A marrow reaction associated with acute-graft-versus-host disease (a-GVHD) has been demonstrated in experimental models; its existence in human transplantation is controversial. The present study aimed to investigate whether clonogenic marrow precursors would be an early marker for a-GVHD and transplant-related mortality (TRM). We prospectively studied 133 patients for colony-forming unit-granulocyte monocyte (CFU-GM) at day +18/+19 post-transplantation. CFU-GM frequency below the
25(th) percentile predicted for acute GVHD score I°-IV° when evaluated in multivariate logistic regression analysis (OR 13.551, CI 1.583-116.031; p=0.01). In the group showing a clonogenic frequency below the 25(th) percentile, the cumulative incidence of GVHD grade II°-IV° was significantly more frequent in respect to the group showing a frequency over the 25(th) percentile, 86% versus 54% (Gray test: p=0.02). In multivariate Cox proportional analysis, a CFU-GM frequency below the 25(th) percentile at day +18, was associated with a reduced overall survival (OS), (HR 1.778, CI 1.022-3.093; p?=?0.04). Patients showing a frequency of CFU-GM <25° percentile had increased TRM in respect to patients showing a clonogenic cell frequency > 25° percentile, (33.5% versus 13.0%, p= 0.01). Patients were divided based on median content of viable CD34+ cells and measurement of viable CD34+ cells was predictive for OS (p=0.005) and TRM (p=0.003). A weak correlation was found between CFU-GM frequency in marrow at day +18 and plasmatic levels of IL2 rec in plasma (r= -0.226, p=0.03). We conclude that marrow progenitor cell counts, on day +18, maybe a useful marker for identifying patients at risk for severe a-GVHD, TRM and inferior Survival.
