Occurrence of IgA and IgG antibodies to select peptides representing human papillomavirus type 16 among cervical cancer cases and controls.

We used an enzyme-linked immunosorbent assay to test sera from 186 cases of invasive cervical cancer and 172 age-matched controls for IgG and IgA antibodies to an human papillomavirus 16 E7 peptide and to peptide 245, representing an epitope in E2. Cases had significantly higher mean absorbance values than controls for both immunoglobulin isotypes to E7 and elevated mean values for IgG to peptide 245. Since absorbances were not normally distributed we analyzed cervical cancer risk for seropositive and seronegative women. Of the traditional cervical cancer risk factors, cigarette smoking, educational level, number of pregnancies, time interval since last Papanicolaou smear, and age at first intercourse influenced the distribution of seropositivity to some of the viral antigens. Adjusting for these variables, the odds ratios of cervical cancer associated with IgG to E7 was 5.28 [95% confidence (95% CI) = 2.4-11.6] and that with IgA to E7 was 2.67 (95% CI = 1.3-5.3). IgG to peptide 245 was less strongly associated, odds ratio 1.68 (95% CI = 1.2-3.3), and IgA to peptide 245 was not significantly associated with disease. These findings suggest that antibodies to E7 are markers for invasive cervical cancer. However, seropositivity correlated poorly with clinical state, survival, or the presence of human papillomavirus DNA in the cancer tissue.