Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.28.221325v1?rss=1 Authors: Wanjalla, C. N., Guo, L., Fuller, D. T., Mashayekhi, M., Bailin, S., Gabriel, C. L., Temu, T., Gong, J., Liang, Y., Virmani, R., Finn, A. V., Kalams, S. A., Mallal, S. A., Miner, J., Beckman, J. A., Koethe, J. R. Abstract: Background: Chronic innate and adaptive immune activation may contribute to high prevalence of cardiovascular disease in persons living with HIV (PLWH). Methods: We assessed coronary plaques from deceased PLWH (n=6) and HIV-negative (n=6) persons matched by age and gender. Formalin-fixed, paraffin-embedded 5um thick sections were processed using Movat, hematoxylin and eosin, immunohistochemical and immunofluorescence stains. Immune cell populations were measured using surface antibodies, and immune-related protein expression from macrophage rich, T-cell rich and perivascular adipose tissue regions using digital spatial profiling. Results: Coronary plaques from PLWH and HIV-negative persons had similar plaque area and percent stenosis. Percent CD163+ cells as measured by immunohistochemical staining was significantly higher in PLWH, median 0.29% (IQR 0.11-0.90) vs. 0.01% (IQR 0.0013-0.11) in HIV-negative plaque, p = 0.02 (Figure 1A). Other surface markers of innate cells (CD68 +, p=0.18), adaptive immune cells (CD3+, p=0.39; CD4+, p=0.09; CD8+, p=0.18) and immune trafficking markers (CX3CR1+, p=0.09) within the coronary plaque trended higher in HIV-positive plaques but did not reach statistical significance. Digital spatial profiling showed higher differential protein expression of CD163 (scavenger receptor for hemoglobin-haptoglobin complex), stimulator of interferon gamma (STING, a cytosolic DNA sensor), CD25 and granzyme-B in the HIV-positive compared to HIV-negative, p<0.05(Figure 1B). Conclusions: Increased inflammation within the coronary plaques of PLWH is characterized by more innate and adaptive immune cells. Higher STING expression in PLWH suggests that immune response to viral antigens within the plaque might be a driver above other stimulants. STING inhibitors are available and could be investigated as a future therapeutic target in PWH if these results are replicated with a larger number of plaques. Copy rights belong to original authors. Visit the link for more info