RT Journal Article SR Electronic T1 B Cell Depletion Therapy Normalizes Circulating Follicular Th Cells in Primary Sjögren Syndrome JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 49 OP 58 DO 10.3899/jrheum.160313 VO 44 IS 1 A1 Gwenny M. Verstappen A1 Frans G.M. Kroese A1 Petra M. Meiners A1 Odilia B. Corneth A1 Minke G. Huitema A1 Erlin A. Haacke A1 Bert van der Vegt A1 Suzanne Arends A1 Arjan Vissink A1 Hendrika Bootsma A1 Wayel H. Abdulahad YR 2017 UL http://www.jrheum.org/content/44/1/49.abstract AB Objective. To assess the effect of B cell depletion therapy on effector CD4+ T cell homeostasis and its relation to objective measures of disease activity in patients with primary Sjögren syndrome (pSS).Methods. Twenty-four patients with pSS treated with rituximab (RTX) and 24 healthy controls (HC) were included. Frequencies of circulating effector CD4+ T cell subsets were examined by flow cytometry at baseline and 16, 24, 36, and 48 weeks after the first RTX infusion. Th1, Th2, follicular Th (TFH), and Th17 cells were discerned based on surface marker expression patterns. Additionally, intracellular cytokine staining was performed for interferon-γ, interleukin (IL)-4, IL-21, and IL-17 and serum levels of these cytokines were analyzed.Results. In patients with pSS, frequencies of circulating TFH cells and Th17 cells were increased at baseline compared with HC, whereas frequencies of Th1 and Th2 cells were unchanged. B cell depletion therapy resulted in a pronounced decrease in circulating TFH cells, whereas Th17 cells were only slightly lowered. Frequencies of IL-21–producing and IL-17–producing CD4+ T cells and serum levels of IL-21 and IL-17 were also reduced. Importantly, the decrease in circulating TFH cells was associated with lower systemic disease activity over time, as measured by the European League Against Rheumatism Sjögren’s Syndrome Disease Activity Index scores and serum IgG levels.Conclusion. B cell depletion therapy in patients with pSS results in normalization of the elevated levels of circulating TFH cells. This reduction is associated with improved objective clinical disease activity measures. Our observations illustrate the pivotal role of the crosstalk between B cells and TFH cells in the pathogenesis of pSS.