Astrid Milena Bedoya

Increased CD4+/CD8+ Double-Positive T Cells in Chronic Chagasic Patients

Background CD4+/CD8+ double positive (DP) T cells have been described in healthy individuals as well as in patients with autoimmune and chronic infectious diseases. In chronic viral infections, this cell subset has effector memory phenotype and displays antigen specificity. No previous studies of double positive T cells in parasite infections have been carried out. Methodology/Principal Findings Seventeen chronic chagasic patients (7 asymptomatic and 10 symptomatic) and 24 non-infected donors, including 12 healthy and 12 with non-chagasic cardiomyopathy donors were analyzed. Peripheral blood was stained for CD3, CD4, CD8, HLA-DR and CD38, and lymphocytes for intracellular perforin. Antigen specificity was assessed using HLA*A2 tetramers loaded with T. cruzi K1 or influenza virus epitopes. Surface expression of CD107 and intracellular IFN-γ production were determined in K1-specific DP T cells from 11 chagasic donors. Heart tissue from a chronic chagasic patient was stained for both CD8 and CD4 by immunochemistry. Chagasic patients showed higher frequencies of DP T cells (2.1%±0.9) compared with healthy (1.1%±0.5) and non-chagasic cardiomyopathy (1.2%±0.4) donors. DP T cells from Chagasic patients also expressed more HLA-DR, CD38 and perforin and had higher frequencies of T. cruzi K1-specific cells. IFN-γ production in K1-specific cells was higher in asymptomatic patients after polyclonal stimulation, while these cells tended to degranulate more in symptomatic donors. Immunochemistry revealed that double positive T cells infiltrate the cardiac tissue of a chagasic donor. Conclusions Chagasic patients have higher percentages of circulating double positive T cells expressing activation markers, potential effector molecules and greater class I antigenic specificity against T. cruzi. Although K1 tetramer positive DP T cell produced little IFN-γ, they displayed degranulation activity that was increased in symptomatic patients. Moreover, K1-specific DP T cells can migrate to the heart tissue.

Unexpected inverse correlation between Native American ancestry and Asian American variants of HPV16 in admixed Colombian cervical cancer cases

BACKGROUND European (E) variants of HPV 16 are evenly distributed among world regions, meanwhile Non-European variants such as European-Asian (EAs), Asian American (AA) and African (Af) are mostly confined to Eastern Asia, The Americas and African regions respectively. Several studies have shown that genetic variation of HPV 16 is associated with the risk of cervical cancer, which also seems to be dependent on the population. This relationship between ethnicity and variants have led to the suggestion that there is co-evolution of variants with humankind. Our aim was to evaluate the relationship between the individual ancestry proportion and infection with HPV 16 variants in cervical cancer. METHODS We examined the association between ancestry and HPV 16 variants in samples of 82 cervical cancer cases from different regions of Colombia. Individual ancestry proportions (European, African and Native American) were estimated by genotyping 106 ancestry informative markers. Variants were identified by PCR amplification of the E6 gene, followed by reverse line blot hybridization (RLB) with variants specific probes. RESULTS Overall European (E) and Asian American (AA) variants frequency was 66.5% and 33.5% respectively. Similar distribution was observed in cases with higher proportions of European or African ancestry. A higher Native American ancestry was significantly associated with higher frequency of E variants (median ancestry>23.6%, Age and place of birth adjusted OR: 3.55, 95% CI: 1.26-10.03, p=0.01). Even further, an inverse geographic correlation between Native American ancestry and frequency of infections with AA variants was observed (ρ=-0.825, p=0.008). Regions with higher proportion of Native American ancestry had a lower frequency of AA variants of HPV 16. CONCLUSIONS This study suggests replacement of AA variants by E variants of human papillomavirus 16 in cervical cancer cases with high Native American ancestry.

Location and Density of Immune Cells in Precursor Lesions and Cervical Cancer.

