[Quantity and function of regulatory T cells in hemocytopenic patients with positive BMMNC-Coombs test].

OBJECTIVE: To investigate the quantity and function of regulatory T cells in immune related pancytopenia (IRP) and explore the significance of Treg cells in the pathogenesis of IRP.
METHODS: Sixty-six IRP patients and 24 healthy donors were enrolled. The levels of IL-2 and TGF-β were detected by ELISA. The ratios of CD4(+)CD25(+)/CD4(+) and CD4(+)CD25(+)CD127(low)/CD4(+) in bone marrow were examined with flow cytometry. The expressions of Foxp3 and galectin-10 mRNA in BMMNC were measured by semi-quantitative RT-PCR.
RESULTS: The levels of IL-2 and TGF-β in bone marrow of untreated or recovered IRP patients [(5.6 ± 1.7), (6.2 ± 2.5) µg/L, (1.8 ± 0.7), (1.9 ± 0.8) µg/L]were significantly lower than those of healthy controls [(7.9 ± 3.7), (2.5 ± 0.9) µg/L, all P < 0.05]. The ratio of CD4(+)CD25(+)/CD4(+) cells in bone marrow of untreated IRP patients (22.5% ± 9.5%) was significantly lower than that of recovered IRP patients or healthy controls (27.1% ± 7.1%, 30.6% ± 8.6%, both P < 0.05). The ratio of CD4(+)CD25(+)CD127(low)/CD4(+) cells in bone marrow of untreated IRP patients was significantly lower than that of recovered IRP patients or healthy controls (7.2% ± 2.7% vs 9.1% ± 4.7%, 10.4% ± 3.2%, both P < 0.05). The relative mRNA expressions of Foxp3 and galectin-10 were 0.34 ± 0.25, 0.69 ± 0.51, 0.82 ± 0.66 and 0.66 ± 0.11, 0.74 ± 0.11, 0.76 ± 0.09 in three groups respectively. The expressions of two factors in untreated IRP patients were significantly lower than those in recovered IRP patients or normal controls (all P < 0.05).
CONCLUSION: The abnormalities in quantity and function of Treg cells in IRP patients might play an important role in the pathogenesis of IRP.