Influence of FcyRIIa Polymorphism in Infectious or Autoimmune Disease

A few early studies have examined whether expression of the FcyRIIa-Arg/His131 polymorphism influences susceptibility to infectious or autoimmune disease. In theory, the weaker binding of human IgG2 to the FcyRIIa-Arg131 variant suggests that this gene might be overrepresented among patients with recurrent infections characterized by certain microbes with polysaccharide coats (i.e., involving an IgG2 antibody response) and overrepresented in disease characterized by circulating immune complexes (because phagocytic cells bearing the FcgRIIa-His131 variant would clear these complexes more readily). Certainly, a skewed genotypic distribution favoring the FcyRIIa-Arg131 variant has been noted in patients with Haemophilus influenzae infections (Sanders et al., 1994) and meningococcal septic shock (Bredius et al., 1994b). Furthermore, there is also predominance of FcgRIIa-Arg131 in patients with elevated levels of immune complexes and glo-merulonephritis complicating systemic lupus erythematosus (Duits et al., 1995) (Table 2).

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