Peripheral Leukocyte Counts and Risk of Chlamydia Trachomatis (Ct), Human Papilloma viruses (HPV) and Cervical Disease: A Cross-Sectional Study in a Cohort of Young Women

Abstract

Background: Differential white blood cell (WBC) counts are routinely used as a marker of overall health status as abnormal values can indicate infection, cancer, and other diseases. Recently, differences in WBC within normal ranges have been associated with health outcomes. The human Papilloma virus (HPV) 16/18 vaccine trial in Guanacaste, Costa Rica enrolled 5,711 sexually active healthy women between the ages of 18 and 25 at which time all participants had blood collected for a complete blood count (CBC) as part of a routine clinical assessment. Methods: Using polytomous regression we investigated the associations between circulating leukocyte measures within CBC (granulocytes, lymphocytes, monocytes, total WBC) and chlamydia trachomatis (CT), HPV and HPV-associated low or high squamous intraepithelial lesions (LSIL or HSIL) present at the time of blood collection. Odds ratios (OR) and 95% confidence intervals (95% CI) are presented. Results: Higher lymphocyte counts were associated with a decreased risk of HSIL in women with carcinogenic HPV infection (ORLymphocyte high vs. low tertile: 0.62; 95% CI (0.43, 0.88); P-trend=0.02). No significant associations were observed between leukocyte counts and CT status. Conclusion:The associations we observed between high lymphocyte counts and a decreased prevalence of carcinogenic HPV positive HSIL were significant. Additional studies investigating the role of lymphocyte counts as an indirect risk factor for HPV persistence are needed. In the future, large studies linking peripheral and local leukocyte counts to phenotype and function may identify subsets which are protective from carcinogenic HPV positive HSIL.