This study assessed whether opioid-use disorder (OUD) is associated with ongoing immune abnormalities among people living with HIV (PWH) who receive optimized antiretroviral therapy (ART). Investigators observed that PWH with OUD (PWH/OUD+) retained systemic and cellular immune dysregulation even after ART reduced HIV viral load (VL). Key plasma markers of monocyte activation and chemotaxis remained elevated, while regulatory cytokines were altered. Functional testing showed impaired monocyte responses to bacterial stimuli, suggesting durable innate immune dysfunction linked to opioid exposure.
Peripheral blood samples were collected longitudinally from PWH/OUD+ at three time points during 6 months of optimized ART (months 0, 3, and 6). A reference cohort of PWH without OUD (PWH/OUD−) who had suppressed HIV VL provided a single blood sample for comparison. Immune profiling comprised measurements of plasma inflammatory biomarkers, multiplex cytokine assays, spectral flow cytometry for cellular phenotyping, and ex vivo stimulation of monocytes with lipopolysaccharide (LPS) to assess cytokine responses. Analyses included mixed-effects models adjusted for HIV VL and VL-stratified comparisons.
Compared with the reference cohort, PWH/OUD+ displayed persistent elevation of several plasma markers despite reductions in HIV VL with ART. Soluble markers associated with monocyte activation—sCD163 and sCD14—remained elevated in PWH/OUD+. Chemokines including fractalkine and I-TAC were also persistently higher. In contrast, the regulatory cytokine TGF-β1 was reduced in PWH/OUD+. These differences indicate a pattern of sustained systemic inflammation and altered chemotactic signaling in the context of opioid exposure.
Cellular profiling demonstrated expansion of CD16⁺ monocytes among PWH/OUD+. Surface expression of trafficking and activation markers on monocytes was altered: CCR2, CD38, and CD11b expression differed in the OUD group relative to the reference cohort. Functionally, monocytes isolated from PWH/OUD+ exhibited attenuated cytokine production after LPS stimulation, indicating diminished innate immune responsiveness to a canonical bacterial stimulus. Together, phenotypic and functional monocyte abnormalities support an effect of opioid exposure on innate immune cells that persists during ART.
Beyond monocytes, the study found persistent alterations across adaptive and innate lymphoid compartments in PWH/OUD+. Markers of activation, metabolism, and trafficking were changed on CD4⁺ and CD8⁺ T cells, as well as on natural killer (NK) cells and B cells. Although specific marker values and exact magnitudes were reported in the original data, the overall pattern indicates broad immune perturbation affecting multiple cell types in PWH with OUD despite ART-mediated decreases in VL.
Investigators used mixed-effects models that adjusted for HIV viral load to evaluate associations between OUD and immune measures. They also performed analyses stratified by viral load. These approaches were intended to separate effects attributable to ongoing HIV replication from those associated with OUD itself. The persistent immune differences observed in PWH/OUD+ after adjustment suggest opioid exposure contributes independently to chronic immune dysregulation in this population.
The findings indicate that opioid-use disorder is associated with persistent systemic and cellular immune dysfunction in people living with HIV, even when ART reduces viral load. Elevated monocyte activation markers, altered chemokine patterns, expansion of CD16⁺ monocytes, broad lymphoid cell perturbations, and blunted monocyte responses to LPS collectively suggest that opioid exposure may perpetuate inflammation and immune dysfunction. The authors conclude that OUD could be an independent contributor to long-term HIV-associated comorbidities through sustained immune dysregulation. Details of effect sizes, participant numbers, and other quantitative results are presented in the full preprint.
Funding and disclosures: The authors reported NIH grant support and declared no competing interests. The study is presented as a bioRxiv preprint and represents results prior to peer-reviewed publication.