ABSTRACT
AIM: To investigate the effects of both Th1/Th2 imbalance and its re-attainment on in vitro expansion and hematopoiesis of CD34+ cells from a severe aplastic anemia (sAA) patient. METHODS: A preliminary-diagnosed sAA patient was studied. (1) Bone marrow mononuclear cells (BMMNC) were isolated and CD34+ and CD4+ cells were enriched by magnetic beads respectively. (2) The Th1/Th2 cell ratio within CD4+ subset was detected by flow cytometry (FCM). (3) Enriched-CD34+ cells were expanded and re-enriched for enough cells to be divided into four groups: control, Th cell treatment, Th cell and IFN-gamma treatment, and Th cell and IL-4 treatment, respectively. (4) After expansion for 10 d, colony-forming unit assay was performed on cells in each group. (5) Patient's Th1/Th2 ratio was followed up by FCM after immunotherapy. RESULTS: (1) Symptom remission was achieved after therapy for 5 months. (2) Th1/Th2 cell ratio of the patient before and after remission was 22.47 and 12.27, respectively, while that of healthy controls was 8.98+/-4.45. (3) The CD34+ cell expansion rates as well as CFU numbers, from high to low, were ranked as control, Th cell and IL-4 contained group, Th cell contained, and Th cell and IFN-gamma contained group. CONCLUSION: Predominant Th1 cells seem to directly inhibit the self-renewal, proliferation and lineage differentiation of CD34+ cells in vitro, which can be counteracted by IL-4, probably mediated by switching Th1/Th2 balance.