Only a small proportion of women infected with Human Papillomavirus (HPV) develop cervical cancer. Host immune response seems to play a role eliminating the viral infection and preventing progression to cancer. Characterization of tumor infiltrating lymphocytes (TILs) in cervical pre-neoplastic lesions and cervical cancer may be helpful to understand the mechanisms that mediate this protection. The aim of this study was to determine if there are differences in the localization and density (cells/mm2) of CD8+ T-cells, CD4+ T-cells and Tregs (CD25 + Foxp3+) in cervical pre-neoplastic lesions and cervical cancer. Immunohistochemical analysis of sections of 96 (26 CIN1, 21 CIN2, 25 CIN3, and 24 SCC) samples revealed that regardless of CIN grades, CD8+ T-cells are more abundant than CD4+, CD25+ and Foxp3+ cells in both the stroma and epithelium. There was a higher density of CD8+ cells in the stroma of cervical cancer compared to CIN3 (OR = 4.20, 95% CI 1.2-15), CIN2 (OR = 7.86, 95% CI 1.7-36.4) and CIN1 (OR = 4.25, 95% CI 1.1-17). Studies evaluating whether these cells are recruited before or after cancer progression will be helpful to understand the role of these cells in the natural history of HPV-induced lesions.

Age-specific seroprevalence of human papillomavirus 16, 18, 31, and 58 in women of a rural town of Colombia.

Objective The study’s objective was to estimate human papillomavirus (HPV) genotype–specific seroprevalence to determine population HPV exposure and inform vaccine policy. Methods This study is a cross-sectional prevalence survey of 878 women of Pueblorrico, a rural town of Colombia. A standardized questionnaire was used to obtain information on demographic characteristics, sexual and reproductive history, and smoking habits. Seropositivity to HPV-16, -18, -31, and -58 was determined by virus-like particles in an enzyme-linked immunosorbent assay. Results Overall seropositivity to any HPV genotype was 27.9%. The combined seroprevalence of women 15 to 19 and 20 to 24 years old was 35.4% (95% confidence interval [CI], 25.9–46.2) and 36.0% (95% CI, 27.7–45.3), respectively. Seroprevalence for HPV-16 was 17% (95% CI, 14.6–19.6); for HPV-18, 9.8% (95% CI, 8.0–11.9); for HPV-31, 11.4% (95% CI, 9.5–13.7); and for HPV 58, 12.5% (95% CI, 10.5–14.9). Higher HPV seropositivity was associated with the lifetime number of occasional sexual partners (odds ratio, 3.05; 95% CI, 1.26–7.37) and having more than 2 regular sexual partners (odds ratio, 3.00; 95% CI, 1.21–7.45) in women younger than 44 and older than 45 years old, respectively. Use of oral contraceptives and tobacco/cigarettes was significantly associated with reduced HPV seropositivity in women older than 45 but not in women younger than 44 years old. Conclusions Human papillomavirus seropositivity is associated with measures of sexual behavior, particularly a greater lifetime number of sexual partners. Hormonal and tobacco/cigarette use may be factors influencing the HPV seropositivity in women older than 45 years old.

Prevalence of specific herpes simplex virus-2 antibodies and associated factors in women of a rural town of Colombia

There is lack of age-specific seroprevalence surveys and identification of factors associated with herpes simplex virus type-2 seropositivity (HSV-2) in rural populations in Colombia. A random sample of 869 women was interviewed about socio-demographic aspects, sexual and reproductive history. Antibodies to HSV-2 were determined by a specific type immunoenzymatic technique (ELISA). Participants had a mean age of 38±16.1 years, 67% were married, 60% monogamous and 47% reported use of condoms. HSV-2 seroprevalence was 19.1% (95% CI: 16.6-21.9) and it was strongly associated with increasing age (Ptrend<0.001). In the logistic regression analysis, women who reported between two or three lifetime sexual partners (OR=2.4; 95% CI: 1.5-3.7), >31 years of sexual activity with regular or occasional sexual partners (OR=4.3; 95% CI: 1.2-15.7) and not using condoms with regular sexual partners (OR=2.1; 95% CI: 1.4-3.3) were more likely to be HSV-2 seropositive. The overall seroprevalence rate of women of Pueblorrico, Colombia, is lower than that reported in other Latin American countries especially in women>45 years. The difference may be explained by higher prevalence of condom use in this population or lower exposure to herpes infection in male as well as females in the past.

