ABNORMAL DISTRIBUTION OF FC-GAMMA RECEPTOR-TYPE IIA POLYMORPHISMS IN KOREAN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. Abnormal immune complex clearance is a feature of systemic lupus erythematosus (SLE), Polymorphisms of the Fc gamma receptor type IIa (Fc gamma RIIa) genes (the receptor binds IgG2 and IgG3) are impo rtant disease susceptibility factors in some populations. This study s ought to determine the effects of these polymorphisms among Korean pat ients with SLE. Methods. Polymerase chain reaction of genomic DNA and allele-specific oligonucleotide hybridization were used to determine F c gamma RIIa genotypes in Korean patients with SLE and healthy control subjects, Clinical manifestations were analyzed in each patient and c orrelated with the genotypes. Results. Among the 73 SLE patients, ther e was an abnormal distribution of Fc gamma RIIa alleles when compared with 64 controls: 11.0% of the SLE patients were homozygous for Fc gam ma RIIa-H131 compared with 34.4% of the controls (odds ratio [OR] 0.20 , 95% confidence interval [95% CI] 0.04-0.95, chi(2) = 5.7, P = 0.0169 9), The allelic frequency of Fc gamma RIIa-H131 was significantly lowe r in the SLE patients than in the controls (49.3% versus 63.3%; P = 0. 02019), and it was also significantly lower in lupus patients with nep hritis compared with the normal population (OR 0.53, 95% CI 0.29-0.95, chi(2) = 5.15, P = 0.02330), but was not significantly lower in lupus patients without nephritis (P = 0.13663 versus controls), Clinically, the level of proteinuria was significantly higher in the lupus nephri tis patients who bad R/R131 than in those who had H/H131 or R/H131. Co nclusion. An abnormal distribution of Fc gamma RIIa polymorphisms was associated with SLE in Korean patients, There was a significant decrea se in the Fc gamma RIIa-H/H131 genotype and H131 allelic frequency in SLE patients, particularly in those with nephritis, This suggests that the H131 allele confers some protection from SLE in this population.