Serum IgG antibodies to HPV6 L1, E2, E4, E6, and E7 proteins among children prospectively followed-up for three years.

BACKGROUND: Current knowledge implicates that human papillomavirus (HPV) infection can be acquired at early age. However, the role of HPV-specific passive immunization from mother to neonate is nearly unexplored, especially against the HPV early proteins. We analyzed IgG antibodies against HPV6 early (E2, E4, E6, E7) and late (L1) proteins in children prospectively followed-up for three years. METHODS: A total of 272 children and their mothers from the Finnish Family HPV Study were included in these analyses. Serum samples were obtained from pregnant mothers at their third trimester and from newborn/infants at 1-, 2-, 6-, 12-, 24-, and 36-month visits after birth. Antibodies to the early and late proteins were analyzed by multiplex serology based on glutathione S-transferase fusion protein capture to fluorescent beads. RESULTS: Maternal antibodies to all tested HPV6 proteins were transferred to neonates, concordance between maternal and neonates' antibody levels being highly significant (p<0.001). Seropositivity of HPV6 L1 in the neonates declined during the first six months of life, whereas changes in the E-protein antibodies were less obvious. After the maternal antibodies have vanished, seroconversion to HPV6 L1 at 12 months (median) and to the HPV6 E-proteins between 23-35 months was observed. CONCLUSION: IgG antibodies against HPV6 E- and L-proteins are transferred from mothers to their children. Seroconversion against HPV6 L1, E2, E4, E6, and E7 does occur in early childhood, as a sign of acquired HPV6 infection by vertical or horizontal transmission starting at 12 months of age.

Impact of Different Cofactors on Naturally Acquired Human Papillomavirus Antibody Levels Among Unvaccinated Pregnant Women.

Human papillomavirus (HPV) infections are common, transmitted by sexual and nonsexual routes. The present case-control setting was designed to examine potential cofactors associated with either persistently low or high HPV-antibody levels. The study subjects were from the Finnish HPV Family cohort of 329 baseline pregnant, non-HPV-vaccinated women, who were sampled for genital and oral HPV-DNA and HPV serology at baseline, and at 12, 24, and 36 months. Antibodies to the L1 major capsid protein of HPV 6, 11, 16, 18, and 45 were analyzed by multiplex HPV serology and HPV genotyping was performed. This study included 59 women, 23 women with persistently low (<200 median fluorescence intensity [MFI]) and 36 women with persistently high and always positive (>200 MFI) levels of these antibodies for all five HPV genotypes. Potential HPV-associated covariates were derived from detailed questionnaires. Only cofactors other than detected HPV genotype significantly impact on the levels of natural HPV antibodies. A higher number of past sexual partners or a history of diagnosed genital warts were significant covariates of high HPV antibody levels (p = 0.023 and p = 0.043, respectively). Of interest, women with a history of allergies presented with low levels of HPV antibodies (p = 0.03), potentially exposing these women to an increased risk of future HPV-related diseases that merit closer surveillance.

Effect of a Second Pregnancy on the HPV Serology in Mothers Followed Up in the Finnish Family HPV Study.

The impact of pregnancy on human papillomavirus (HPV) natural antibody levels is not fully understood. We tested the seroprevalence and levels of HPV 6, 11, 16, 18 and 45 antibodies at different time points among 89 women with a second pregnancy and 238 nonpregnant women during their 36-month followup. All participants were unvaccinated for HPV and pregnant at the enrollment of the study. Serum samples were collected from the mothers at baseline and at the 12-month, 24-month, and 36-month followup visits. No statistically significant differences in mean antibody levels were observed in women who developed a second pregnancy compared to their nonpregnant counterparts. Between these two groups, statistically significant differences in serostatus were observed, particularly if the second pregnancy was ongoing at the 24-month timepoint. Accordingly, women with a second pregnancy were more likely to be seronegative for HPV 6, 11, 18, and 45 as compared to the nonpregnant women, the reverse being true for HPV16. In contrast, the women with an ongoing second pregnancy showed a higher prevalence of HPV16 seropositivity at the 36-month followup. These data suggest that a second pregnancy does not seem to have a major impact on the levels of HPV antibodies, but it might influence the serological outcomes.

Peripheral Blood T-lymphocyte Phenotypes in Mother-Child Pairs Stratified by the Maternal HPV Status: Persistent HPV16 vs. HPV-Negative: A Case-Control Study.

Only few studies exist on the phenotype distribution of peripheral blood lymphocytes concerning persistent oral HPV infection. T-lymphocyte subsets were phenotyped in women who had persistent genital or oral HPV16 infection, using HPV-negative women as a reference group. A subset of 42 mothers and their children (n = 28), were stratified into two groups according to the mothers' HPV status. PBMCs from previously cryopreserved venous samples were immunophenotyped by flow cytometry. Proportions of the CD4+ or CD8+ lymphocytes by their immunophenotype subsets were compared between HPV-positive and -negative mothers and their children. The mean rank distribution of CD8+ memory cells was significantly higher among mothers with persistent genital HPV16 infection. The median levels of both the antigen-presenting CD4+ cells and activated CD8+ cells were significantly lower in mothers with persistent oral HPV16 infection. When oral and genital HPV16-persistors were analyzed as a group, a marker of terminal effector cells was significantly increased as compared to HPV-negative women. Significantly higher levels of activated CD4+, CD8+ and circulating CD8+ memory cells were found among children whose mothers had persistent oral HPV16 infection. Persistent HPV16 infections are associated with changes in peripheral blood T-lymphocyte subsets. The mother's persistent oral HPV16 infection possibly results in immune alterations in her offspring.