A study gave HIV patients a mix of the drug zidovudine, a protein called thymosin‑alpha‑1, and interferon‑alpha for a year. The combo was safe and led to a noticeable rise in both the number and activity of important immune cells (CD4+ T cells), more than zidovudine alone or with just one of the other agents. This suggests thymosin‑alpha‑1 can boost immune function when used with other treatments, but the research is limited to HIV patients and hasn’t been tested in healthy people.

We have investigated the effects of combination therapy with thymosin alpha 1 and natural human lymphoblastoid interferon-alpha in human immunodeficiency virus infection and have shown that in vitro this combination treatment: (1) synergistically stimulated the cytotoxic activity against natural killer-sensitive target cells of lymphocytes collected from human immunodeficiency virus-infected donors and (2) did not interfere with the antiviral activity of zidovudine. We thus studied the effects of combination therapy with thymosin alpha 1, interferon-alpha and zidovudine in patients with CD4+ lymphocytes ranging from 200 to 500/mm3 in a randomized non-blinded study and found that the treatment was well tolerated after 12 months of therapy and was associated with a substantial increase in the number and function of CD4+ T cells. A similar effect was not observed in human immunodeficiency virus patients treated with zidovudine alone or associated with single agents. These data suggest the need for a controlled, double-blind clinical trial, recently initiated with the approval and the support of the Italian Ministry of Health.