Fecal Calprotectin is Elevated in HIV and Related to Systemic Inflammation.

Background Fecal calprotectin (FC), a biomarker of gastrointestinal inflammation, is used in the diagnosis and management of inflammatory bowel disease (IBD). HIV infection severely damages gut-associated lymphoid and epithelial tissues leading to gastrointestinal inflammation which drives systemic inflammation and increases subsequent risk of co-morbidities. For the first time, we compared FC concentrations by HIV and antiretroviral therapy (ART) status and determined the relationship to systemic inflammation. Methods People with and without HIV were enrolled and underwent a comprehensive clinical and laboratory assessment. Stool samples were collected, and FC was measured by ELISA. Plasma biomarkers of inflammation were also measured. Results 101 participants with HIV (83 ART-treated; 18 ART-naive) and 89 uninfected controls were enrolled. There were no significant differences between ART-naive and ART-treated participants, but both HIV groups had significantly higher FC concentrations compared to controls when FC was considered as a continuous variable or by cut-offs used in IBD. The highest median and largest proportion of participants with FC >100 µg/g were seen in ART-naive followed by ART-treated and then controls. Among HIV participants, FC concentrations were positively associated with high-sensitivity C-reactive protein, soluble tumor necrosis factor-II, and soluble vascular cellular adhesion molecule and inversely associated with CD4 counts. Conclusion FC concentrations are elevated in HIV regardless of ART status. ART and immune reconstitution appear to reduce FC but not to concentrations seen in uninfected controls. Our results suggest a role for FC as a non-invasive surrogate measurement of GI inflammation and associated systemic inflammation in HIV.