VI-28 is a formula of traditional Chinese medicine (TCM) that has been used in aged individuals to improve health and, recently, to treat patients with chronic human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections. The mechanism underlying its clinical effect is, however, largely unknown. In the current study, we used a transwell culture system that mimics the in vivo situation and applied microarray technology to explore the effect of VI-28 on gene expression in human lymphocytes. The VI-28 treatment induced expression of a number of proinflammatory cytokines/chemokines in both peripheral blood mononuclear cells (PBMC) and spleen cells, including interleukin-1 (IL-1), growth-related protein-beta (GRO-beta) and epithelial cellderived neutrophil-activating peptide (ENA-78 [CXCL5]). Furthermore, a specific upregulation of interferon- gamma (IFN-gamma), monokine induced by gamma interferon (MIG [CXCL9]) and interleukin-2 receptor alpha (IL-2Ralpha) in spleen cells was noted, whereas tissue inhibitor of metalloproteinase-3 (TIMP-3) and disabled-2 (DAB2) were downregulated. VI-28 might, thus, enhance both innate and acquired immunity, in particular, T cell function. In addition, genes with no obvious immunologic function, such as insulin-like growth factor-2 (IGF- 1) and CD9, were also differentially affected. Further analysis of individual and combination of ingredients of VI-28 may shed light on the role of this herbal medicine in combating different diseases.