Salivary Cytokine Interactome Reveals TREM-1 Upregulation during HIV Infection

Objectives: To compare oral cytokine interactions and EBV secretion in saliva during HIV infection in therapy-naïve and antiretroviral therapy(ART) receiving individuals and a healthy control.

Methods: Unstimulated saliva was obtained from 100 HIV+ volunteers undergoing ART, 20 HIV+ volunteers without ART and a healthy control. All volunteers were non-smokers and were free of oral pathoses. Salivary supernatants were analyzed for 36 cytokines using protein arrays. Cytokine interactomic maps were generated using IPA ingenuity database. Salivary cell pellet was sorted for CD80⁺(FITC) and CD19⁺(PE) cells using flow-cytometry. EBV was quantified using real-time PCR. EBV was imaged by immunofluorescence microscopy and TEM using antibodies against VCA and EA.

Results: HIV infected individuals showed significantly higher EBV copies (4×10⁶±6.9×10³copies/ml) in cells isolated from saliva than healthy (1874±3.1×10³copies/ml)(P<0.00001). 24/36 cytokines were expressed in HIV group without ART, 22/36 in HIV group with ART and 14/36 in healthy. Interactomic maps generated using salivary cytokine expression levels revealed a highly significant upregulation of TREM-1 signaling in both HIV groups compared to healthy (P<0.00001). Flow-cytometry demonstrated a higher monocyte(CD80⁺) population in saliva in HIV groups (0.098%) than healthy (0.011%). 7-15% of epithelial cells in saliva showed nuclear localization of VCA in individuals with >10⁶EBV copies/ml.

Conclusion: TREM-1, a recently discovered innate immunity regulator that induces monocyte trafficking is significantly upregulated during HIV infection. Monocyte transport of EBV to oral epithelium has previously been demonstrated. Thus, TREM-1 upregulation can increase EBV trafficking to oral epithelial cells that are subsequently shed in saliva at high viral loads. Thus, TREM‐1 blockers may prove useful as a novel group of anti-EBV thereapetics.