Natural history of HIV-control since seroconversion.

OBJECTIVES

HIV-controllers spontaneously maintain HIV viremia at an undetectable level. We aimed to describe the delay to control from seroconversion, the duration of control, and risk factors for losing control.

METHODS

HIV-controllers were identified from a pooled dataset of 24 seroconverter cohorts from Europe, Australia, and Canada (CASCADE). HIV-controllers had at least five consecutive viral loads less than 400/500 copies/ml, while antiretroviral therapy naive, for at least 5 years after seroconversion. End of control was defined as two consecutive viral loads above 2000 copies/ml. Duration of control was described using Kaplan-Meier estimates; factors associated with duration of control were identified using a Cox model. CD4⁺ cell count evolution during control was described using a mixed model.

RESULTS

Of 9896 eligible seroconverters, we identified 140 (1.4%) HIV-controllers, the largest database of HIV-controllers followed from seroconversion. For 64 with viral load measured within 24 months from seroconversion, median delay to control was 16.7 (interquartile range: 7.8-37.9) months. Probability of maintaining control 20 years after seroconversion was 0.74 [95% confidence interval (CI): 0.64-0.85]. Occurrence of blips followed by return to undetectability did not increase the risk of loss of control [hazard ratio: 0.81 (95% CI: 0.10-6.70)]. However, CD4⁺ cell loss during control was significantly accelerated in individuals with blips.

CONCLUSION

In most individuals, control occurred rapidly after seroconversion; however, more than 3 years were required to achieve control in 25% of HIV-controllers. Control may be sustained even when CD4⁺ cell levels are below 500 cells/μl, opening important new perspectives to understand the physiopathology underlying control.