Fc gamma RIIa, IIIa and IIIb polymorphisms in Turkish children susceptible to recurrent infectious diseases

Abstract

The efficacy of IgG-induced Fc gamma receptor (FcγR) function displays interindividual heterogeneity due to genetic polymorphisms of three FcγR subclasses: FcγRIIa, FcγRIIIa and FcγRIIIb. FcγR polymorphisms may contribute to disease susceptibility or may alter disease course. The aim of this study is to examine FcγR gene polymorphisms in Turkish children with recurrent respiratory tract infections and without well known humoral immunodeficiencies. For the patients in the study group (n=52), recurrent infection was defined as the presence of at least six infection episodes a year. Seventy-one healthy children with a maximum of two infections in a year were enrolled as the control group. Subjects in both groups had no abnormalities in serum immunoglobulins, IgG subsets and specific antibody levels. For FcγRIIa: H131H, H131R, R131R genotypes and 131R, 131H alleles; for FcγRIIIa: F158F, F158V, V158V genotypes and 158F, 158V alleles; and for FcγRIIIb: –NA1/NA1, NA1/NA2, NA2/NA2 genotypes and NA1, NA2 alleles were determined by using amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Compared with the control group, the FcγRIIa-R131R genotype and 131R allele were found to be significantly elevated in the study group, and FcγRIIa-H131H genotype and 131H allele in the study group were significantly lower than in the control group. Genotypes and alleles related with FcγRIIIa and FcγRIIIb gene polymorphisms did not show any significant difference between the study and control groups. FcγRIIa gene polymorphism (R131R) may increase the risk and susceptibility for recurrent infectious diseases in children.