FcγRIIa polymorphism in human immunodeficiency virus-infected children with invasive pneumococcal disease

Invasive pneumococcal disease (IPD) occurs frequently in HIV-infected children and adults. Defects in complement function, opsonic capsular antibodies, and Fc receptor antibody-mediated phagocytosis could contribute to impaired host defense against Streptococcus pneumoniae. The objective of this study was to define the distribution of the three FcγRIIa genotypes in HIV⁺ children, including those with IPD. Forty-eight HIV⁺ Hispanic children, including eight with IPD, followed at Bronx Lebanon Hospital Center, Bronx, New York, nine HIV⁺ adults with IPD, and 56 HIV^- Hispanic control subjects were studied. The children and adults were identified retrospectively except for one child who developed IPD during the study. FcγRIIa genotypes were determined by PCR amplification of the FcγRIIa locus from genomic DNA samples and hybridization of the PCR products with allele- specific oligonucleotides. Naturally occurring serum antibodies reactive with four pneumococcal polysaccharide serotypes were determined by ELISA in seven of eight children with IPD. There were no statistical differences in FcγRIIa genotypes between HIV⁺ children with and without IPD, HIV⁺ adults with IPD, or HIV^- Hispanics. The predominant IgG subclass of pneumococcal polysaccharide binding antibodies in the seven HIV^- children with IPD studied was IgG₁. The distribution of FcγRIIa genotypes in HIV⁺ children with and without IPD is similar to that of the normal Hispanic population. The prospect of passive immunotherapy with specific anticapsular antibodies might be a promising alternative for the treatment and/or prevention of IPD in HIV^- children and other immunodeficient groups.