Association of HIV neutralizing antibody with lower viral load after treatment interruption in a prospective trial (A5170)

Nicastri et al.[1] raise an interesting point that perhaps the neutralizing antibody response is increased only against the autologous isolate because it is a ‘recall’ response and induction might be more rapid. We did not evaluate this in our study. There is convincing evidence indicating that autologous neutralizing antibodies lag behind virus evolution [2–6]. On the contrary, broadly neutralizing antibodies are often identified using heterologous isolates. Further, they are generally specific for more conserved regions of the envelope and have been associated with protection in nonhuman primates and are found in long-term nonprogressors and a fifth of all chronically infected persons [7–9]. We had previously reported increases in neutralizing antibody with long-term combination antiretroviral therapy [10]. We postulated that this might have an effect in controlling virus after discontinuation of combination antiretroviral therapy; however, we only saw an effect on viral load. It may be, as Nicastri et al.[1] suggest, that the use of both heterologous and autologous viruses might be a better measure of the breadth of neutralizing antibody responses to consider in the setting of structured treatment interruption. Acknowledgements Conflicts of interest There are no conflicts of interest.