FC-GAMMA RECEPTOR IIA H R131 POLYMORPHISM IN PATIENTS WITH ANTIPHOSPHOLIPID ANTIBODIES/

A role for Fc gamma receptor in the pathophysiology of thrombosis in A PS has been hypothesized. The polymorphism of this receptor, Fc gamma RIIA H/R131, is associated with the binding affinity for human IgG(2) (i.e. Fc gamma RIIA-H131 isoform has a higher affinity than Fc gamma R IIA-R131). Since anti-beta(2) glycoprotein I antibodies (anti beta(2)G PI), which play a major pathogenic role in APS, show IgG(2) dominant d istribution, we investigated the prevalence of receptor isoforms in pa tients with antiphospholipid antibodies (aPL) by a PCR-RFLP method. We studied 100 Caucasian patients with aPL. (57 primary APS, 32 secondar y APS to SLE and II other diseases with aPL) and 41 healthy controls. H131/H131, H131/R131 and R131/R131 genotypes were found in 21 (21%), 5 0 (50%) and 19 (29%) in the patient group, and 9 (22%). 23 (56%) and 9 (22%) in control group, respectively. Thus there was no statistically significant difference in the prevalence of each genotype in these gr oups. None of the clinical manifestations of primary APS (arterial/ven ous thrombosis, recurrent pregnancy loss and thrombocytopenia) was sig nificantly correlated with any Fc gamma RIIA genotype. In conclusion, Fc gamma RIIA polymorphism did not correlate with the manifestations o f APS, and Fc gamma IIA genotype is not a genetic marker of APS.