Objective: To assess CD4+ cell count recovery in people severely immunosuppressed at start of antiretroviral therapy (ART) who achieve and maintain viral load suppression.
Methods: Eligible participants from the UK Collaborative HIV Cohort Study started ART with at least three drugs after 1 January 2000. Participants were required to have pre-ART CD4+ cell count below 100 cells/μl, at least 2 years of follow-up on ART, have achieved viral load suppression (≤50 copies/ml) by 9 months after starting ART and to have maintained this throughout follow-up. Participants were further required to be regularly engaged with care. We calculated the proportion of people who failed to achieve a CD4+ cell count of more than 100, 150, 200, 350 and 500 cells/μl by the time of the last follow-up, or 5 years from start of ART, whichever occurred first (censoring date).
Results: Of the 400 participants [median (interquartile range) pre-ART CD4+ cell count of 38 (14–65) cells/μl], 2 (0.5%), 8 (2%), 28 (7%), 131 (33%) and 259 (65%) failed to achieve a CD4+ cell count of more than 100, 150, 200, 350 and 500 cells/μl, by the censoring date, respectively. Kaplan–Meier estimates of the proportion of people reaching each CD4+ cell count threshold after 1 year on ART were 88, 70, 50, 14 and 3%, respectively, and after 3 years on ART, 98, 95, 90, 59 and 25%, respectively. Median (interquartile range) follow-up on ART was 3.9 (2.7–4.8) years.
Conclusion: Given a person with pre-ART CD4+ cell count below 100 cells/μl survives and maintains consistent viral load suppression on ART, there is over a 90% chance of reaching a CD4+ cell count above 200 cells/μl by 3 years.