Assessment of in vitro MK differentiation from control and FPD/AML patient CD34⁺ cells. CD34⁺ peripheral blood cells from AII-1, AII-2, BII-2, BII-3, DIII-1, and DIII-3 patients and from 3 healthy individuals (C) were grown in liquid medium containing TPO, IL-3, IL-6, SCF, and FLT3-L. (A-C) One experiment was performed for each patient; the results obtained for all 6 patients were used for the calculation of statistics. (A) Flow cytometry analysis was performed at day 10 of culture. Percentage indicates the proportion of immature (CD41⁺CD42⁻) and mature (CD41⁺CD42⁺) MKs (n = 3 for controls and n = 6 for patients, P < .05). (B) Absolute number of MKs was calculated at day 10 of culture. The calculation was based on the total cell number at day 1 and day 10 of culture, and on the percentage of mature (CD41⁺CD42⁺) MKs (A). As the number of cells seeded at the day 1 was not identical, the absolute number was estimated per 3 × 10⁴ seeded CD34⁺ cells (n = 3 for controls and n = 6 for patients, P < .05). (C) The ploidy of mature (CD41⁺CD42⁺) MKs was analyzed for 3 controls and 6 patients at day 10 of culture (n = 3 for controls and n = 6 for patients, P < .001). (D) Cytologic investigations of the bone marrow of AII-1, BII-2, and DIII-3 patients. The numerous atypical hypolobulated MKs (black arrows) and microMKs (white arrows) are present.