No abstract

We conducted a double-blind, placebo-controlled, randomized study of 3-month treatment with lymecycline, a form of tetracycline, in reactive arthritis (ReA). Lymecycline therapy significantly decreased the duration of the illness in patients with Chlamydia trachomatis-triggered ReA, but not in other ReA patients. In 2 ReA patients, C trachomatis was found in the throat, an uncommon locale for this organism. Our results suggest that it is important to verify the triggering microbe and that it is beneficial to treat Chlamydia arthritis patients with a prolonged course of tetracycline.

Somatic mutations contribute to tumorigenesis. Although these mutations occur in all proliferating cells, their accumulation under non-malignant conditions, such as in autoimmune disorders, has not been investigated. Here, we show that patients with newly diagnosed rheumatoid arthritis have expanded CD8+ T-cell clones; in 20% (5/25) of patients CD8+ T cells, but not CD4+ T cells, harbour somatic mutations. In healthy controls (n=20), only one mutation is identified in the CD8+ T-cell pool. Mutations exist exclusively in the expanded CD8+ effector-memory subset, persist during follow-up, and are predicted to change protein functions. Some of the mutated genes (SLAMF6, IRF1) have previously been associated with autoimmunity. RNA sequencing of mutation-harbouring cells shows signatures corresponding to cell proliferation. Our data provide evidence of accumulation of somatic mutations in expanded CD8+ T cells, which may have pathogenic significance for RA and other autoimmune diseases.