirin (600–1200 mg/day orally) for 12 months. Results: Fifteen patients (93.7%) showed clinical improvement, 10 of whom (62.5%) were clinical complete responders (CR). HCV RNA and serum cryoglobulin became undetectable in all the clinical CR. Peripheral blood B cell depletion was achieved in all patients (CD19+ cells, 111 (SD 32)/mm3 at baseline versus 2(2)/mm3 after the fourth infusion of rituximab) with reconstitution starting at the end of antiviral treatment. Compared with clinical CR, the partial or non-responders had a 3.6 times longer duration of vasculitis prior to treatment and a lower rate of early virological response. Treatment was well tolerated with no infectious complications. After a mean follow-up of 19.4 (SD 3.6) months, two patients experienced clinical relapse associated with a simultaneous reappearance of HCV RNA and cryoglobulin and an increase in the number of B cells. Conclusions: Rituximab combined with Peg-IFNα2b-ribavirin represents a safe and effective treatment option in severe refractory HCV-MC vasculitis.

Retrospective Analysis of Surgery Versus Endovascular Intervention in Takayasu Arteritis: A Multicenter Experience

Background— With recent advances in endovascular treatment, percutaneous endoluminal angioplasty has become particularly attractive for arterial lesions of Takayasu arteritis. However, data came from case reports or small series, and the long-term outcome has not been reported. The incidence of potential vascular complications after surgery or endovascular treatment is still to be determined. Methods and Results— This retrospective multicenter study analyzed the results and outcomes of 79 consecutive patients with Takayasu arteritis (median age, 39 years; interquartile range [IQR], 25–50 years; 63 women [79.7%]) who underwent 166 vascular procedures (surgery, 104 [62.7%]; endovascular repair, 62 [37.3%]) for the management of arterial complications. After a follow-up of 6.5 years (IQR, 2.2–11.5 years), 70 complications were observed, including restenosis (n=53), thrombosis (n=7), bleeding (n=6), and stroke (n=4). The overall 1-, 3-, 5-, and 10-year arterial complication–free survival rates were 78% (IQR, 69%–88%), 67% (IQR, 57%–78%), 56% (IQR, 46%–70%), and 45% (IQR, 34%–60%), respectively. Among the 104 surgical procedures, 39 (37.5%) presented a complication compared with 31 of the 62 (50%) with endovascular repair. In multivariate analysis, biological inflammation at the time of revascularization (odds ratio, 7.48; 95% confidence interval, 1.42–39.39; P=0.04) was independently associated with the occurrence of arterial complications after the vascular procedure. Patients who experienced complications had higher erythrocyte sedimentation rates (P<0.001) and C-reactive protein (P<0.001) and fibrinogen (P<0.005) serum levels compared with those without complications. Conclusions— The overall 5-year arterial complication rate was 44%. Biological inflammation increased the likelihood of complications after revascularization in patients with Takayasu arteritis.