Gvhd-Associated Early Impairment of Marrow Function Is Frequent after Allogeneic Transplantation and Is a Sensitive Biomarker for Prediction of Treatment Related Mortality and of Overall Survival

INTRODUCTION: Aim of our study was to determine the role of acute-GVHD in influencing early marrow function and whether assessment of “GVHD-associated marrow impairment” may predict transplant outcome.

METHODS: We have prospectively studied 62 patients who received T-replete allogeneic stem cell transplantation because of various malignancies. At day +18/+19, we determined in bone marrow: CD34+ cells, frequency of clonogenic cell (CFU-GM and BFU-E) and, in 20 patients, also CD34+ cells showing apoptosis (AnnexinV/7-AAD). Results were related to acute-GVHD and to clinical outcome in terms of Treatment Related Mortality (TRM), Relapse Rate (RR) and Overall Survival (OS). To distinguish the effect of a-GVHD from that determined by corticosteroid, patients were divided in three groups according to time of presentation of a-GVHD: “Early a-GVHD, “No a-GVHD” and “Impending a-GVHD”. The latter group consisted of patients presenting a-GVHD after engraftment.

RESULTS: In univariate analysis “Febrile neutropenia” and” Acute GVHD” were important factors for a reduction of frequency of marrow clonogenic cells assessed on day +18/+19. However, in multivariate analysis only “Acute GVHD” was able to influence frequency of marrow CFU-GM and BFU-E at day +18/+19. Patients not developing “a-GVHD” until day +90, had on day+18 a median growth of CFU-GM of 202/10e5 plated cells while patients suffering “early GVHD” had a marrow CFU-GM growth significantly reduced: 82/10e5 plated cells, (p= 0.0009). Median CFU-GM was found significantly reduced also in patients defined as “impending GVHD” (onset of a-GVHD at day +20-/+90) (p=0.01). Apoptotic CD34+ cells in marrow cells at day +18/+19 were inversely correlated to frequency of marrow BFU-E (r= -0.5, p=0.04). Taking into account competing risks, Cumulative Incidence of TRM at 2 y in the group of patients having a frequency of marrow CFU-GM over median was 5% while it was 30% in the group having CFU-GM below the median (log-rank: p=0.004). Cumulative incidence of Relapse was not significantly different in these two groups (31% versus 34%). OS was significantly better in group having CFU-GM over median: 62% versus 35% (logrank: p=0.02). Frequency of CFU-GM over median at day +18/+19 was a factor important for a reduced risk of death (HR=0.358; p=0.004) also after adjusting, using multivariate Cox analysis, for Disease Status (Early versus Advanced).

CONCLUSIONS: acute-GVHD impairs early and significantly marrow function, marrow-GVHD is a sensitive biomarker for prediction of TRM and OS.