Adrenaline-induced mobilization of T cells in HIV-infected patients

The present study aimed to investigate lymphocyte mobilization from periphe ral cell reservoirs in HIV-infected patients. Nine HIV-infected patients on stable highly active anti-retroviral therapy (HAART), eight treatment-naiv e HIV-infected patients and eight HIV- controls received a 1-h adrenaline i nfusion. The adrenaline infusion induced a three-fold increase in the conce ntration of lymphocytes in all three groups. All HIV-infected patients mobi lized significantly higher numbers of CD8(+) cells but less CD4(+) cells. A ll subjects mobilized CD45RA(+)CD62L(+) and CD8(+)CD28(+) cells to a lesser extent than CD45RO(+)CD45RA(-) and CD8(+)CD28(-)cells. Furthermore, high n umbers of CD8(+)CD38(+) cells were mobilized only in the HIV-infected patie nts. It was therefore predominantly T cells with an activated phenotype whi ch were mobilized after adrenaline stimulation. It is concluded that the HI V-associated immune defect induced an impaired ability to mobilize immune-c ompetent cells in response to stress stimuli. Furthermore, the study does n ot support the idea that CD4(+) T cells are trapped in lymph nodes by HIV a ntigens, because untreated and HAART-treated HIV-infected patients mobilize d similar numbers of CD4(+) T cells. Finally, no evidence was found for the existence of a HAART-induced non-circulating pool of CD4(+) T cells.