Late release of PF4 and βTG in the supernatant of megakaryocytic cell cultured from CB-CD34⁺ cells.

The concentration of PF4 and βTG was measured by immunoenzymatic assay in the supernatants of MK cultures obtained from CB (▪) and PB (■) CD34⁺ cells in the presence of TPO (100 ng/mL). The supernatant volume corresponding to 10 000 cells was used. Protein levels were expressed as international units per milliliter at the indicated days of culture. Histograms were the mean ± SD of 3 different experiments. Asterisk indicates a significant difference established, using the Student t test (P < .05).