GEOGRAPHIC-VARIATION IN THE HUMORAL RESPONSE TO PNEUMOCYSTIS-CARINII

The reported incidence of Pneumocystis carinii pneumonia varies in dif ferent areas of the world, but little is known about geographic variat ion in the antibody response to specific antigens. The frequency of an ti-P. carinii antibodies in the serum of normal and human immunodefici ency virus (HIV)-infected individuals from five different regions was compared. Serum specimens from 948 subjects were assayed for IgG antib odies to human-derived P. carinii by Western blot. The overall prevale nce of anti-P. carinii antibodies was 72.9%. Among HIV-seronegative in dividuals, the rate of seropositivity was similar in all regions (70.5 %-82.4%). Antibodies to the 30- to 40-kDa antigen were most commonly d etected. The frequency of antibodies to high-molecular-mass antigens ( 95, 120, and > 120 kDa) demonstrated significant geographic variation. This study demonstrates that antibody responses to P. carinii are com mon in all areas studied but vary in frequency and pattern.