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Mixed cryoglobulinemic vasculitis is associated with monoclonal B cell expansion in patients with chronic hepatitis C (HCV) infection. B cell depletion therapy using rituximab, a CD20 monoclonal antibody, has been successful in achieving remission from symptomatic disease. This study investigated whether B cell depletion therapy has an impact on activation of HCV-specific T cell phenotype and function. Nineteen patients with Hepatitis C mixed cryoglobulinemic vasculitis were treated with 4 cycles of rituximab (375 mg/m 2 ) and variables were measured 6 months after therapy. Using flow cytometry and Enzyme-Linked Immunospot assay, the number of activated and tissue-like B cells and number of T cells expressing Programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), and multiple cytokines were measured before and after rituximab therapy. B cell depletion therapy is associated with a significant (P < 0.0001) decline in peripheral T cells with exhaustive phenotype, from pre-therapy to post-therapy-of rituximab (mean ± standard error): CD4+ (16.9 ± 0.9% to 8.9 ± 1.0%) and CD8+ (6.8 ± 0.6% to 3.0 ± 0.5%) T cells expressing PD-1 and CD4+ (11.0 ± 1.0% to 6.1 ± 0.8%) and CD8+ (12.7 ± 0.7% to 6.4 ± 0.4%) T cells expressing TIM-3. In addition, there was a significantly higher percentage of peripheral CD8+ T cells responding to HCV peptide stimulation in vitro secreting IFN-γ (4.55 ± 0.3 to 9.6 ± 1.0 IFN-γ/10 6 PBMCs, P < 0.0001), and more than one cytokine (1.3 ± 0.1% to 3.8 ± 0.2%, P < 0.0001) after therapy compared to pre-therapy. B cell depletion therapy results in recovery of T cell exhaustion and function in patients with HCV cryoglobulinemic vasculitis., (© 2017 Wiley Periodicals, Inc.)

B cell depletion therapy using rituximab has been shown to be effective in achieving remission in patients with HCV-mixed cryoglobulinemic (MC) vasculitis. Previously, we have demonstrated abnormalities in peripheral immune cells involving neutrophils, chemotaxis, and innate immune activation among patients with HCV-MC vasculitis when compared to HCV patients without vasculitis. In this study, we evaluated the effect of B cell depletion therapy on transcriptional profiles of peripheral blood mononuclear cells before and after riruximab therapy, in order to unravel the pathogenic mechanism involved in HCV-MC vasculitis induced by abnormal B cell proliferation. DNA microarray analysis was performed using RNA from PBMCs from seven patients with HCV-MC vasculitis and seven normal volunteers. DNA was hybridized to Affymetrix U133A chips. After normalization, differentially expressed gene list with treatment was generated using partitional clustering. RT-PCR, flow cytometry, and enzyme immunoassay (EIA) was used to validate DNA microarray findings. Differentially expressed genes included B cells and non-B cell genes. Validation of genes using purified cell subsets demonstrated distinct effect of B cell depletion therapy on non-B cells, such as monocytes, T cells, and NK cells. Notably, B lymphocyte stimulator (BLyS) levels were persistently elevated in patients who subsequently relapsed. In conclusion, pathogenesis of HCV-MC vasculitis is mediated by abnormal proliferation of B cells, driven by BLyS, leading to significant effects on non-B cells in mediating symptomatology. Future therapeutics using a combination approach of B cell depletion and proliferation may be desired to achieve long-term remission.

Mixed cryoglobulinemic vasculitis is associated with the monoclonal expansion of pathognomonic B cells in chronic hepatitis C. Recently, treatment with B-cell depletion, including rituximab, a CD20 monoclonal antibody, has been successful in achieving remission from the active disease. We investigated whether B-cell depletion therapy has an impact on activation of non-B cells in the periphery. Results demonstrated that B-cell depletion therapy is associated with a statistically significant decline in activated T cells, from pretherapy to follow-up while on rituximab therapy: CD4+ CD38+ HLA-DR+ (DR+), CD8+ CD38, CD8+ CD38+ DR+, and CD8+ DR+. Birmingham Vasculitis Activity Score and cryoglobulin had a strong correlation coefficient (R) of 0.72 (P=.0005), while cryoglobulin showed moderate correlation with CD8+ DR+ (R=.61), CD3+ CD38+ DR+ (R=.57), CD3+ DR+ (R=.50), CD4+ CD38+ DR+ (R=.53), CD4+ DR+ (R=.52), and CD8+ CD38+ DR+ (R=.67). These results suggest B-cell expansion has a direct and indirect effect on the pathogenesis of Hepatitis C-associated mixed cryoglobulinemic vasculitis., (© 2016 John Wiley & Sons Ltd.)