Immunosuppression in cervical cancer with special reference to arginase activity

INTRODUCTION Cervical cancer is characterized by an immunosuppressive microenvironment and a Th2-type cytokine profile. Expression of arginase (ASE), the enzyme that converts L-arginine into L-ornithine and urea, is stimulated by Th2-type cytokines. OBJECTIVE To assess the association of ASE activity and L-Arg metabolism products with cervical cancer. METHODS Sera of 87 and 41 women with histologically confirmed by colposcopy-directed biopsy SCC and CIN3 respectively and 79 with normal cytology or Low-Grade Squamous Intraepithelial Lesion (LSIL), were evaluated. Cytokines were measured using Milliplex Human cytokine/chemokine kit. Arginase (ASE) activity was determined using an enzymatic assay. Levels of L-arginine, L-ornithine, putrescine and spermine were determined by HPLC. RESULTS Significantly higher levels of ASE activity were observed in women with CIN3 (age-adjusted OR: 24.3; 95%CI: 3.82-155) and SCC (AOR: 9.8; 95%CI: 2.34-40.8). As expected, possibly due to high levels of ASE activity, higher levels of l-Arg were negatively associated with CIN3 (AOR: 0.03; 95%CI: 0.004-0.19) and SSC (AOR: 0.06; 95%CI: 0.02-0.24). Consistent with the role of ASE in the conversion of L-arginine to L-ornithine and polyamine production therefrom, women with cervical cancer had higher levels of spermine and putrescine. A correlation analysis revealed a significant albeit weak relationship between high levels of IL-10 and high levels of ASE (Pearson r=0.32, p-value=0.003) in women with cervical cancer. CONCLUSION This study indicates that ASE activity and L-Arg degradation mechanisms of immunosuppression are present in cervical cancer. The results foster research in the design of possible strategies to inhibit ASE activity for therapy of cervical cancer.

Distribución de variantes del virus del papiloma humano 16 (VPH 16) en mujeres con y sin neoplasia intraepitelial cervical grado 3 y cáncer cervical

Resumen Objetivos Describir la distribucion de variantes del virus del papiloma humano 16 en mujeres con y sin neoplasia intraepitelial cervical grado 3 y cancer cervical. Metodos Se determinaron las variantes moleculares en casos de carcinoma escamocelular, adenocarcinoma cervical y en mujeres sin anormalidades citologicas de alto grado y positivas para el virus del papiloma humano 16. Para la deteccion de las variantes moleculares se amplifico el marco abierto de lectura del gen E6 del virus del papiloma humano 16 y se utilizo una tecnica de hibridacion reversa para la deteccion de los principales cambios de nucleotidos que identifican las ramas filogeneticas y las clases de variantes. Resultados Hubo diferencias estadisticamente significativas en la distribucion de variantes de virus del papiloma humano 16. Los controles no presentaron infecciones con variantes no europeas , mientras que ellas estuvieron presentes en el 30% de los casos de carcinoma escamocelular o neoplasia intraepitelial cervical grado tres. En adenocarcinoma, el 65% de las infecciones fueron del tipo no europeo . Conclusiones La prevalencia de variantes no europeas de virus de papiloma humano 16 fue de 31,2% en neoplasia intraepitelial cervical grado 3 y cancer escamocelular, y de 64,1% en adenocarcinoma de cervix, mientras que estas no se observaron en mujeres sin cancer.