특발성혈소판감소증에서 FcγRIIIa 수용체 다형성의 임상적 의의

Abstract

Purpose: The FcγRIIIa receptor, one of the low-affinity immunoglobulin (Ig) receptors, plays an important role in the clearance of autoantibody-sensitized platelets, which is one of the major pathogenetic mechanisms of idiopathic thrombocytopenic purpura (ITP). The polymorphism of FcγRIIIa receptors affects the binding affinity of the receptors to the Fc portion of IgG. The purpose of this study is to find out the clinical significance of FcγRIIIa gene polymorphism in ITP. Methods: The genomic DNA was extracted from whole blood of 44 ITP patients and 28 healthy control subjects. The allele specific polymerase chain reaction (PCR) was performed for the FcγRIIIa-176V/F polymorphism determination. The clinical significance of FcγRIIIa genotypes were analysed. Results: There were no significant difference in the platelet count, hemoglobin level and white blood cell count between acute and chronic ITP patients at initial presentation. The frequency of FF, FV, VV polymorphisms were 9, 14, 5 cases in control group, 10, 3, 0 cases in acute ITP, and 14, 28, 2 cases in chronic ITP, respectively. The frequency of FF polymorphism was higher in acute ITP than in control group or chronic ITP (P＜0.05). The acute ITP patients with FV polymorphism tend to respond earlier to less dosage of IVIG without statistical significance. All of the 2 chronic ITP cases with VV polymorphism did not respond to ordinary treatment like steroid or IVIG. Conclusion: The limitation of this study is the small sample size. Further study is needed with more patient in the future.