When cytotoxic agents were introduced, their ability to disrupt nucleic acid and protein synthesis led to their effective use for the treatment of neoplastic disease. During the course of this use, however, it became apparent that these agents also suppress the immune system. This usually unwelcome effect was subsequently studied and beneficially directed toward the treatment of non-neoplastic diseases in which autoimmune mechanisms were considered important to pathogenesis. As a result of these investigations, cytotoxic agents and, more recently, cyclosporine have emerged to become an important part of the therapeutic regimen for many autoimmune diseases. Nonetheless, these medications may still cause treatment-induced illness or even death. It is therefore particularly important to weigh the benefits and risks of cytotoxic therapy when treating a non-neoplastic disease. This two-part Clinical Staff Conference reviews data on the efficacy and toxicity of cytotoxic drugs and cyclosporine in selected autoimmune diseases. In part 2, we focus on the role of these agents in treating inflammatory bowel disease and systemic vasculitis and review the toxic effects of these agents.

Infection continues to be a major cause of morbidity and mortality in patients with systemic vasculitis. The recognition and treatment of infections in these patients is a particularly difficult task because the spectrum of potential pathogens is broad and the clinical manifestations of infection often mimic those of the underlying disease. This article provides 1) a general overview of the immunosuppressive properties of agents commonly used in the treatment of systemic vasculitis, and 2) a framework for the diagnostic evaluation and treatment of various infectious syndromes in patients with systemic vasculitis.

With the opportunity for long-term follow-up, it has been appreciated that disease severity may vary considerably in patients with Wegener's granulomatosis, polyarteritis nodosa, microscopic polyangiitis, and Churg-Strauss syndrome. Although combined therapy with cyclophosphamide and glucocorticoids continues to be the foundation of treatment, concerns have increased about the toxicities of this regimen. As illustrated by studies on Wegener's-related subglottic stenosis and endobronchial involvement, it has also become apparent that some disease manifestations may not respond to this therapy. Recent therapeutic investigations have therefore focused on identifying approaches that are less toxic and that are based on anatomic involvement and disease severity. The study of polyarteritis nodosa has additionally been affected by proposed changes in classification that would make this condition a separate entity from microscopic polyangiitis. As progress is made in defining the clinical significance of this nomenclature, the prognostic factors in these patients have also been examined, which may be helpful in guiding therapeutic decisions.

The pathogenesis of vasculitis is complex and involves a variety of mechanisms acting in concert to bring about necrotizing inflammation of blood vessel walls. In recent years, there has been considerable progress in dissecting the immunologic abnormalities present in specific vasculitis syndromes. The primary immunopathogenic events that initiate the process of vascular inflammation and blood vessel damage, however, are still largely unknown. Although the cause of most vasculitis syndromes remains a mystery, advances in molecular and cellular immunology have defined many of the effector mechanisms that mediate inflammatory vascular damage. In this regard, modulation of the inflammatory response by specific cytokine and adhesion molecule antagonists is now possible and may prove beneficial in the treatment of vasculitis.

We examined the cell-surface expression of chemokine and natural killer (NK) cell inhibitory receptors (iNKRs) on NK cells from individuals with human immunodeficiency virus (HIV) infection, chronic hepatitis C infection, and Wegener's granulomatosis (WG), an inflammatory, granulomatous vasculitis. The expression of CCR5 on NK cells was up-regulated in individuals with HIV viremia and in individuals with active WG, indicating that expression of this receptor is modulated by states of immune activation associated with viral infection and inflammatory or immune-mediated diseases. In contrast, iNKRs were shown to be up-regulated only on NK cells of individuals with HIV viremia, and they returned to a normal level when viremia was controlled with effective antiviral therapy. In individuals with HIV-1 viremia, there was a direct correlation between the level of expression of p58.1, p58.2, and CD94 receptors and plasma HIV viremia, suggesting that ongoing active HIV replication has an effect on the expression of such receptors on NK cells. These results suggest that immune activation leads to abnormal cell-surface expression of chemokine receptors on NK cells, whereas HIV-specific processes account for the up-regulation of iNKRs on NK cells; this may explain the NK cell—functional defects seen in HIV infection. [ABSTRACT FROM AUTHOR]