Genital inflammatory status and the innate immune response to contraceptive initiation.

PROBLEM: Data on the effects of contraceptives on female genital tract (FGT) immune mediators are inconsistent, possibly in part due to pre-existing conditions that influence immune mediator changes in response to contraceptive initiation. METHODS: This study included 161 South African women randomised to injectable depot medroxyprogesterone acetate (DMPA-IM), copper intrauterine device (IUD), or levonorgestrel (LNG) implant in the Evidence for Contraceptive Options and HIV Outcomes (ECHO) trial. We measured thirteen cytokines and antimicrobial peptides previously associated with HIV acquisition in vaginal swabs using Luminex and ELISA, before, and at 1 and 3 months after contraceptive initiation. Women were grouped according to an overall baseline inflammatory profile. We evaluated modification of the relationships between contraceptives and immune mediators by baseline inflammation, demographic, and clinical factors. RESULTS: Overall, LNG implant and copper IUD initiation were associated with increases in inflammatory cytokines, while no changes were observed following DMPA-IM initiation. However, when stratifying by baseline inflammatory profile, women with low baseline inflammation in all groups experienced significant increases in inflammatory cytokines, while those with a high baseline inflammatory profile experienced no change or decreases in inflammatory cytokines. CONCLUSION: We conclude that pre-contraceptive initiation immune profile modifies the effect of contraceptives on the FGT innate immune response.

Microbial function and genital inflammation in young South African women at high risk of HIV infection.

BACKGROUND: Female genital tract (FGT) inflammation is an important risk factor for HIV acquisition. The FGT microbiome is closely associated with inflammatory profile; however, the relative importance of microbial activities has not been established. Since proteins are key elements representing actual microbial functions, this study utilized metaproteomics to evaluate the relationship between FGT microbial function and inflammation in 113 young and adolescent South African women at high risk of HIV infection. Women were grouped as having low, medium, or high FGT inflammation by K-means clustering according to pro-inflammatory cytokine concentrations. RESULTS: A total of 3186 microbial and human proteins were identified in lateral vaginal wall swabs using liquid chromatography-tandem mass spectrometry, while 94 microbial taxa were included in the taxonomic analysis. Both metaproteomics and 16S rRNA gene sequencing analyses showed increased non-optimal bacteria and decreased lactobacilli in women with FGT inflammatory profiles. However, differences in the predicted relative abundance of most bacteria were observed between 16S rRNA gene sequencing and metaproteomics analyses. Bacterial protein functional annotations (gene ontology) predicted inflammatory cytokine profiles more accurately than bacterial relative abundance determined by 16S rRNA gene sequence analysis, as well as functional predictions based on 16S rRNA gene sequence data (p < 0.0001). The majority of microbial biological processes were underrepresented in women with high inflammation compared to those with low inflammation, including a Lactobacillus-associated signature of reduced cell wall organization and peptidoglycan biosynthesis. This signature remained associated with high FGT inflammation in a subset of 74 women 9 weeks later, was upheld after adjusting for Lactobacillus relative abundance, and was associated with in vitro inflammatory cytokine responses to Lactobacillus isolates from the same women. Reduced cell wall organization and peptidoglycan biosynthesis were also associated with high FGT inflammation in an independent sample of ten women. CONCLUSIONS: Both the presence of specific microbial taxa in the FGT and their properties and activities are critical determinants of FGT inflammation. Our findings support those of previous studies suggesting that peptidoglycan is directly immunosuppressive, and identify a possible avenue for biotherapeutic development to reduce inflammation in the FGT. To facilitate further investigations of microbial activities, we have developed the FGT-DB application that is available at http://fgtdb.org/ . Video Abstract.