[Study of polymorphism of Fc gamma IIa receptors in Chilean patients with systemic lupus erythematosus].

Background: Polymorphisms of Fc receptors for IgG (Fc gamma R) have been proposed as a genetic factor that influences susceptibility for systemic lupus erythematosus (SLE). Human Fc gamma RIIa has 2 codominantly expressed alleles, H131 and R131, which differ at amino acid position 131 in the second extracellular domain (histidine or arginine respectively) and differ substantially in their ability to bind human IgG2. The H131 allele binds IgG2 efficiently, whereas R131 binds it poorly.