Could help immune system - by waking up the Thymus (which is responsible for making T cells mature)
clinical trial
http://clinicaltrials.gov/show/NCT00071240
http://www.ncbi.nlm.nih.gov/pubmed/18292808?dopt=Abstract
http://www.ncbi.nlm.nih.gov/pubmed/19479077
http://www.ncbi.nlm.nih.gov/pubmed/18292816?dopt=Abstract
http://www.ncbi.nlm.nih.gov/pubmed/12004268?dopt=Abstract
http://www.aidsmeds.com/articles/hiv_growth_hormone_1667_14093.shtml