Fcγ Receptor IIa Polymorphism in Egyptian Patients with Systemic Lupus Erythematosus

Background: Systemic Lupus Erythematosus (SLE) is a complex, multifactorial auto-immune disease. Receptors for IgG play an important role in immune complex clearance. Several studies have identified polymorphisms of receptors for the Fc fragment of IgG (FcγR) as genetic factors influencing the susceptibility and course of such a disease. It has been also suggested that FcγRIIa polymorphism may be an important risk factor for development of lupus nephritis.Objective: This study was done to examine the frequency of FcγRIIa R/H131 polymorphism among Egyptian patients with SLE, as well as, to determine whether FcγRIIa polymorphism, represents a risk factor for both SLE susceptibility and lupus nephritis.Patients and Methods: Forty four Egyptian patients were diagnosed with SLE according to the American College of Rheumatology Criteria. Both SLE patients and healthy controls were genotyped for FcγRIIa R/H131 polymorphism using a single step allele PCR based method.Results: No statistically significant difference was found in the frequency of FcγRIIa genotypes (H/H, H/R and R/R) between SLE patients and normal controls (p 0.05). However, a small excess of R/R allele was seen in the SLE patients but this did not reach statistical significance (total SLE versus controls: OR 1.6, 95% CI 0.69-3.7, p 0.05). Moreover, a possible susceptibility to lupus nephritis which may be related to FcγRIIa R/R allele was suggested in the Egyptian patients, but this also did not reach statistical significance (OR 1.6, 95% CI0.47-5.3, p 0.05). No statistically significant relation was found between FcγRIIa genotypes and age, age at onset and duration of the disease (p 0.05). Also, no statistically significant association between clinical manifestations and FcγRIIa polymorphism was demonstrated in this study. Serological assessments demonstrated that FcγRIIa H/H 131 allele was significantly associated with double-stranded DNA antibody (OR 1, 95% CI0.27-3.3, p 0.05), while no statistically significant association was demonstrated with anti-Smith antibody (p 0.05).Conclusion: FcγRIIa polymorphism may possibly constitute a minor determinant that could influence the susceptibility to SLE and lupus nephritis. However, it seems that it does not represent a well recognized genetic risk factor neither for SLE susceptibility nor for the development of lupus nephritis in Egyptian SLE patients.