CD38 and atherosclerosis: This finding is in contrast to studies in predominantly US cohorts with a high proportion of overweight and obese participants, in which greater T-cell activation (measured by CD38+HLADR+) has been associated with increased arterial stiffness, hypoxia-induced relaxation and increased atherosclerosis.9,12,13,14 Furthermore, most of the associations between T-cell subsets and vascular compliance were not observed in the HIV-negative controls.