CD27 and PD ‐1 expression patterns and exploratory ratio‐based immunophenotypic indices in people living with HIV

Abstract Chronic immune activation and T‐cell exhaustion persist in people living with HIV (PLWH) despite effective antiretroviral therapy (ART). We investigated CD27 and PD‐1 expression and evaluated ratio‐based indices as exploratory immunophenotypic indices related to T‐cell differentiation and exhaustion. In this single‐center, analytical cross‐sectional study, 199 PLWH were categorized into BIC/FTC/TAF ( n = 57), DTG/TDF/FTC ( n = 51), DTG/3TC ( n = 39), viremic ( n = 22), and treatment‐naive ( n = 30) groups. CD27 and PD‐1 expression on CD4 + and CD8 + T cells was assessed by flow cytometry. The CD4 + CD27 + /CD4 + PD‐1 + and CD8 + CD27 + /CD8 + PD‐1 + ratios were calculated and correlated with selected clinical and immunological parameters. Significant differences were observed in CD4 + T‐cell count ( p < 0.001), CD8 + T‐cell count ( p = 0.041), CD4 + PD‐1 + percentage ( p = 0.022), CD8 + CD27 + percentage ( p = 0.004), and CD8 + PD‐1 + percentage ( p = 0.001). The CD4 + CD27 + /CD4 + PD‐1 + ratio ( p = 0.019) and CD8 + CD27 + /CD8 + PD‐1 + ratio ( p = 0.010) were highest in the DTG/3TC group and lowest in treatment‐naive individuals. Both ratios showed inverse correlations with age, diagnostic delay, and HIV RNA levels at diagnosis, whereas positive correlations were observed with baseline CD4/CD8 ratio. Higher CD27/PD‐1 ratios were associated with more favorable immunological profiles and preserved immune balance. These ratio‐based indices may have potential as exploratory immunophenotypic indices associated with immune status in PLWH and warrant further validation in prospective studies.