Mechanisms of HIV non-progression; robust and sustained CD4+ T-cell proliferative responses to p24 antigen correlate with control of viraemia and lack of disease progression after long-term transfusion-acquired HIV-1 infection

Dyer, Wayne B; Zaunders, John J; Yuan, Fang Fang; Wang, Bin; Learmont, Jennifer C; Geczy, Andrew F; Saksena, Nitin K; McPhee, Dale A; Gorry, Paul R; Sullivan, John S

A cohort of blood product recipients with transfusionacquired HIV (TAHIV) infected between 1981 and 1984 was followed prospectively by the Australian Red Cross Blood Service HIV Lookback Team since 1987. There are individuals in this cohort who have remained asymptomatic for 27 years since infection without antiretroviral therapy; some maintaining plasma HIV RNA levels to below detectable levels and a stable CD4 T cell count, thus retaining elite non-progressor status. Early natural history studies on this and other cohorts suggested that TAHIV infection may result in a shorter time to AIDS than sexually-acquired (SA) HIV infection [1, 2] . This observed increase in the rate of disease progression in TAHIV may be due to the higher inoculation volume of blood product compared with the much smaller blood or genital fluid exchange involved in SAHIV infection [1] , as well as the known immunomodulatory effect of transfusion on immune function [3, 4] . Age is also an independent predictor for an increased rate of HIV disease progression [5, 6] . The bias toward an aged population requiring transfusion is part of the composite disadvantage of transfusion as a route of HIV infection [1] . In addition to HIV infection, survival may be influenced by the underlying medical cause for transfusion. Yet despite these disadvantages, we previously observed a high frequency of nonprogression in this TAHIV cohort after 20 years of infection [7] .