Disclosed are pharmaceutical compositions and related methods for treating a subject with a viral or retroviral infection. The disclosed compositions and methods comprise and utilize an effective amount of one or more vanadium-containing compounds and an effective amount of one or more sulfonylureas. In certain embodiments, the viral infection is human immunodeficiency virus (HIV) and the compositions and methods improve one or more immunologic cellular parameters, such as viral load, CD4 counts and CD4/CD8 lymphocyte cell ratios in a subject. Also disclosed are methods of improving one or more immunologic cellular parameters that are associated with viral infections such as HIV in a subject, including viral load, CD4 counts and CD4/CD8 lymphocyte cell ratios.