Abstract
Background aims
Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by an accelerated destruction of platelets as a result of the presence of autoreactive antibodies. Patients with ITP also display activated platelet-autoreactive T cells. Mesenchymal stem cells (MSC) inhibit both T- and B-cell activation and may have functional impairments in autoimmune disorders.
Methods
We analyzed the potential role of MSC in the pathogenesis of ITP.
Results
MSC from ITP showed an impaired proliferative capacity and a lower capability of inhibiting activated T-cell proliferation compared with healthy donors. While MSC from controls showed a decreased expression of p27 after stimulation with platelet-derived growth factor, this effect was not observed in MSC from patients. Furthermore, MSC from healthy donors down-regulated p16 upon exposure to platelet-released supernatant, while this effect was not observed for ITP. Interestingly, caspase 9 expression was higher in MSC from ITP.
Conclusions
These abnormalities suggest a role of MSC malfunction in the physiopathology of the disease and may have therapeutic implications.
Acknowledgements
This project was supported by a Grant from the Gerencia Regional de Salud de Castilla y Leon, SACYL 2004 and HUS04A07; M. Díez-Campelo and B. Blanco were supported by a fellowship from the Instituto de Salud Carlos III.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.