During the course of HIV infection the number of CD4 cells decreases, resulting in a reduced immunological response and ultimately immune deficiency. Vacc-4x is a peptide-based HIV immunotherapy and the primary objective is to strengthen the immune system's response to HIV p24. By adding Lenalidomide, an immunomodulatory agent, as a supporting drug, it is anticipated that the effect of Vacc-4x might be enhanced.