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• The double negative T cells in patients with AAV were amplified. • More CD62L-CD45RO- double negative T cells in patients with AAV. • Double negative T cells produced IFN-γ, IL-4 and IL-17 in patients with AAV. • Expanded double negative T cells in patients with AAV and renal vasculitis. • Conventional methylprednisolone effectively reduced double negative T cells. CD3+CD4−CD8− [double-negative (DN)] T cells play vital roles in the pathogenesis of autoimmune disorders. In this study, we investigated the exact level of DN T cells in patients with antineutrophil cytoplasmic autoantibody (ANCA)–associated vasculitis (AAV). Forty patients with active AAV and 19 healthy controls (HCs) were enrolled in this study. Peripheral mononuclear cells were characterised phenotypically via flow cytometry. The potential clinical value of DN T cells was then assessed by the receiver operating characteristic (ROC) curves. The percentage (p < 0.001) and absolute number (p = 0.028) of DN T cells were found to be significantly higher in patients with AAV than in HCs. Relative to HCs, a lower percentage of DN T cells from patients with AAV was of the CD62L+CD45RO+ phenotype (p = 0.024), a higher percentage of these cells was of the CD62L–CD45RO– phenotype (p = 0.043). Patients with AAV had increased percentages of DN T cells expressing interferon (IFN)-γ (p = 0.032), interleukin (IL)-4 (p = 0.039) and IL-17 (p = 0.042). Furthermore, the percentages of IL-17–producing CD4+ T cells and IFN-γ–producing CD8+ T cells were significantly higher in patients with AAV than in HCs (p = 0.014, p = 0.008). Compared with the CD4+ and CD8+ T-cell subsets, DN T cells had the highest fractions of intracellular IL-17 in HCs and patients with AAV (both p < 0.001). In patients with AAV and renal damage, the percentage of DN T cells was expanded relative to that in patients without renal damage (p = 0.016). In addition, conventional methylprednisolone effectively reduced the percentage and overall number of DN T cells in patients with AAV (p = 0.028, p = 0.007). DN T cells represent a T-lymphocyte subset that produces inflammatory cytokines (IFN-γ, IL-4 and IL-17) and is absolutely elevated in patients with AAV. Additional investigations are required to determine their precise role in patients with AAV. [ABSTRACT FROM AUTHOR]

Dermatomyositis (DM) is closely associated with infection, the levels of peripheral lymphocyte subpopulations are rarely studied in patients with DM combined with Epstein-Barr virus (EBV)/cytomegalovirus (CMV) infection. Here, we aimed to observe the level of lymphocyte subsets, especially Th17, regulatory T (Treg) cells in DM combined with EBV/CMV viremia, and explore the effects of short-term low-dose IL-2. 34 DM patients combined with EBV/CMV viremia (DM infection group), 31 DM patients without infection (DM non-infection group) and 20 healthy controls were entrolled in our study. In DM infection group, 13 patients received low-dose IL-2 at 0.50 Million IU/day for a five-day course on the basis of conventional treatment. All subjects had completed the decetion of the absolute numbers of lymphocytes subsets in peripheral blood by flow cytometry. The infection group had significant decreases levels of total T, total B, NK, CD4 + T cells and CD4 + T subsets (Th1, Th2, Th17, Treg cells). Compare to the healthy controls, Th17 cells was significantly reduced in the infection group, but not in the non-infection group (P < 0.001 vs. P = 0.171). After low-dose IL-2 therapy, the levels of Treg (P = 0.001) cells and Th17 cells were significantly elevated, re-balancing the Th17 and Treg proportions. The absolute numbers of Th17 and Treg cells in DM patients with EBV/CMV viremia is further reduced. In addition to Treg cells, a decrease in Th17 cells may be also a crucial feature. Low-dose IL-2 treatment may be beneficial and safe prospect immunomodulatory therapy to restores imbalance between Th17 and Treg cells for these patients. Low-dose IL-2 therapy may be a new prospect field with some challenges such as long-term immunoregulatory utility in various virus infection. [ABSTRACT FROM AUTHOR]

The breakdown of immune tolerance mediated by the reduced regulatory T (Treg) cell contributes to autoimmune diseases, which can be recovered by the short-term and low-dose interleukin 2 (IL-2). However, the role of Treg cells in microscopic polyangiitis (MPA) and the efficacy of short-term and low-dose IL-2 for MPA remain unclear. Therefore, we performed a retrospective study to explore the role of Treg cells and evaluate the efficacy of short-term and low-dose IL-2 therapy in MPA. 52 MPA were collected as research objects, and 15 of them voluntarily received short-term and low-dose IL-2 subcutaneous injection combined with conventional therapy. 60 volunteers were recruited as health controls (HC) according to the inclusion and exclusion criteria. The number of circulating CD4 + T cell subsets was detected by flow cytometry. Patients with MPA had reduced circulating Treg cells than HCs (P < 0.001), and the level of Treg cells were reduced in MPA-activity and ANCA-positive group (P = 0.018 and P = 0.008 respectively). The patients with lower Treg cells had the higher incidence of the organ involvement (P = 0.006). The level of Treg cells in MPA was doubled after the short-term and low-dose IL-2 combined with conventional therapy (P = 0.001), and the disease activity indicators such as ESR and CRP were improved (P < 0.05) with no apparent side effects. Patients with MPA had reduced circulating Treg cells, especially the MPA-activity and ANCA-positive patients. And the patients with lower Treg cells were more likely to exhibit the organ involvement. Short-term and low-dose IL-2 therapy increased the reduced Treg cells and promoted the remission of the disease at a certain extent with well tolerance. [ABSTRACT FROM AUTHOR]