Fcă receptor Iia (Cd32) heterogeneity in patients with recurrent bacterial respiratory tract infections

LAM Sanders, JGJ van de Winkel… - Journal of Infectious …, 1994 - academic.oup.com
LAM Sanders, JGJ van de Winkel, GT Rijkers, MM Voorhorst-Ogink, M de Haas, PJA Capel…
Journal of Infectious Diseases, 1994academic.oup.com
Abstract Fc-ăRIIa (CD32) is the sole IgG Fc receptor capable ofinteraction with human IgG2,
the main IgG subclass of bacterial capsular polysaccharides. The two genetically
determined allotypes of human Fc-ăRIIa, Fc-ăRIIa-R131 and IIa-H 131 alleles, have
functionally different reactivities with human IgG2. The capacity of polymorphonuclear
leukocytes (PMNL) homozygous for Fc-ăRIIa-H/HI31 for IgG2 opsonized bacteria is
significantly higher than phagocytosis by PMNL homozygous for Fc-ăRIIa-R/R131 …
Abstract
Fc-ăRIIa (CD32) is the sole IgG Fc receptor capable ofinteraction with human IgG2, the main IgG subclass of bacterial capsular polysaccharides. The two genetically determined allotypes of human Fc-ăRIIa , Fc-ăRIIa-R131 and IIa-H 131 alleles, have functionally different reactivities with human IgG2. The capacity of polymorphonuclear leukocytes (PMNL) homozygous for Fc-ăRIIa-H/HI31 for IgG2 opsonized bacteria is significantly higher than phagocytosis by PMNL homozygous for Fc-ăRIIa-R/R131, independent of the Fc-ăRIIIb-NA1/NA2 (CDI6) allelic polymorphism. To test the clinical significance of these FcăR polymorphisms, Fc-ăRIIa and Fc-ăRIIIb phenotypes of 48 children with recurrent bacterial respiratory tract infections were determined. Fc-ăRIIa-H/HI31 was less than half that observed in 123 healthy adults (P = .01). IgG2 responses were low in 25 of 48 patients after immunization with pneumococcal vaccine. These results suggest that Fc-ăRIIa polymorphism may contribute to increased susceptibility to infections with encapsulated bacteria in a childhood population with low IgG2 anti-carbohydrate antibodies.
Oxford University Press