Humoral, Mucosal, and Cell-Mediated Immunity Against Vaccine and Nonvaccine Genotypes After Administration of Quadrivalent Human Papillomavirus Vaccine to HIV-Infected Children

OBJECTIVES: To characterize the immunogenicity of a quadrivalent human papillomavirus vaccine (QHPV) in human immunodeficiency virus (HIV)-infected children, we studied their immune responses to 3 or 4 doses. METHODS: HIV-infected children aged 7-12 years with a CD4 cell percentage of ≥15% of lymphocytes, received 3 doses of QHPV with or without a fourth dose after 72 weeks. Type-specific and cross-reactive antibodies and cell-mediated immunity were measured. RESULTS: Type-specific antibodies to HPV6, 11, and 16 were detected in 100% and ≥94% of children at 4 and 72 weeks, respectively, after the third QHPV dose. Corresponding numbers for HPV18 were 97% and 76%, respectively. A fourth QHPV dose increased seropositivity to ≥96% for all vaccine genotypes. Four weeks after the third QHPV dose, 67% of vaccinees seroconverted to HPV31, an HPV16-related genotype not in the vaccine; 69% and 39% of vaccinees developed mucosal HPV16 and 18 immunoglobulin G antibodies, respectively; and 60% and 52% of vaccinees developed cytotoxic T lymphocytes (CTLs) for HPV16 and 31, respectively. CONCLUSIONS: Three QHPV doses generated robust and persistent antibodies to HPV6, 11, and 16 but comparatively weaker responses to HPV18. A fourth dose increased antibodies against all vaccine genotypes in an anamnestic fashion. CTLs and mucosal antibodies against vaccine genotypes, as well as cross-reactive antibodies and CTL against nonvaccine genotypes, were detected.