Differentiation of CD41a⁺CD42a⁻ cells in the presence of 6 cytokines.

CD34⁺ cells from a TAR syndrome patient and a control were grown in the presence of SCF plus PEG-rHuMGDF for 8 days. CD41a⁺CD42a^- cells were sorted and cultured for 10 additional days in the presence of 6 cytokines (SCF, IL-3, IL-6, G-CSF, PEG-rHuMGDF, and Epo). At the end of the culture, cells were restained with an R-PE anti-CD41a MoAb and an anti-CD42a MoAb. The TAR syndrome patient cells remained CD41a⁺ and did not acquire CD42a or new markers of differentiation. The majority of normal CD41a⁺CD42a^- cells lost the CD41 antigen and acquired other markers of differentiation, in particular, glycophorin A (data not shown), and the remaining differentiated along the MK pathway with the appearance of CD42.