Relevance of CD38 Expression on CD8 T Cells to Evaluate Antiretroviral Therapy Response in HIV‐1‐infected Youths

Surrogate markers for monitoring immuno‐virological discordant responders, in addition to plasma viral load and CD4 cells, are still lacking. We assessed the diagnostic utility of CD38 expression on CD8 T cell assay, alone or in association with lymphocyte proliferation to mycotic antigens, in evaluating antiretroviral response. 28 vertically HIV‐infected youths, 21 HAART‐ and seven 2 nucleotide reverse transcriptase inhibitors‐treated, were enrolled in a retrospective study. Responders (57.1%) and non‐responders (42.9%) to stable antiretroviral therapy for a minimum of 6 months, on the basis of viral load and CD4 T cells, comprehensively evaluated by CD38 expression on CD8 T lymphocytes [measured as CD38 antibody bound per CD8 T cell (CD38 ABC) and %CD38+ of total CD8 T cells (%CD38/CD8)] and lymphocyte proliferation to P. jiroveci , C . albicans , C. neoformans , A. fumigatus at a single time point after treatment, were selected. CD38 expression ≥2401 CD38 ABC and ≥85% CD38/CD8 cut‐off points, accurately discriminates responders versus non‐responders, both measures resulting in 75.0% (CI 42.8–94.5) sensitivity (identification of non‐responder) and 93.8% (CI 69.8–99.8) specificity (identification of responder), when considered as single assays. The association ‘≥2401 CD38 ABC or ≥85% CD38/CD8’ improved sensitivity to 83.3% (CI 51.6–97.9), while the association ‘<2401 CD38ABC (or <85% CD38/CD8) and lymphoproliferative response positive to ≥2 tested organisms’ improved specificity to 100% (CI 79.4–100). In conclusions, CD38 expression and mycotic antigen‐specific T‐cell proliferation may be used as additional parameters to existing criteria to evaluate antiretroviral response in immuno‐virological discordant patients.