Introduction

Connective tissue diseases (CTDs), which include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS), and so on, represent a group of autoimmune disorders that predominantly affect the body's connective tissues.

Aim

This study aimed to investigate the clinical efficacy of sirolimus in patients with connective tissue disease complicated with refractory thrombocytopenia (CTD-RTP) and its effect on immune regulation.

Material and methods

A retrospective study was conducted on 13 patients diagnosed with CTD-RTP who were treated with oral sirolimus for 6 months, starting with a daily dose of 1 mg. Changes in platelet counts, T cell lymphocyte subsets, regulatory T cells (Tregs), B cells, and cytokine levels were assessed from baseline to the end of the 6-month treatment. From November 2020 to December 2023, 13 patients with CTD-RTP were consecutively enrolled and monitored.

Results

The treatment was well tolerated with no severe drug-related toxicities were reported. After 3 months of sirolimus treatment, 7 patients exhibited a positive response (PR), with 1 patient achieving complete response (CR), resulting in an overall response rate of 61.5%. Continued treatment for 6 months led to further improvements, with the total effective rate reaching 76.9%. Importantly, there was a significant increase in peripheral blood Tregs after treatment compared with the baseline level.

Conclusions

Sirolimus is an effective and safe treatment option for CTD-RTP patients, and its effect may be related to its ability to increase the level of regulatory T cells in peripheral blood.