Abstract
HIV may induce gastrointestinal (GI) mucosal immune dysregulation similar to inflammation observed in ulcerative colitis (UC). Colorectal biopsies from healthy controls (N=12) and from participants with HIV (N=20) or UC (N=9) were subjected to real time (RT)-PCR for selected cytokines, chemokines, antimicrobial peptides, Toll-like receptors, and inflammatory signaling and epithelial barrier proteins. HIV long terminal repeat relative copy number (RCN) in HIV participant biopsies was quantified by RT-PCR. Mean interleukin (IL)-6 mRNA levels did not differ significantly between HIV and UC participants (p=0.48) but were significantly higher relative to control mRNA levels only for HIV participants (p=0.03). Mean IL-8 and human defensin (HD) 5 mRNA levels were similar between HIV and UC participants (p=1.0 and p=0.35, respectively) and were significantly greater in both groups relative to controls (p<0.05 for all). Human beta-defensin (HBD)-2 mRNA levels were higher in UC relative to HIV and control participants (p<0.01 for both). Conversely, HBD-1 mRNA levels were downregulated in UC vs. HIV participants (p=0.01). Mediator gene expression did not differ significantly between HIV participants with detectable (N=10) or nondetectable (N=10) plasma viral loads. Tissue HIV relative copy number (RCN) correlated with plasma viral load (r=0.88, p<0.01) but not with mediator mRNA levels. The results of this study indicate that both chronic HIV infection and UC are associated with similar patterns of IL-6, IL- 8, and HD5 expression in colorectal biopsy tissue. These findings suggest overlapping mechanisms for GI mucosal inflammation in these two illnesses and merit further investigation in larger studies.