Decreased in vitro megakaryocyte colony formation in chronic idiopathic thrombocytopenic purpura.

In vitro megakaryocyte colony formation was studied in 25 patients with chronic idiopathic thrombocytopenic purpura (ITP), and compared to 16 controls. A significantly lower number of megakaryocyte progenitors (CFU-MK) was observed in patients (10.8 +/- 12.0 CFU-MK per 10(5) bone-marrow non-adherent mononuclear cells (NAMC), compared to controls (22.5 +/- 15.4 CFU-MK); P < 0.002. Only six patients had a normal number of CFU-MK. The number of CFU-MK was not correlated to initial platelet count (P = 0.35). These findings indicate that in vitro CFU-MK could be of interest in the diagnosis of chronic ITP, and also could be predictive for chronicity in patients with acute ITP.