Antibodies against pneumococcal polysaccharides after vaccination in HIV-infected individuals: 5-year follow-up of antibody concentrations

We studied the production of IgG antibodies against eight pneumococcal poly saccharide serotypes (PPS) 1, 4, 6B, 9V, 14, 18C, 19F and 23F after vaccina tion of 50 HIV-infected adults with 23-valent Pneumovaxa(R)23 and the cours e of the antibodies against four PPS during the following years. Mean antib ody concentrations against PPS 18C, 19F and 23F were sigificantly lower in the patients with CD4(+)-lymphocyte counts <200 x 10(6)/l than in healthy c ontrols; mean antibody concentrations against PPS 1, 4, 9V, 6B and 14 were similar in HIV-infected individuals and controls. Although it has been assu med that polysaccharides induce a T-cell-independent immune response, our r esults indicate that some PPS are T-cell-independent type 2 antigens. The r ates of decline of mean antibody concentrations in HIV-infected individuals and in healthy controls were similar during 5 y after vaccination. However , as a consequence of the low postvaccination antibody concentrations again st several PPS, within 3 y after vaccination most HIV-infected individuals had antibody concentrations below the level which is assumed to be required for protection. (C) 1999 Elsevier Science Ltd. All rights reserved.