Clonogenic response of CD34⁺ CD38^dim and CD34⁺ CD38⁺ hematopoietic precursors in different cytokine mixtures. CD34⁺ CD38^dim or CD34⁺ CD38⁺ marrow cells (3,000/dish) were plated in methylcellulose containing 1% BSA (Stem Cell Technologies; catalogue no. 4230) supplemented with the indicated cytokines and incubated for 14 days before colonies were counted. Data were pooled from three independent trials. The number of colonies was significantly greater with FL than with the same combination lacking FL: *P < .05; **P < .008. KL stimulated the growth of CD34⁺ CD38^dim cells (P < .02) and CD34⁺ CD38⁺ cells (P < .01) when added to [IL-3 + IL-6].