FCGR2A-131R Is Associated with Lupus Nephritis Rather than Non-Lupus Nephritis SLE in an Indigenous African Caribbean...

Fc gamma receptors (FcγRs) control humoral and cellular immune responses and maintain the immune system balance. Functional polymorphisms of FcγRs, whose prevalence was dependent on ethnic origin, were found to be associated with systemic lupus erythematosus (SLE) or kidney injuries in several ethnic groups. We aimed at investigating the association between the functional single-nucleotide polymorphisms (SNPs) of FcγRIIa-H131R (rs1801274), FcγRIIb-I232T (rs1050501), FcγRIIIa-V158F (rs396991) and FcγRIIIb variants (NA1 and NA2) and lupus erythematosus systemic in an indigenous African Caribbean population. We compared the frequencies of the functional SNPs of FCGR2A (FcγRIIa-H131R, rs1801274), FCGR2B (FcγRIIb-I232T, rs1050501), FCGR3A (FcγRIIIa-V158F, rs396991) and FCGR3B variants (FcγRIIIb NA1 and NA2) between lupus and healthy controls in an indigenous African Caribbean population. We highlighted an association between the FCGR3B-NA1/NA1 and FCGR3A-158F alleles and systemic lupus erythematosus, in addition to an association between FCGR2A-131R and lupus nephritis. Furthermore, an increase in the 131R-158V haplotype in lupus nephritis (30.4%) vs. lupus non-nephritis (15.8%) was noticed. Surprisingly, in spite of the high frequency of the FCGR2B-232T allele in our population, our study did not highlight any association of this allele either with SLE or lupus nephritis (a severe and frequent form of SLE). CD72-Hap1, which has been shown to confer resistance to SLE against T232 allele, was not enhanced in the control group. Our results emphasize an association between FCGR2A-131R and lupus nephritis with a distinctive FCGR polymorphism distribution in an indigenous African Caribbean population, confirming the important variation in the FCGR locus depending on ethnic origin.