A histologic hallmark of primary SS (pSS) is lymphocytic infiltration of the salivary and lacrimal glands, in particular by CD4+ T and B cells. In the early stages of the disease, infiltrates are dominated by CD4+ T cells, while B cell accumulation occurs at later stages. Activated T cells contribute to pathogenesis by producing pro-inflammatory cytokines and by inducing B cell activation, which results in the establishment of a positive feedback loop. In the inflamed glandular tissues, many different CD4+ effector subsets are present, including IFN-γ-producing Th1 cells, IL-17-producing Th17 cells and IL-21-producing T follicular helper cells. In blood from pSS patients, frequently observed abnormalities of the T cell compartment are CD4+ T cell lymphopenia and enrichment of circulating follicular helper T (Tfh) cells. Tfh cells are critical mediators of T cell–dependent B cell hyperactivity and these cells can be targeted by immunotherapy. Inhibition of T cell activation, preferably early in the disease process, can mitigate B cell activity and may be a promising treatment approach in this disease.
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机译：原发性 SS （pSS） 的组织学标志是唾液腺和泪腺的淋巴细胞浸润，特别是 CD4+ T 细胞和 B 细胞。在疾病的早期阶段，浸润以 CD4+ T 细胞为主，而 B 细胞积累发生在晚期。活化的 T 细胞通过产生促炎细胞因子和诱导 B 细胞活化来促进发病机制，从而建立正反馈回路。在发炎的腺组织中，存在许多不同的 CD4 + 效应子亚群，包括产生 IFN γ的 Th1 细胞、产生 IL-17 的 Th17 细胞和产生 IL-21 的滤泡辅助性 T 细胞。在 pSS 患者的血液中，经常观察到的 T 细胞区室异常是 CD4+ T 细胞淋巴细胞减少和循环滤泡辅助性 T （Tfh） 细胞富集。Tfh 细胞是 T 细胞依赖性 B 细胞过度活跃的关键介质，这些细胞可以被免疫疗法靶向。抑制 T 细胞活化，最好在疾病过程的早期，可以减轻 B 细胞活性，可能是这种疾病的一种有前途的治疗方法。
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