FC-GAMMA RECEPTOR IIA (CD32) POLYMORPHISM IN FULMINANT MENINGOCOCCAL SEPTIC SHOCK IN CHILDREN

Antibodies are essential in host defense against Neisseria meningitidi s. Therefore, interactions among IgG and Fc receptors (Fc gamma R) on phagocytes may be crucial. Genetic polymorphic forms of Fc gamma RIIa (CD32) express different functional activities. In a retrospective stu dy, Fc gamma R polymorphisms were determined in 25 children who surviv ed fulminant meningococcal septic shock: 11 had Fc gamma RIIa-R/R131, 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 wi th the Fc gamma RIIa-R/R131 allotype phagocytized N. meningitidis opso nized with polyclonal IgG2 antibodies less effectively than did IIa-H/ H131 neutrophils. Our findings suggest an important role for anti-N. m eningitidis IgG2 and the Fc gamma RIIa polymorphism in host defense ag ainst systemic meningococcal infections.