[In vitro induction of allo-T lymphocytes proliferation by myeloid dendritic cells in patients with severe aplastic anemia.].
OBJECTIVE
To investigate the function of myeloid dendritic cells (mDCs) from severe aplastic anemia (SAA) patients in stimulating allogeneic T lymphocytes proliferation in vitro and then explore the immunopathogenesis of SAA.


METHODS
Twenty-five SAA patients (15 untreated and 10 recovered after immunosuppressive therapy) and 12 normal controls were enrolled in this study. Their mature mDCs were induced from their bone marrow monocytes with recombined human interleukin-4 (rhIL-4), recombined human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and recombined human tumor necrosis factor (rhTNF) in vitro. Then mDCs were co-cultured with allogeneic lymphocytes (mixture lymphocyte reaction, MLR) at a ratio of 1:100 or 1:50. The growth rate of lymphocyte was measured with methyl thiazolyl tetrazolium (MTT) colorimetry. The concentrations of interleukin (IL)-12 and interferon gamma (IFNgamma) in MLR supernatant were measured with ELISA. The correlation between the growth rate and the concentration of IL-12 or IFNgamma was analyzed.


RESULTS
When mDCs and lymphocytes were co-cultured at the ratio of 1:100, the growth rates of lymphocytes stimulated with mDCs from untreated, recovered SAA patients and controls were (219.8 +/- 94.0)%, (159.1 +/- 66.0)% and (160.1 +/- 91.9)% respectively. The concentrations of IL-12 in MLR supernatant were (8.2 +/- 3.6) ng/L, (6.5 +/- 2.8) ng/L and (6.1 +/- 2.6) ng/L and the concentrations of IFNgamma were (21.8 +/- 8.7) ng/L, (25.5 +/- 9.1) ng/L and (22.6 +/- 7.8) ng/L respectively. All of them had no statistical differences among the three groups (P > 0.05). When mDCs and lymphocytes were co-cultured at the ratio of 1:50, the growth rate of lymphocytes stimulated with mDCs from untreated patients was (322.1 +/- 171.1)%, which was higher than that of recovered patients [(180.9 +/- 79.1)% and controls (192.3 +/- 91.9)%]. The concentrations of IL-12 in MLR supernatant in the three groups were (12.6 +/- 4.4) ng/L, (9.4 +/- 3.3) ng/L and (8.5 +/- 3.7) ng/L, and the concentrations of IFNgamma were (32.3 +/- 9.2) ng/L, (27.4 +/- 6.5) ng/L and (24.4 +/- 7.4) ng/L. Both of the values in untreated cases were higher than those of the recovered cases or controls (P < 0.05), but there were no statistical difference between the recovered and control groups (P > 0.05). The concentration of IL-12 in MLR supernatant correlated positively with the growth rate of lymphocyte (r = 0.529, P < 0.01) and so did the concentration of IFNgamma (r = 0.381, P < 0.05).


CONCLUSIONS
The function of mDCs to stimulate T lymphocytes proliferation in SAA was enhanced; it might play an important role in the immunopathogenesis of SAA.
Wang
Jun
J
Department of Hematology & Oncology, Tianjin Medical University General Hospital, Tianjin 300052, China.
Shao
Zong-Hong
ZH
Fu
Rong
R
Wu
Yu-Hong
YH
Xing
Li-Min
LM
Wang
Hua-Quan
HQ
D000741:Anemia, Aplastic; D002478:Cells, Cultured; D003713:Dendritic Cells; D006801:Humans; D018664:Interleukin-12; D015847:Interleukin-4; D013601:T-Lymphocytes
D018664:Interleukin-12; D015847:Interleukin-4