A possible association between FCGR polymorphisms and severity of malaria in Thai

Abstract

Human Fcγ receptor (FCGR) genes form a clustered gene family on chromosome 1q23, that consists of FCGRIA, IIB, IIC, IIIA, and IIIB genes. We previously reported that the FCGRIIA-131H/H genotype in combination with the FCGRIIIB-NA2 allele is associated with susceptibility to cerebral malaria, while such an association can be caused by linkage disequilibrium (LD) between these polymorphisms and the primary associated gene (s) in this region. FCGRIIIA is known to exhibit genetic polymorphism, FCGRIIIA- 176F/V, coding for different affinity to IgG1 and IgG3. In this study, we examined a possible association of FCGRIIIA-176F/V polymorphism with the severity of malaria in 462 adult Thai patients with Plasmodium falciparum malaria. The frequencies of the FCGRIIIA-176V among patients with mild malaria, with non-cerebral severe malaria, and with cerebral malaria were 32.7%, 29.9%, and 36.6%, respectively. This polymorphism showed neither positive nor negative association with the severity of malaria. Thus, we conclude that the association of FCGRIIA-131H/R and FcgRIIIB-NA1/NA2 polymorphisms with cerebral malaria in Thailand is not due to the LD with FCGRIIIA-176F/V.