IFN-γ production by T cells in response to PHA in HAART treated patients at baseline and at weeks 12, 24 and 48. Results are expressed as the mean number of SFC per 106 PBMC of duplicate cultures with variation among duplicates <10%. The positive threshold of ≥ 20 SFC per 106 PBMC is indicated. Box-plots show the median and IQR, and whiskers represent the 10th–90th percentiles. Symbols are specific to each patient according to the key shown in Additional file 1. Randomisation into three groups performed at week 12 is represented by different colours. Group A (red) received placebo, group B (purple) received alternate day dosing of rhGH and group C (blue) received twice weekly dosing of rhGH.