Cervical microbiome in postpartum HIV-positive women
So far, the study of the postpartum cervicovaginal microbiota community has been neglected in HIV-positive women while it is known that they have an increased risk of contracting human papillomavirus (HPV) infection which is the major risk factor for cancerous lesions.
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For the first time9, scientific data were obtained regarding the cervicovaginal microbiota in postpartum HIV-positive women. They showed that postpartum HIV-positive women have a highly diverse microbiota, just like postpartum HIV-negative women. They also showed that immunodeficiency caused by HIV and cervicovaginal dysbiosis are suspected to play a role in the onset of precancerous lesions.
HIV and increased risk of lesions
Vaginal microbiota dominated by Lactobacillus crispatus is associated with a decreased risk of HIV infection and, in HIV-positive women, to a decreased risk of HPV infection. On the contrary, vaginal dysbiosis with higher bacterial diversity and decreased levels of lactobacilli increases the risk of HIV and HPV acquisition, cervical precancerous lesions and cervical cancer. It is also known that a change in vaginal microbiota composition occurs during the postpartum period: higher bacterial diversity and decreased levels of Lactobacillus crispatus. As a result, postpartum HIV-positive women have a vaginal microbiota that could expose them to a higher risk of HVP infection and thus to a higher risk of cervical precancerous lesions and cervical cancer.
What is the role of the microbiota?
To test this hypothesis, Brazilian researchers analyzed the vaginal microbiota of 80 young HIV-positive women on antiretroviral therapy at 6 and 12 months postpartum: four types of microbiota were identified, including three with a high microbial diversity, but none dominated by Lactobacillus crispatus. The researchers observed an overabundance of specific bacteria in cases of cervical precancerous lesions, especially Moryella and Schlegellela. They also detected an increased content of Gardnerella vaginalis in women whose lesions had regressed during the monitoring period, but not in women who had developed lesions
It is not clear from these findings whether the identified bacteria are the cause or the result of cervical precancerous lesions, but this study still highlighted HIV-positive women’ susceptibility and described the type of microorganisms involved. Their exact role in the development of lesions has yet to be determined, bearing in mind that cervical cancer is the 4th most common type of female cancer, causing more than 200,000 deaths every year in the world.
9. Curty G, Costa RL, Siqueira JD, Meyrelles AI, Machado ES, Soares EA, Soares MA. Analysis of the cervical microbiome and potential biomarkers from postpartum HIV-positive women displaying cervical intraepithelial lesions. Sci Rep. 2017 Dec