Fca Receptor Iia (Cd32) Polymorphism In Fulminant Meningococcal Septic

Abstract

Antibodies are essential in host defense against Neisseria meningltidis. Therefore, interactions among IgG and Fe receptors (FcãR) on phagocytes may be crucial. Genetic polymorphic forms of FcãRIIa (CD32) express different functional activities. In a retrospective study, FcãR polymorphisms were determined in 25 children who survived fulminant meningococcal septic shock: 11 had FcãRIIa-R/RI31, the poor IgG2-binding allotype, which is a significantly more frequent rate than found in a healthy white population (44% vs. 23%; P = .028; odds ratio = 2.67; 95% confidence interval, 1.09–6.53). The relevance of this finding was further supported by the fact that neutrophils with the FcãRIIa-RjRI31 allotype phagocytized N. meningitidis opsonized with polyclonal IgG2 antibodies less effectively than did IIa-H/HI31 neutrophils. Our findings suggest an important role for anti-No meningitidis IgG2 and the FcãRIIa polymorphism in host defense against systemic meningococcal infections.