Trichomonas vaginalis infection and risk of prostate cancer: associations by disease aggressiveness and race/ethnicity in the PLCO Trial.

PURPOSE: Results from previous sero-epidemiologic studies of Trichomonas vaginalis infection and prostate cancer (PCa) support a positive association between this sexually transmitted infection and aggressive PCa. However, findings from previous studies are not entirely consistent, and only one has investigated the possible relation between T. vaginalis seropositivity and PCa in African-American men who are at highest risk of both infection and PCa. Therefore, we examined this possible relation in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, including separate analyses for aggressive PCa and African-American men. METHODS: We included a sample of participants from a previous nested case-control study of PCa, as well as all additional Caucasian, aggressive, and African-American cases diagnosed since the previous study (total n = 438 Gleason 7 Caucasian cases, 487 more advanced Caucasian cases (≥Gleason 8 or stage III/IV), 201 African-American cases, and 1216 controls). We tested baseline sera for T. vaginalis antibodies. RESULTS: No associations were observed for risk of Gleason 7 (odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.55-1.37) or more advanced (OR = 0.90, 95% CI 0.58-1.38) PCa in Caucasian men, or for risk of any PCa (OR = 1.06, 95% CI 0.67-1.68) in African-American men. CONCLUSIONS: Our findings do not support an association between T. vaginalis infection and PCa.

Prospective study of effect modification by Toll-like receptor 4 variation on the association between Trichomonas vaginalis serostatus and prostate cancer.

PURPOSE: In previous studies, we observed a positive association between Trichomonas vaginalis serostatus and risk of prostate cancer, particularly aggressive cancer, which we hypothesized might be due to T. vaginalis-mediated intraprostatic inflammation and cell damage. To explore this hypothesis further, we investigated effect modification by Toll-like receptor 4 (TLR4) variation on this association. We hypothesized that TLR4 variation might serve a marker of the anti-trichomonad immune response because T. vaginalis has been shown to elicit inflammation through this receptor. METHODS: We previously genotyped the non-synonymous TLR4 single nucleotide polymorphism (SNP), rs4986790, and determined T. vaginalis serostatus for 690 incident prostate cancer cases and 692 controls in a nested case-control study within the Health Professionals Follow-up Study. RESULTS: A non-significant suggestion of effect modification was observed by rs4986790 carrier status on the association between T. vaginalis serostatus and prostate cancer risk (p interaction = 0.07). While no association was observed among men homozygous wildtype for this SNP (odds ratio (OR) = 1.23, 95 % confidence interval (CI): 0.86-1.77), a positive association was observed among variant carriers (OR = 4.16, 95 % CI: 1.32-13.1). CONCLUSIONS: Although not statistically significant, TLR4 variation appeared to influence the association between T. vaginalis serostatus and prostate cancer risk consistent with the hypothesis that inflammation plays a role in this association. Larger studies will be necessary to explore this possible effect modification further.

Evaluation of an IgG cystatin capture enzyme-linked immunosorbent assay for the detection of anti-cysteine proteinase antibodies in asymptomatic trichomoniasis patients.

All isolates of T. vaginalis release cysteine proteinases proteolytic enzymes that are shed into the vagina or culture medium. Cystatin has been used successfully as a capture agent in ELISA to detect cysteine proteinase antibodies without the need for purified proteinases. The ELISA was evaluated in comparison to wet mount microscopy and culture techniques. IgG cystatin capture ELISA proved to be a sensitive and highly specific (100%) assay that could rapidly detect anti-cysteine proteinase antibodies in both vaginal washouts and sera of asymptomatic patients with a sensitivity of 100% and 86.7%, respectively. A defined discrimination between sero-positive and sero-negative individuals was markedly observed for ELISA-vaginal washouts providing a more conclusive diagnosis by this technique. The results demonstrated that in trichomoniasis patients (52 cases) whether symptomatic or asymptomatic. T. vaginalis infection was detected in 19 (36.5%), 49 (94.2%), 50 (96.1%) and 48 (92.3%) by wet mount, culture, cystatin capture ELISA-vaginal washouts and ELISA-sera, respectively. The assay was reliable also as a test of cure with a specificity of 94.4% in the vaginal washouts and 83.3% in sera.