[Polymorphisms of FcγRIIA, FcγRIIIA and FcγRIIB in patients with immune thrombocytopenia and their clinical significance].

This study was aimed to investigate the correlation of FcγR polymorphisms with the susceptibility, severity and efficacy of immunotherapy for patients with immune thrombocytopenia (ITP). PCR and DNA sequencing were used to determine the polymorphisms of FcγRIIA, FcγRIIIA and FcγRIIB in 44 ITP patients, and in 97 healthy control subjects. The results indicated that FcγRIIIA-158V/F polymorphisms between patients and controls were statistically significantly different (P = 0.015); among FcγRIIIA genotypes, the frequency of 158V/V homotype was higher in ITP (P = 0.005). However, the FcγRIIA-131H/R or FcγRIIB-232T/I polymorphisms were not significantly different between patients and controls; there were no correlation of FcγRIIA, FcγRIIIA and FcγRIIB genotype frequencies with the platelet counts or the courses of ITP; among the 38 ITP patients who received treatments, the complete response (CR) rate was 42% (16/38), and partial response (PR) rate was 34% (13/38). The therapeutic response was significantly different between FcγRIIIA-158V/V homotype and 158F/V heterotype (P = 0.034). The CR of patients with 158V/V homotype was obviously lower than that of patients with 158F/V, but the frequencies of FcγRIIA and FcγRIIB genotypes not correlated with the responsiveness to treatment. The CR rate of 6 patients treated with rituximab was 67%, and PR rate was 17%. The overall response rate was as high as 84%, the adverse reactions were not observed. It is concluded that the polymorphism of FcγRIIIA-158V/F, but not FcγRIIA-131H/R or FcγRIIB-232T/I, correlates with the patient susceptibility and therapeutic response of ITP.