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

Submit Manuscript | http://medcraveonline.com have been performed; however, these studies were small and generated differing conclusions [6-8]. Normal ranges for CBC are quite broad with the highest value at the top of the normal range often several fold higher than the lowest value at the bottom of the normal range [9]. Because normal ranges are so broad, it is also possible that leukocyte count may serve as a crude measure of more subtle differences in the immune system and represent determinants of HPV clearance in healthy individuals.


Introduction
Differential white blood cell (WBC) counts are routinely used as markers of overall health status as abnormal values can indicate infection, cancer, and other diseases [1][2][3][4][5]. More recently, WBC counts (highest versus lowest quartile) demonstrated a significant association with metabolic syndrome, hyper triglyceridemia, low HDL-cholesterol, and high fasting blood glucose [2]. Several smaller studies categorizing quantitative and qualitative T cell lymphocyte and other leukocyte measures in women with precancerous cervical lesions or cervical cancer

Study Population
We used data from the Costa Rica Human papillomavirus (HPV) 16/18 vaccine trial (CVT) in Guanacaste, Costa Rica which has been previously described [11]. In brief, CVT is a communitybased double-blind randomized controlled phase III trial of a virus-like particle (VLP) vaccine against HPV types 16 and 18. Women were invited to participate based on a census of the young adult female population in the region; the CVT included 7,466 healthy 18-25 year old women. The trial (NCT00128661, ClinicalTrials.gov) was reviewed and approved by the human subjects review committees of INCIENSA (Instituto Costarriciense de Investigacion y Ensenanza en Nutricion y Salud) in Costa Rica and the National Cancer Institute in the United States and all participants signed IRB-approved informed consent forms.
As part of the trial, women were interviewed to obtain information about risk factors related to HPV infection and cervical cancer and a detailed medical history and physical exam were performed by the study clinicians. After eligibility determination, and prior to vaccination, blood for complete blood count (CBC) analysis was collected and a pelvic exam was performed on sexually active participants. The processing of blood samples was performed by Trilab Sci, Liberia and CBC counts were obtained using the ABX Micros 60 hematology analyzer (ABX Diagnostics Montpellier, France). During the pelvic exam, exfoliated cells for cytology, HPV DNA and CT DNA were collected in PreservCyt solution. Processing of the PreservCyt vial for preparation of liquid-based, monolayer cytology slides, HPV and CT detection, and processing of the blood samples have been previously described [11]. Women with cytological evidence of high grade disease or cancer were referred to colposcopy where biopsies were performed for histological diagnosis of HPVassociated squamous intraepithelial lesions.
We defined HPV positivity as i.
'Any HPV-positive' if the participant was positive for at least one HPV type.

Analysis
This is a cross-sectional analysis of data and information collected at the study's enrollment visit (prior to vaccination). As sexual experience is a prerequisite for STI exposure only the 5711 non-virgins, representing approximately two thirds of all enrolled women were included in the current evaluation. We analyzed the association between peripheral lymphocyte, monocyte, granulocyte, and WBC counts and with HPV-positivity at the cervix, CT positivity at the cervix, and cytologically detected ASCUS, LSIL, or HSIL. Leukocyte markers evaluated were checked for distributional properties, and categorized into tertiles of low, medium and high values. Using polytomous logistic regression models, separate analyses were performed for each marker and outcome. All analyses were two-sided. Analyses were performed using SAS and were adjusted for age, body mass index (BMI), smoking, educational grade completed, hormonal contraception, number of sex partners, number of live births, years since first sex, marital status, and CT (for all models except for CT). Women with missing values for any of the CBC counts or those with missing information for adjustment factors were excluded from the analysis. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated and P-trend analysis was used to assess statistical significance.

Results
In our population of young, healthy, sexually experienced females (n=5711), 14% tested positive for CT, 42.1% tested positive for any type of HPV (non-carcinogenic and/or carcinogenic) and 35.4% tested positive for at least one type of carcinogenic HPV (Table 1). Overall, HPV-associated lesions were detected in 15.8% of women. Within this population a wide range of normal values for the immune cell parameters was observed ( Table 2).
No significant associations were found between any of the peripheral leukocyte counts measured and CT. We observed some significant associations between leukocyte counts, HPV and HPV-associated lesions. In separate models, we found that higher lymphocytes counts (3 rd tertile) were associated with a decreased odds of any type of HPV infection (data not shown) and separately also with decreased odds of any type of lesion (data not shown). Further analysis revealed that these associations were driven mainly by the decreased odds of carcinogenic HPV positive HSIL (OR Lymphocyte high vs. low tertile : 0.62; 95% CI (0.43, 0.88); P-trend=0.02) in women with higher lymphocyte counts (Table 3).

Discussion
Our results suggest that higher numbers of circulating lymphocytes are associated with decreased incidence of carcinogenic HPV positive HSIL. To our knowledge this study is the first to evaluate the association between peripheral differential leukocyte counts and CT, HPV infection, and HPVassociated disease in a large population of young, healthy, well-characterized women. This suggests that a higher number of circulating lymphocyte counts may be protective from carcinogenic HPV-positive HSIL.
Past studies have demonstrated that lymphocytes appear to be directly involved in clearance of carcinogenic HPV, regression of HPV-associated lesions, and lack of lymph node metastasis    Presently, aberrant leukocyte counts are used for the diagnosis of various disease states including malignancy and HIV [3,14]. Leukocyte counts are also used as prognostic markers of survival at the time of diagnosis and often, again, after administration of therapy [5]. Even though carcinogenic HPV infection and lesions are largely silent disease states, devoid of signs or symptoms of systemic infection, differences in circulating leukocyte counts and more specifically, in lymphocyte counts, may be determinants of disease progression and act as correlates of HPV immunity.

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
We did not find any associations between leukocyte counts and the presence of CT infection. CT and HPV both require cellmediated immunity for pathogen clearance, though systemic leukocyte counts were not associated with the presence of CT infection. This observation could indicate that the respective bacterial and viral pathogens have different determinants of infection or indicate that our HPV-associated findings are spurious. Our study has additional limitations. This study only includes rudimentary categories of leukocytes, which lack phenotypic or functional resolution. Lastly, this study was crosssectional in design; a future longitudinal study would allow adjustment for changes within an individual's leukocyte counts over time.

Conclusion
Differential CBC counts as an indicator of disease risk warrants replication and further exploration of lymphocyte subsets in HPV infection and cervical disease. Comparison of the localized and systemic immune response to infection is likely to be fruitful [15], as analyses of the infiltrate of leukocytes and other immune cells at the cervix during the progression of persistent carcinogenic HPV infection may better identify characteristics of protective and permissive immune responses in HPV-associated cervical disease.