This study aims to describe patients' characteristics and treatment responses with primary Sjögren's syndrome (pSS) who experience immune thrombocytopenia (ITP) and ITP with clinical significance (ITPCS).

A retrospective study was conducted involving 164 patients diagnosed with pSS-related ITP after excluding secondary ITP. Patients were categorized into subgroups based on the risk of bleeding: major bleeding event (MBG), non-hemorrhagic group (NHG), and hematological involvement-only SS group (HOSG).

57 (34.8%) were diagnosed with ITP simultaneously with pSS, while 60 (36.6%) were diagnosed with ITP before pSS. ITP patients exhibited a high prevalence of interstitial lung disease (19.5%), and an up to 96.3% positive presence of anti-SSA/Ro-52 antibody. ITPCS was identified in 58.5% of patients, with 22.0% experiencing high-risk hemorrhagic events. A median (range) of 2 (1, 3) treatment lines for maintenance therapies were administered. Corticosteroids and hydroxychloroquine (HCQ) led to an ITP response in 76.1% of patients. Ciclosporin A (CsA) and other medicines contributed to a 76.6% response. The MBG, NHG, and HOSG groups consisted of 36 (22.0%), 68 (41.5%) and 53 (32.3%) patients, respectively. Notably, patients of MBG were more frequently diagnosed before SS onset (p = 0.035). They required more treatment lines (p = 0.001) with a lower risk of relapse (p < 0.001), which is confirmed in patients with only hematological involvement (HOSG group).

Patients with pSS-related ITP face an increased risk of bleeding, particularly in the MBG group, which necessitates more extensive treatment. Heterogeneous treatment regimens were observed for pSS-related ITP, and combinations involving corticosteroids, HCQ, and/or CsA appear viable options.