Plasma P-selectin autoantibodies (A490) in ITP patients, pSS patients with/without thrombocytopenia and healthy controls. Data are expressed as mean ±SD. The plasma P-selectin autoantibodies in ITP patients, pSS patients with thrombocytopenia and pSS patients without thrombocytopenia was significantly higher than in healthy controls (P=0.000, P=0.000 and P=0.024, respectively), but there was no significant difference in the P-selectin autoantibodies between ITP patients and pSS patients with thrombocytopenia (P=0.062).