MMP-9 gene expression in CD14⁺ cells from healthy donors and patients with MDS. Total RNA was isolated from CD14⁺ cells from 21 healthy donors and 27 MDS patients either immediately (No culture) or after culturing for 5 days in control media or HS5 CM. The inducible levels of MMP-9 gene expression were determined by real-time PCR and normalized with G3PDH gene expression. The induced levels were significantly more variable in monocytes from MDS patients compared to those from healthy donors (P < .001 by Folded F test). The 11 MDS patients with RA are shown in red; the remaining patients are in black. RA patient monocytes analyzed alone also differed significantly from controls (P < .01); all non-RA patient monocytes (including 10 RAEB patients) analyzed as a group differed from controls at P < .001.