Abstract: Objective: To observe the distribution of Th1/Th2 subsets in CD4⁺T cells of cytokine-induced killer (CIKs). Methods: After large scale of amplification of CIKs, CD4⁺T cells subset was isolated by magnetic beads separation columns, and the proportion of IFN- Yand IL- 4 secreting cells were analyzed by intracellular cytokine staining. The cytokines of Th1 kind and Th2 kind, released by purified CD4⁺T cells from the CIKs or PBMCs, were detected by E L I S A and fluorescent real- time quantitive RT-PCR methods. Results: Purity of enriched CD4⁺T cells reached 96%. Comparing with PBMCs,a significant increase (P<0.05) in Th1 subset (IFN- γ⁺IL- 4- cells) and Th0 subset (IFN-γ⁺IL- 4⁺ cells)was respectively observed while no statistical change (P>0.05) was found in Th2 subset (IFN-γ⁺IL- 4⁺cells)in CD4⁺ CIKs. Secretion of Th1 kind of cytokines, such as IL-2 and IFN- γin CD4⁺T cells of CIKs enhanced significantly, and Th2 kind of cytokines, such as IL-10 and TGF-β decreased obvious-ly (P<0.05). Except for IFN- Y, no increase in m RNA synthesis of IL- 2 or IL- 4 was observed in CD4⁺T cells in CIKs compared to PBMCs. Conclusion: This study indicates that a distinct "Th1 dominance"exists in CD4⁺T cells of CIKs.