Role of Ca(2+), Calnexin and Calreticulin in Platelet from Adult Patients with Chronic Immune Thrombocytopenic Purpura

BACKGROUND: Adult chronic immune thrombocytopenia (chronic ITP) is a common autoimmune hemorrhagic disease characterized by decreased platelet production and increased platelet destruction, leading to thrombocytopenia. In this study, Ca(2+), calnexin (CNX) and calreticulin (CRT) within platelets from adult patients with chronic ITP were investigated. METHODS: Platelets were isolated from blood specimen collected from 20 adult patients with chronic ITP and 20 healthy volunteers. Ca(2+), CNX and CRT were determined by flow cytometry, and the results were analyzed with EXPO32 ADC software. RESULTS: Flow cytometry showed the expressions of Ca(2+) (74.19±19.40% vs 22.79±10.47%) was elevated (P<0.05). However, CNX (15.10±7.32% vs 41.79±14.45%) and CRT (25.11±12.66% vs 38.58±12.02%) were decreased markedly in platelets from adult patients with chronic ITP (P<0.05 compared with healthy volunteers). CONCLUSION: Based on enhanced expression of Ca(2+) and attenuated expression of CNX and CRT in patients with chronic ITP, Ca(2+) concentration and its associated down-regulated proteins may be important regulatory signals in the pathogenesis of chronic ITP.