OBJECTIVETo study the quantity and ratio of Th1, Th2 cells in the bone marrow of myelodysplastic syndromes (MDS) patients, and to evaluate the correlation between the ratio of the blast cells and the number of the Th1 cells in the bone marrow of MDS patients.

METHODSBy FACS, the quantity and ratio of IFN-gamma producing CD4(+) T cell (Th1) and IL-4 producing CD4(+) T cell (Th2) cells in the bone marrow were detected in 21 MDS patients, 18 normal controls and 13 severe aplastic anemia (SAA) patients respectively. The karyotypes of 18 MDS patients and 15 normal controls were assayed. The correlation between the ratio of the blast cells in the bone marrow and the number of the Th1 cells in the MDS patients were analyzed.

RESULTSThe percentages of Th1 cells, Th2 cells and ratio of Th1/Th2 in the bone marrow of normal controls were (0.48 +/- 0.10)%, (0.24 +/- 0.19)% and 2.31 +/- 0.76 respectively, while those of the MDS patients were (0.36 +/- 0.11)%, (0.76 +/- 0.35)% and 0.51 +/- 0.13. The percentage of Th1 cells of patients with MDS was reduced and the Th1/Th2 ratio was significantly lower than that of normal controls (P < 0.01). Those of the patients with SAA were (4.75 +/- 0.49)%, (0.40 +/- 0.28)% and 26.5 +/- 8.79 respectively, their Th1 cells and Th1/Th2 ratio were markedly higher than those of normal controls (P < 0.01). In all of the 15 normal controls the karyotypes were normal, but that of MDS patients was (50.00 +/- 0.10)%. The lower ratio of the Th1 cells in the bone marrow of the patients with MDS and the AML which progressed from MDS was negatively correlated with the higher percentage of the blast cells (r = -0.563, P < 0.01).

CONCLUSIONS(1) The immune function of T lymphocytes in MDS is abnormal: the balance between Th1 and Th2 cells is broken. (2) With descending of the number of Th1 cells in the bone marrow of the MDS patients, the disease is progressing to leukemia.