PhotoBio-HIV: Effects of Vascular Photobiomodulation on Inflammatory and Immunological Biomarkers in People Living with HIV – Study Protocol for a Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Abstract People living with human immunodeficiency virus (HIV), even when receiving stable antiretroviral therapy (ART) and maintaining viral suppression, may experience persistent low-grade systemic inflammation associated with premature aging, immune dysregulation, and multimorbidity. Vascular photobiomodulation (PBM) is a noninvasive intervention with potential anti-inflammatory, vascular, and immunomodulatory effects; however, its effects in this population remain insufficiently investigated. This study aims to evaluate the effects of PBM on inflammatory, immunological, hematological, and coagulation biomarkers in this population receiving stable ART and viral suppression. This is a single-center, randomized, double-blind, placebo-controlled clinical trial involving 105 participants allocated to three groups: a Red Group receiving PBM with 637-nm light, a Violet Group receiving PBM with 405-nm light, and a Gray Group undergoing a sham procedure using an identical device with no light output. The intervention will be applied over the radial artery for 10 min, twice weekly for 4 weeks, and repeated in months 1, 3, and 5, totaling 24 sessions over 6 months. Blood samples will be collected at seven time points to assess interleukins, tumor necrosis factor alpha, D-dimer, high-sensitivity C-reactive protein, nitric oxide, CD4 + T-cell count, viral load, and complete blood count parameters. If effective, PBM may represent a safe and promising adjunctive strategy for improving the management of persistent inflammation in HIV care.