Type specificity and significance of different isotypes of serum antibodies to human papillomavirus capsids

Isotype-specific serum antibody responses against human papillomavirus (HPV ) type 16 were evaluated by use of cross-sectional, prospective, and popula tion-based seroepidemiologic studies. IgG1 and IgA were the most abundant i sotypes. No sample contained IgG2, and <25 samples contained IgG3 or IgM. T otal IgG, IgA, and IgG1 were HPV type specific and were associated with HPV -16 DNA (odds ratios [ORs], 5.4, 5.0, and 5.9, respectively; P<.001)but not with other HPV DNA (ORs, 1.2, 1.2, and 0.8, respectively; P value was not significant). Total IgG and IgG1 were strongly associated with number of li fetime sex partners (P <.001); IgA was only associated with number of recen t sex partners and lifetime sex partners among younger women. Total IgG, Ig G1, and IgA were associated with cervical intraepithelial neoplasia type II I and also predicted risk of future cervical neoplasia. Ige and IgG1 appear ed to mark lifetime cumulative exposure, whereas IgA may mark recent or ong oing infection.