Objective B cells are likely to contribute to the pathogenesis of systemic lupus erythematosus (SLE), and rituximab induces depletion of B cells. The Exploratory Phase II/III SLE Evaluation of Rituximab (EXPLORER) trial tested the efficacy and safety of rituximab versus placebo in patients with moderately-to-severely active extrarenal SLE. Methods Patients entered with ≥1 British Isles Lupus Assessment Group (BILAG) A score or ≥2 BILAG B scores despite background immunosuppressant therapy, which was continued during the trial. Prednisone was added and subsequently tapered. Patients were randomized at a ratio of 2:1 to receive rituximab (1,000 mg) or placebo on days 1, 15, 168, and 182. Results In the intent-to-treat analysis of 257 patients, background treatment was evenly distributed among azathioprine, mycophenolate mofetil, and methotrexate. Fifty-three percent of the patients had ≥1 BILAG A score at entry, and 57% of the patients were categorized as being steroid dependent. No differences were observed between placebo and rituximab in the primary and secondary efficacy end points, including the BILAG-defined response, in terms of both area under the curve and landmark analyses. A beneficial effect of rituximab on the primary end point was observed in the African American and Hispanic subgroups. Safety and tolerability were similar in patients receiving placebo and those receiving rituximab. Conclusion The EXPLORER trial enrolled patients with moderately-to-severely active SLE and used aggressive background treatment and sensitive cutoffs for nonresponse. No differences were noted between placebo and rituximab in the primary and secondary end points. Further evaluation of patient subsets, biomarkers, and exploratory outcome models may improve the design of future SLE clinical trials.

Microparticles (MP) are small membrane‐bound vesicles that circulate in the peripheral blood and play active roles in thrombosis, inflammation and vascular reactivity. While MP can be released from nearly every cell type, most investigation has focused on MP of platelet, leucocyte and endothelial cell origin. Cells can release MP during activation or death. Flow cytometry is the usual method to quantify MP; the small size of these structures and lack of standardization in methodology complicate measurement. As MP contain surface and cytoplasmic contents of the parent cells and bear phosphatidylserine, antibodies to specific cell surface markers and annexin V can be used for identification. Through various mechanisms, MP participate in haemostasis and have procoagulant potential in disease. MP contribute to inflammation via their influence on cell–cell interactions and cytokine release, and MP also function in mediating vascular tone. In several disease states characterized by inflammation and vascular dysfunction, MP subpopulations are elevated, correlate with clinical events, and may have important roles in pathogenesis. In the rheumatic conditions such as rheumatoid arthritis and systemic lupus erythematosus, MP are potentially important markers of disease activity and have an increasingly recognized role in immunopathogenesis. It is clear that MP play an important role in atherosclerosis, and study of these structures may provide insight into the link between chronic inflammatory conditions and accelerated atherosclerosis. As biomarkers, MP allow access to usually inaccessible tissues such as the endothelium. Further research will hopefully lead to interventions targeting MP release and function.

Objective. Nephrogenic fibrosing dermopathy (NFD) is a newly recognized cutaneous fibrotic disorder occurring in individuals with end-stage renal disease (ESRD).The aim of the present study was to describe the clinical and histopathologic features of 9 new cases and to characterize the inflammatory cells and expression of transforming growth factor ␤1 (TGF␤1) in affected skin.Methods. Clinical and laboratory assessments, including serology and pulmonary function studies, were performed in 9 patients undergoing long-term dialysis (8 hemodialysis; 1 peritoneal dialysis) for ESRD of diverse etiologies. Skin, fascia, striated muscles, lungs, and heart were examined by histopathology. Inflammatory cells were characterized by immunophenotyping using specific monoclonal antibodies. TGF␤1 expression was determined by in situ hybridization.Results. All patients displayed cutaneous features resembling both systemic sclerosis and diffuse fasciitis, with severe loss of motion and flexion contractures in multiple joints. Six patients displayed woody induration of the muscles of the legs, thighs, and forearms. Five of the 6 patients with lung involvement had a reduced diffusion capacity for carbon monoxide on pulmonary function testing. Marked elevations of the erythrocyte sedimentation rate and/or C-reactive protein level were found in 6 patients. Antinuclear antibodies were present at low titers in 4 patients. Histopathologic studies indicated that in addition to the dermis, the fibrotic process affected the subcutaneous tissue, fascia, striated muscles, lungs, and myocardium. Large numbers of CD68؉/factor XIIIa؉ dendritic cells and increased expression of TGF␤1 were found in affected skin and muscle.Conclusion. Our findings indicate that the fibrotic process of NFD affects not only the dermis, but also the subcutaneous tissues, fascia, and other organs, including striated muscles, heart, and lungs. We therefore believe this is a systemic fibrosing process, and we suggest that dialysis-associated systemic fibrosis would be a better term for the condition.Nephrogenic fibrosing dermopathy (NFD) is a newly recognized cutaneous fibrotic disorder occurring in individuals with end-stage renal disease (ESRD) (1,2). With a few exceptions, the nearly 100 patients described to date were undergoing long-term hemodialysis or peritoneal dialysis and many had received kidney transplants. Although the etiologic factor(s) responsible for NFD is not known, renal insufficiency and dialysis appear to be intimately involved (for review, see ref.3).Initially, this fibrotic process was considered a form of scleromyxedema (1); however, subsequent studies indicated that the disease was unique (2). The histopathologic changes in affected skin included Dr. Jiménez's work was supported by NIH grant AR-19161.

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