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

Early studies on this cohort of TAHIV patients led to the identification of the Sydney Blood Bank Cohort (SBBC) of long-term survivors [8] , and that an attenuated nef-deleted strain of HIV-1, transmitted from a single donor resulted in slow to non-progression in these individuals [9] . However, after prolonged infection, not all SBBC members maintained non-progressive disease [10] [11] [12] [13] . Although HLA type did not explain non-progression in this group [14] , we have observed differences in CD8 T cell responses that are associated with HLA-dependent epitope recognition [15] , and we have detected increased preservation of helper T cell responses in non-progressors from this cohort [16, 17] . In addition to the well described host genetic factors which may prolong non-progression [7] , recent studies have suggested an influence from innate immune mechanisms, including polymorphisms that decrease TLR function thereby reducing immune activation upon exposure to infections diseases [18] , or the FcγRIIA polymorphism (R/R) which is strongly associated with progressive HIV disease as a result of impaired elimination of HIV immune complexes [19] .