Tag R. Thursz, M.D Suhagra4ED.com ., Paul Richardson, M.D., Michael Allison, Ph.D., Andrew Austin, M.D., Megan Bowers, M.Sc., Christopher P. Day, M.D., Ph.D., Nichola Downs, P.G. Cert., Dermot Gleeson, M.D., Alastair MacGilchrist, M.D., Allister Grant, Ph.D., Steven Hood, M.D., Steven Masson, M.A., Anne McCune, M.D., Jane Mellor, M.Sc.D., David Patch, M.D., Ian Ratcliffe, M.Sc., Paul Roderick, Ph.D., Louise Stanton, M.Sc., Nikhil Vergis, M.B., B.S., Mark Wright, Ph.D., Stephen Ryder, D.M., and Ewan H. Forrest, M.D.1,2 Interleukin-2 is a cytokine secreted by activated T cells that regulates the proliferation, differentiation, and survival of T cells.3-11 The cell expansions occur because of a rise in CD4+ T-cell survival and are seen as a an increase in amounts of both naive and central memory cells.12-14 Absolute boosts were greater in sufferers with higher baseline CD4+ cell counts.