Douching Is Associated with Dysregulated Rectal Mucosal Immunity in Sexual Minority Men

Background Receptive condomless anal sex (CAS) associates with elevated rectal inflammation and mucosal injury, increasing HIV acquisition risk. Although douching may amplify rectal inflammation and alter microbial communities, this has not been well characterized in sexual minority men (SMM). Methods Ninety-two SMM (median age, 34.6 years) who were HIV negative and reported receptive CAS provided rectal swabs during sexually transmitted infection (STI) clinic visits. Associations among rectal douching, rectal cytokine/chemokine levels, and microbial communities, evaluated via immunoassay and 16S rRNA gene sequencing, respectively, were assessed. Results When compared with nondouching SMM (n = 27), SMM who douched (n = 64) reported more receptive CAS partners and displayed elevations in rectal cytokine/chemokines linked to immune activation and inflammation. Lower microbial richness, evenness, and Shannon diversity in SMM who reported douching were observed. Significant associations were identified between microbial alpha diversity metrics and rectal chemokine/cytokine levels. Finally, significant correlations were observed between rectal cytokine/chemokine levels and individual microbial genera. Conclusions Among SMM engaging in receptive CAS, douching may identify those with amplified biobehavioral HIV and STI risk. Elucidating the mechanisms whereby douching dysregulates rectal immune function and alters rectal microbial communities could yield targets for biomedical approaches to optimize HIV/STI prevention in SMM during receptive CAS.