Common myeloid progenitors (CMPs) and granulocyte-monocyte progenitors (GMPs) were sorted from bone marrow of HDs and WHIM-09 and were tested in triplicate in a colony-formation assay in vitro. Burst forming unit-erythroid (BFU-E), granulocyte monocyte colony-forming unit (GM-CFU) and granulocyte, erythrocyte, monocyte, megakaryocyte colony-forming unit (GEMM-CFU) colonies generated from 2000 CMP cells (A) or 1000 GMP cells (B) were counted after 14 days in culture. Data were combined from two experiments and plotted and summarized as the mean ± SEM. Each HD was tested once, but the total for the two experiments was 6 (A) and 9 (B). WHIM-09 was tested in both experiments, and all individuals tested were tested in replicate determinations. A, *p<0.05, two-tailed unpaired parametric t-test. B, ** p<0.01, two-tailed unpaired parametric t-test.