Absolute lymphocyte count (ALC) recovery ≥500 cells/mL at day 15 or 30 post-autologous (autoBMT) transplantation has been reported in many studies as an independent prognostic indicator of overall survival (OS) and progression free survival (PFS) in non-Hodgkin lymphoma (NHL), Hodgkin Disease (HD), multiple myeloma (MM) and breast cancer patients. ALC recovery has also been reported in the allogeneic blood and marrow transplant (alloBMT) setting as an important factor in predicting risk of relapse of acute lymphocytic leukemia (ALL) and acute myelogenous leukemia (AML). It has been shown in previous reports that donor age is critically important for OS after alloBMT. In addition, increased donor age correlates with a reduction of common lymphoid progenitor (CLP) differentiation potential which led us to hypothesize that donor age might predict ALC recovery time in related and unrelated alloBMT recipients. We reviewed 76 related and 36 unrelated HLA-matched consecutive patients with hematological malignancies who underwent first alloBMT at Roswell Park Cancer Institute between 4/20/2000 and 3/17/2006. The patient population included 53 males and 59 females with a median (range) age of 44 (4–68) years. Conditioning regimens were FluMel (n=33), CyTBI (n=32), BuCy (n=19), FluCy (n=13), VCT (n=11), and other (n=4). The stem cell source was bone marrow (n=34), peripheral blood (n=77) or both (n=1). Hematologic engraftment was defined as absolute neutrophil count (ANC) reaching 500 cells/ml or more for 3 consecutive days. ALC at day 30 and time to ALC ≥ 500 cells/mL were analyzed. Our results show that peripheral blood (p=0.04) and a higher CD34+ dose (p=0.05) were significantly associated with day 30 ALC ≥ 500. Time to ALC recovery ≥500 cells/mL was not significantly related to donor age for related alloBMT (p=0.340). However, in unrelated alloBMT patients, there was a trend toward increasing donor age associated with a longer time to ALC recovery ≥ 500 cells/mL (p=0.087). ANC recovery correlates with ALC recovery in related (R=0.237, p=0.02) and unrelated (R=0.514, p<0.001) alloBMT recipients. Recipient and donor age were strongly correlated in related alloBMT patients (R=0.89, p<0.001) and weakly correlated in unrelated alloBMT patients (R=0.236, p=0.09). ALC recovery ≥ 500 at day 30 post alloBMT was not a significant predictor of OS in either the related or unrelated subgroups. We will further examine donor-recipient age disparities in unrelated alloBMT patients and present multivariate analyses of predictors for time to ALC recovery.

Disclosure: No relevant conflicts of interest to declare.

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