Differential patterns of CD4 recovery following effective treatment with HAART

Abstract

CD4 counts rise following treatment with HAART, the pattern of which however varies between individuals and populations. Host, virus and treatment factors may play a part in shaping the trajectory. Through an HIV clinical cohort study, we aim to describe the natural course of CD4 trajectories and evaluate possible factors associated with different patterns. Between 1997 and 2008, HIV‐1‐infected patients receiving HAART at one major HIV specialist clinic in Hong Kong were included in a study for assessing CD4 changes. The entry criteria were: (a) patients who have been put on HAART according to standard criteria; (b) sustained viral suppression after treatment; (c) having been on HAART for at least 48 months. A total of 141 patients with 3,087 measurements were analysed, covering a total of 11,282 person‐months. The median age at initiation of HAART was 37 (IQR 32–44). A majority were male (74%), Chinese (87%) and who have contracted HIV through heterosexual contacts (84%). At baseline, the median CD4 was 39 cells/µL (IQR 13–127 cells/µL) and viral load was 74,100 copies/mL (IQR 26,800–280,000 copies/mL). Over time, 80 (57%) gave a CD4 count of>500/µL during antiretroviral treatment. Clinically, almost all (96%) had presented with an AIDS‐defining illness before HAART was started. Around half of the patients were on 2NRTI+1 NNRTI and half on 2NRTI+1 PI. Overall, 3 groups of patients can be differentiated by their temporal pattern of CD4 recovery. Group One (n=38; 34%) gave a median peak value of 576/µL within 4 years (median interval 40 months). Group Two comprised 96 (68%) patients whose mean CD4 count continued to rise beyond 48 months. Group Three (n=7) gave little or no response to treatment, as defined by a change of<100 cells/µL in the mean count by year. Group Three patients were relatively older (median age=46 years). Comparing between Group One and Two, there was a higher proportion of men having sex with men whose CD4 had plateaued within 4 years (21% vs 6%, p=0.017). Lower baseline CD4 and higher baseline viral load were associated with continued rise of CD4 beyond 4 years. There was no association of CD4 recovery pattern with the HAART regimen. In conclusion, CD4 rise tends to be prolonged following effective virus suppression in a predominantly Chinese HIV population. The differential patterns were largely associated with host factors with little impacts from HAART regimens.