Increased CD38 expression on T lymphocytes as a marker of HIV dissemination into the central nervous system

Cross-sectional analysis on 20 HIV-1 patients with neurological symptoms admitted to two infectious disease units. Cut-off of HIV-RNA (VL) was 20 copies/ml for plasma and cerebral spinal fluid (CSF). Flow cytometry was used to analyze the phenotype of circulating and CSF T lymphocytes. CD38 mean fluorescence intensity (MFI) was higher on circulating CD4(+)T lymphocytes from patients with VL>20 copies/ml in plasma (P=0.001) or CSF (P=0.001). The frequency of circulating CD8(+)CD38(+)T cells and CD38 MFI on these cells were higher in patients with VL >20 copies/ml than in those with undetectable plasma VL (P =0.030 and P = 0.023). The frequency of CSF CD4(+)CD38(+)T, as well as their CD38 and CD95 MFI, were increased in patients with detectable than non-detectable plasma VL (P=0.01, P=0.03, and P=0.05). The% CD38(+)CD8(+)T inCSF correlated with time of virological suppression (rho= -0.462, P=0.040) and the CNS penetration-effectiveness (CPE) score (rho=-0.467, P=0.038). In conclusion, (a) the expression of CD38(+) on both CD4(+), CD8(+) T lymphocytes from peripheral blood and CSF discriminated between viremic and non-viremic patients and (b) T cell activation/apoptosis markers inversely correlated with CPE to remark the importance for therapy to restore immunological functions.