The clinical significance of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody and platelet glycoprotein IIb/IIIa in patients with primary immune thrombocytopenia

OBJECTIVES: The objective of the study is to evaluate the possible roles of the detection of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody, platelet glycoprotein IIb/IIIa, and anti-glycoprotein IIb/IIIa antibody in the diagnosis of primary immune thrombocytopenia (ITP) patients. METHODS: Circulating B cells secreting anti-glycoprotein IIb/IIIa antibody, platelet glycoprotein IIb/IIIa and anti-glycoprotein IIb/IIIa antibody in 64 patients with ITP, 33 non-ITP patients, and 32 controls were measured with enzyme-linked immunospot assay (ELISPOT), monoclonal antibody immobilization of platelet antigens assay (MAIPA) and flow cytometic analysis (FCM), respectively. RESULTS: Compared with the controls and non-ITP patients, the frequency of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody was significantly increased, whereas the positive rate of platelet glycoprotein IIb/IIIa was significantly decreased (P < 0.05) in ITP patients, respectively. The sensitivities for the diagnosis of ITP of ELISPOT and FCM were 68.8% and 57.8%, and the specificities of 90.9% and 90.9%, respectively. The sensitivities of ELISPOT and FCM were higher than MAIPA's sensitivity (39.1%) (P < 0.05). However, there was no apparent difference of the sensitivities of ELISPOT and FCM and the specificities of those three detections (MAIPA's specificity was 81.8%) (P > 0.05). DISCUSSION: ELISPOT and FCM for detecting the circulating B cells secreting anti-glycoprotein IIb/IIIa antibody and the platelet glycoprotein IIb/IIIa were as specific as that of MAIPA for assay of anti-glycoprotein IIb/IIIa antibody, but ELISPOT and FCM had higher sensitivities. So ELISPOT and FCM were sensitive and specific for identifying patients with autoantibody-mediated thrombocytopenia and these should be used as diagnostic tests in clinic.