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 decline in Gag-specific T cell responses preceding detectable viraemia was demonstrated in C13. This decline up to year 16 was followed by a period of low detectable viraemia (50 -100 copies/ml) between years 19 -22. A rebound in these Gag-specific T cell responses coincided with the first detectable viraemia at 19 years. These T cell responses may have helped contain viraemia to low levels over the following two years, but the sharp increase in viral RNA at 22.7 years ( Figure 1 ) coincided with a decline in Gag-specific CD4 and CD8 T cell responses, whereas Pol-specific CTL increased in response to rising viraemia. These examples demonstrate the influence of conserved Gag-specific responses, particularly helper T cell responses, in reduced viral replication and delayed disease progression. While the decline in these responses preceded detectable viraemia in C13, sufficient patient specimens were not available to allow this critical observation to be made in others who progressed.