Tacrolimus therapy in primary Sjögren's syndrome with refractory immune thrombocytopenia: a retrospective study.

Objectives: To evaluate the efficacy and safety of tacrolimus (TAC) for the treatment of primary Sjögren's syndrome (pSS) with refractory immune thrombocytopenia (RITP).

Methods: Twenty-three pSS patients with RITP treated with TAC from June 2018 to June 2021 at the First Affiliated Hospital of Soochow University were enrolled in this retrospective cohort study. Platelet response, clinical and immunological parameters, toxicity and safety were compared and analysed at baseline and different points after TAC treatment.

Results: At 4 weeks after treatment, 2 patients (8.7%) attained a complete response (CR, platelet count ≥100×109/L and no bleeding), 15 patients (65.2%) achieved a partial response (PR, platelet count ≥ 30×109/L but <100×109/L and no bleeding or a platelet count at least twice that before treatment), and the other 6 patients (26.1%) did not respond to TAC treatment. At 8 weeks after treatment, a CR was seen in 4 patients (17.4%), and the percentage of patients with a PR increased to 78.3% (18 patients). The percentage of patients with a CR increased to 47.8% (11 patients), and 9 patients (39.1%) achieved a PR without relapse at 12 weeks after treatment. At 24 weeks after treatment, 14 patients (60.9%) achieved a CR, and 8 patients (34.8%) achieved a PR. Compared to before treatment, the level of IgG was decreased significantly at 24 weeks after treatment, whereas there was no significant difference in the levels of IgM or IgA between baseline and 24 weeks after treatment. Additionally, the absolute CD3+ T cell count, European SS Disease Activity Index (ESSDAI) score, and levels of IL-2 and INF-γ were significantly decreased at 24 weeks after treatment.

Conclusions: TAC is effective and well tolerated by pSS patients with RITP, and the mechanism underlying the effect of TAC in these patients may be related to reduced Th1 cytokine expression.