ObjectiveTo compare response to rituximab (RTX) between adult patients positive for myelin oligodendrocyte glycoprotein (MOG) and aquaporin‐4 (AQP4) antibodies.MethodsWe prospectively studied adult patients with MOG or AQP4 antibodies who received RTX under an individualized dosing schedule adapted to the biological effect of RTX monitored by memory B‐cell measurement. Memory B cells were counted monthly and when relapse occurred. The biological effect of RTX was considered significant with <0.05% memory B cells in peripheral blood lymphocytes.ResultsIn 16 patients with MOG antibodies and 29 with AQP4 antibodies, mean follow‐up was 19 (range = 9–38) and 38 (13–79) months. Under RTX, 10 relapses occurred in 6 of 16 (37.5%) patients with MOG antibodies, and 13 occurred in 7 of 29 (24%) with AQP4 antibodies. The median time of relapse after the most recent infusion was 2.6 (0.6–5.8) and 7 (0.8–13) months, respectively (p < 0.001). Memory B cells had reemerged in 2 of 10 (20%) relapses in patients with MOG antibodies and 12 of 13 (92.5%) with AQP4 antibodies (p < 0.001).InterpretationIn AQP4 antibody–associated disorder, relapse mostly occurs when the biological effect of RTX decreases, which argues for treatment efficacy. In MOG antibody–associated disorder, the efficacy of RTX is not constant, because one‐third of patients showed relapse despite an effective biological effect of RTX. In this subpopulation, memory B‐cell depletion was unable to prevent relapse, which was probably caused by different immunological mechanisms. These findings should be used to improve treatment strategies for MOG antibody–associated disorder. ANN NEUROL 2020;87:256–266

Tat is a viral protein secreted from HIV infected cells and extra cellular Tat is suspected to prevent destruction of HIV infected cells from cells of the cellular immunity. The effect of anti retroviral therapy (ART) on Tat secretion has never been investigated. In this study, we tested for antibody reactivity against Tat variants representative of the main HIV subtypes in HIV positive patients receiving ART with undetectable viral loads ( < 40 copies/mL) over the course of one year with a blood sampling every three months. For each of theses five blood sampling, an average of 50 % of patients had Anti-Tat IgG, it turned out that 86% of patients could recognize Tat at least in one blood sampling during the course of the study. Amazingly, anti-Tat IgG appeared and/or disappeared in 66 % of patients. Only 20% had anti-Tat IgG remaining persistently while 14% were consistently without anti Tat IgG in the five blood sampling. No significant correlation was found between anti-Tat IgG and CD4+ T cell, CD8+ T cell and B cell counts revealing the incapacity of these anti Tat IgG to neutralize extra cellular Tat. Interestingly the absence and then the appearance of anti-Tat IgG in patients suggest the presence of HIV infected cells in the blood that may constitute a significant reservoir of HIV infected cells. As a conclusion antiretroviral therapy does not block the secretion of Tat and may explain why HIV infected cells can survive in spite of an effective ART treatment.

SUMMARYHIV infection is associated with cytokine production by monocytes and expansion of a monocyte subset that expresses high levels of CD16. Our study was designed to investigate the effects of anti-retroviral therapies on these immune parameters. Four groups of HIV 1 patients were included in the study. The first group comprised drug-naive patients (n 20); the second included patients who received two inhibitors of HIV reverse transcriptase (n 45); the third group received a therapy combining these two inhibitors and one inhibitor of HIV protease (HAART) (n 35); the fourth consisted of patients who had stopped their treatment (n 20). The release of inflammatory cytokines (tumour necrosis factor, IL-1b , IL-6) and immunoregulatory cytokines such as IL-10 by monocytes was determined by ELISA. The monocyte subsets expressing low or high levels of CD16 were studied by flow cytometry. Monocytes from patients naive of treatment released higher amounts of inflammatory cytokines and IL-10 than HIV 2 individuals. Each anti-retroviral therapy restored a normal pattern of cytokine secretion. Nevertheless, the release of cytokines increased again after the arrest of the treatment. The expansion of the monocyte subset that expresses high levels of CD16 was significantly decreased by HAART but not by the treatment including two inhibitors of reverse transcriptase. These results suggest that only HAART controls monocyte activation in the treatment of HIV infection.

We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter‐individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK‐type lymphoproliferative disease of granular lymphocytes (NK‐LDGL). Alterations of the KIR repertoire were noted in all NK‐LDGL patients. NK cell expansions were classified as oligoclonal KIR+ or as non‐detectable KIR (ndKIR) using anti‐KIR2DL1/2DS1, anti‐KIR2DL2/2DL3/2DS2, anti‐KIR3DL1 and anti‐KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56bright NK cell subset was a constant feature of NK‐LDGL. Altered distribution of CD94+, CD161+, and CD162R+ NK cell subsets was also observed in NK‐LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus‐infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation.