Favorable response of chronic refractory immune thrombocytopenic purpura to mesenchymal stem cells.

Seven patients with chronic refractory immune thrombocytopenic purpura (ITP) received adipose tissue-derived mesenchymal stem cells (AMSC) from haplo-identical family donors. The AMSC dose was 2.0×10(6)/kg. No side effects were noted after the AMSC infusions. Overall responses were reached in all patients and sustained response rate was 57.1% (4/7). The serum levels of transforming growth factor β1 (TGF-β1), interleukin (IL)-4, and IL-10 were significantly elevated, whereas those of interferon-γ (IFN-γ) and IL-2 were significantly decreased after AMSC administration, compared with those in the patients with active ITP. During follow-up, the cytokine profiles in patients maintaining sustained response remained stable compared with the post-treatment level, but IFN-γ and IL-2 levels were significantly increased, and those of TGF-β1, IL-4, and IL-10 were significantly reduced again in relapsed patients. AMSC therapy seems to represent reasonable salvage treatment in severe, chronic refractory ITP by causing a shift in the Th1/Th2 cytokine balance to the same levels as normal controls.