[The role of intracellular signal pathway of mTOR/S6 in CD3+ T lymphocytes of refractory/relapsed aplastic anemia patients].

ABSTRACT

OBJECTIVE: To explore the activation status of signal pathway of mTOR/S6 in bone marrow (BM) T lymphocytes of refractory/relapsed aplastic anemia patients (AA), and the effects of rapamycin (RAPA) and CTLA-4 immunoglobulin (CTLA-4Ig) on this pathway. METHODS: BM was collected from 13 refractory/relapsed AA patients, 8 newly diagnosed severe AA (SAA) patients and 10 iron deficiency anemia (IDA) (as controls) patients, and cocultured with RAPA and CTLA-4 Ig. The expression of p-mTOR, p-S6 and Interferon gamma (IFN-gamma) in CD3(+)T cells was measured by flow cytometry (FCM). RESULTS: (1) The expression of p-mTOR, p-S6 and IFN-gamma in CD3(+)T cells in refractory/relapsed AA group were significantly higher than those in controls (P < 0.01). (2) The expression of p-mTOR and p-S6 in T cells in newly diagnosed SAA group, was similar to those in controls (P > 0.05), but significantly lower than those in refractory/relapsed AA group (P < 0.01). The expression level of IFN-gamma in T cells were significantly higher than that in controls (P < 0.01). (3) On exposure to RAPA, the levels of p-mTOR, p-S6 and IFN-gamma in T cells in refractory/relapsed AA patients were significantly lower than those before the exposure (all P < 0.05). And so were when exposed to CTLA-4 Ig (all P < 0.01). CONCLUSION: (1) The mTOR/S6 signal pathway is activated in refractory/relapsed AA. (2) The expression of p-mTOR, p-S6 and IFN-gamma in refractory/relapsed AA can be suppressed by RAPA or CTLA-4Ig. (3) The signal pathway of CD28/mTOR/S6/IFN-gamma might take part in immune pathogenesis of refractory/relapsed AA.