Brief Report: Spatial Heterogeneity of Systemic Sclerosis in France: High Prevalence in the Northeast Region.

OBJECTIVE: Alsace is a region in eastern France with a population of ∼2 million. All residents have high access to health care and an accredited referral center for SSc. Seeking care outside of this region is difficult because of the peculiar geography. The aim of this study was to assess the prevalence and spatial variation of systemic sclerosis (SSc) in eastern France. METHODS: Data for SSc patients were obtained from 3 sources (all general practitioners and community specialists, capillaroscopy centers, and all public and private hospital records) and were used to estimate the prevalence of SSc. Surviving patients who resided in Alsace on January 1, 2008 and fulfilled the American College of Rheumatology and/or the LeRoy and Medsger criteria were included in this study. The clinical characteristics of the patients were also assessed. Potentially incomplete case ascertainment was corrected by capture-recapture analyses. Geographic disparities were assessed by spatial cluster analysis and by comparing our results with those for other geographic areas in the world for which data derived using similar methodology were available. RESULTS: The review of 499 potential cases identified a total of 244 SSc patients. A trend toward a west-to-east gradient was observed but did not reach statistical significance. According to log-linear modeling, an estimated 83.87 additional cases were missed. Thus, the SSc prevalence was 228.42 cases per million adult inhabitants of Alsace (95% confidence interval 203.70-253.14); this prevalence was significantly higher than that in 2 other regions of France and comparable with the reported prevalence in Detroit, Michigan. CONCLUSION: The stringent methodology used in the current study is very likely to provide an accurate estimation of the prevalence of SSc. Design similarity with 3 other surveys extends the scope of the results by identifying geographic disparities that were previously indistinguishable due to methodologic differences.

Rituximab treatment overcomes reduction of regulatory iNKT cells in patients with rheumatoid arthritis.

Invariant natural killer T (iNKT) cells are a subset of T cells that recognize glycolipid antigens presented by the CD1d molecule. Accumulating evidences showed that iNKT cells are implicated in the regulatory mechanisms that control autoimmunity. We evaluated the number of circulating iNKT cells in patients with rheumatoid arthritis (RA) by flow cytometry and performed a longitudinal analysis of iNKT cell frequency in RA patients who were given an anti-CD20 therapy. Significantly lower iNKT cell numbers were measured in the blood from RA patients compared to healthy individuals (p<0.0001) and low iNKT cell frequencies were rather associated with an active disease. In RA patients who received rituximab treatment, iNKT cell number was increased in relation to the clinical outcome. We demonstrated that the number of iNKT cells is altered in RA patients and that following rituximab therapy, clinical remission of RA is associated with an increase of iNKT cell frequency.

Incidence and prevalence of systemic sclerosis: a systematic literature review.

OBJECTIVES: To determine the incidence and prevalence of systemic sclerosis (SSc) in adults, its epidemiological tendencies over time, and its possible key determinants. METHODS: We performed a systematic literature review using the keywords "systemic sclerosis," "incidence," "prevalence," and "epidemiology." RESULTS: We found 32 articles published from 1969 to 2006 in which the prevalence of SSc ranged from 7/million to 489/million and its incidence from 0.6/million/y to 122/million/y. There were many geographical variations: SSc prevalence was higher in the USA (276/million in 1990) and Australia (233/million in 1999) than in Japan and Europe, where a north-south gradient was also observed (France: 158/million in 2001 and England: 88/million in 2000). In some regions (Ontario, Rome, near London's airports) there was an unusually high number of SSc cases (3, 5, or 1000 times greater than expected), suggesting spatiotemporal clustering, although no key determinants could be identified. Furthermore, there seemed to be a trend toward an increase in the incidence of SSc over time, but this tendency is uncertain due to lack of uniformity in study methods and designs. We also found that susceptibility to the disease differed according to sex, age, and race. CONCLUSION: Uniform clinico-epidemiological studies with standard diagnostic and classification criteria are needed to refine the epidemiological features of SSc. Homogeneous study methods with exhaustive case ascertainment as seen in a "capture-recapture" analysis will also be necessary to obtain reliable data.

Regulatory T cells and systemic lupus erythematosus.

Regulatory T cells, especially CD4+CD25+ T cells, "natural killer" T cells and gammadelta T cells, are central in the maintenance of peripheral tolerance and the protection from the development of autoimmune diseases. Numerical or functional modifications of these cell populations were demonstrated to lead to the breakdown of tolerance and the emergence of autoimmunity. Involvement of regulatory T cells in the pathogenesis of systemic autoimmune diseases, such as systemic lupus erythematosus, might be of first importance. In murine models and patients with lupus, these regulatory T cells seem to be reduced in number. Functional deficiencies have also been described in a few studies. A better knowledge of regulatory T cell functional properties in systemic autoimmune diseases is essential to manipulate these cells and hopefully to restore immune tolerance.