The defective bone marrow-derived mesenchymal stem cells in patients with chronic immune thrombocytopenia.

Chronic immune thrombocytopenia (ITP) is characterized by autoimmune-mediated platelet destruction and impairment of thrombopoiesis. Mesenchymal stem cells (MSCs) are proposed to exhibit immune modulatory functions in self-tolerance maintenance. In this study, we aimed to characterize phenotypically and functionally bone marrow (BM)-derived MSCs from adult chronic ITP patients. Our results showed that BM-MSCs from patients with chronic ITP exhibited impaired proliferation, abnormal morphology and excessive apoptosis, and these defects could be ameliorated by modifying the culture environment. BM-MSCs from chronic ITP patients were shown to have similar immunophenotype and capacities to differentiate along adipogenic and osteogenic lineages as those from normal controls. However, the immune-inhibiting potential and the regulatory T cell-inducing ability of BM-MSCs from patients were defective compared to that of normal BM-MSCs. These findings suggest that the BM-MSCs were defective in chronic ITP patients. Whether the defective BM-MSCs are relevant to the pathogenesis of chronic ITP remains to be determined.