The Fc gamma RIIIA-158F allele is a risk factor for systemic lupus erythematosus

Objective. To study whether the Fc gamma RIIIA-158V/F polymorphism, which affects IgG binding affinity, is a risk factor for systemic lupus erythematosus (SLE),

Methods. We genotyped a group of 70 Caucasian SLE patients for all known Fc gamma R polymorphisms. Of this group, 45 patients (64%) had nephritis, In 35 patients, this diagnosis was confirmed by renal biopsy,

Results, In the total group of 70 SLE patients, the frequency of the Fc gamma RIIIA-158F allele was 0.74, versus 0.57 in healthy controls (P = 0.003), The genotype distribution of the Fc gamma RIIIA-158V/F polymorphism was also significantly different from that of the control population (P = 0.004). The distribution of the other Fc gamma R polymorphisms-Fc gamma RIIA-131R/H, Fc gamma RIIIB-NA(1/2), and Fc gamma RIIIA-48L/R/H-was similar in SLE patients and controls,

Conclusion. In our group of SLE patients, only the distribution of the alleles of the Fc gamma RIII4-158V/F polymorphism nas significantly different from that in the control group. This might indicate that macrophage expression of the Fc gamma RIIIA-158F isoform is involved in the disturbed clearance of immune complexes in patients with SLE.