Treatment with B cell depletion therapy lowers circulating TFH cells in pSS patients
B cell depletion therapy has decreased the high levels of circulating follicular Th (TFH) cells in patients with primary Sjögren syndrome (pSS), improving the objective clinical disease activity measures, according to a study.
A total of 24 pSS patients treated with rituximab (RTX) and 24 healthy controls were included in this study that evaluated the effect of B cell depletion therapy on effector CD4+ T cell homeostasis and its relation to objective measures of disease activity in pSS patients.
Researchers used flow cytometry to examine the frequencies of circulating effector CD4+ T cell subsets at baseline and at 16, 24, 36 and 48 weeks after the first RTX infusion. Based on surface marker expression patterns, Th1, Th2, Th17 and TFH cells were discerned.
In addition, researchers conducted intracellular cytokine staining for interferon-y, interleukin (IL)-4, IL-21 and IL-17, and analysed serum levels of these cytokines.
There were increased frequencies of circulating TFH and Th17 cells in patients with pSS at baseline compared with controls, but the Th1 and Th2 cell frequencies were unchanged.
There was a noticeable reduction in circulating TFH cells in patients who received B cell depletion therapy. On the other hand, Th17 cells were only slightly reduced. There were also reductions in frequencies of IL-21– and IL-17–producing CD4+ T cells, as well as serum levels of IL-21 and IL-17.
An association was found between the reduction in circulating TFH cells and 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.
According to researchers, these observations demonstrated the essential role of the crosstalk between B cells and TFH cells in the pathogenesis of pSS.