Interleukin‐2 Increases CD4⁺Lymphocyte Numbers but Does Not Enhance Responses to Immunization: Results of A5046s

To ascertain whether CD4(+) lymphocyte increases induced by interleukin (IL)-2 enhanced in vivo immune responses, 38 human immunodeficiency virus (HIV)-infected patients who had received highly active antiretroviral therapy (HAART) or HAART and IL-2 for at least 60 weeks were immunized with tetanus toxoid, inactivated glycoprotein 120-depleted HIV-1, and hepatitis A and B vaccines. Despite dramatic increases in CD4(+) lymphocyte counts, IL-2 did not enhance immunization responses.