Impact of marrow cytogenetics and morphology on in vitro hematopoiesis in the myelodysplastic syndromes: Comparison between recombinant human granulocyte colony-stimulating factor (CSF) and granulocyte-monocyte CSF

Marrow cells from 36 patients with myelodysplastic syndromes (MDS) (13 refractory anemia [RA], 14 refractory anemia with excess of blasts [RAEB], 9 RAEB in transformation [RAEB-T]) were evaluated for their in vitro proliferative and differentiative responsiveness to recombinant human granulocyte colony-stimulating factor (G-CSF) or granulocyte-monocyte CSF (GM-CSF). GM-CSF exerted a stronger proliferative stimulus than G-CSF for marrow myeloid clonal growth (CFU-GM) in these patients (44 v 12 colonies per 10⁵ nonadherent buoyant bone marrow cells [NAB], respectively, P < .025). GM-CSF stimulated increased CFU-GM growth in the 16 patients with abnormal marrow cytogenetics in comparison with the 20 patients who had normal cytogenetics (52 and 30 colonies per 10⁵ NAB, respectively. P < .05), whereas no such difference could be demonstrated with G-CSF (11 and 16 colonies per 10⁵ NAB. respectively). In contrast, granulocytic differentiation of marrow cells was induced in liquid culture by G-CSF in 15 of 32 (47% patients), while GM-CSF did so in only 4 of 18 (22%) patients (P < .025) including, for RAEB/RAEB-T patients: 9 of 18 versus O of 9, respectively (P < .025). For MDS patients with normal cytogenetics, G-CSF- and GM-CSF-induced marrow cell granulocytic differentiation in 12 of 18 (67%) versus 3 of 11 (27%), respectively (P < .025), contrasted with granulocytic induction in only 3 of 14 (21%) and 1 of 7 (14%) patients with abnormal cytogenetics, respectively. We conclude that G-CSF has greater granulocytic differentiative and less proliferative activity for MDS marrow cells than GM-CSF in vitro, particularly for RAEB/RAEB-T patients and those with normal cytogenetics.