Immune reconstitution Infused peripheral blood autograft absolute lymphocyte count correlates with day 15 absolute lymphocyte count and clinical outcome after autologous peripheral hematopoietic stem cell transplantation in non- Hodgkin’s lymphoma LF Porrata 1 , MR Litzow 1 , DJ Inwards 1 , DA Gastineau 1,2 , SB Moore 2 , AA Pineda 2 , KL Bundy 2 , DJ Padley 2 , D Persky 3 , SM Ansell 1 , INM Micallef 1 and SN Markovic 1 1 Division of Hematology, Department of Internal Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA; 2 Division of Transfusion Medicine, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA; and 3 Department of Internal Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905,USA Summary: Absolute lymphocyte count at day 15 (ALC-15) after autologous peripheral blood hematopoietic stem cell transplantation (APHSCT) is an independent prognostic factor for survival in non-Hodgkin’s lymphoma (NHL). Factors affecting ALC-15 remain unknown. We hypothe- sized that dose of infused autograft lymphocytes (A-ALC) directly impacts upon ALC-15. A total of 190 consecutive NHL patients received A-ALC between 1993 and 2001. The primary end point was correlation between A-ALC and ALC-15. A strong correlation was identified (r ¼ 0.71). A higher A-ALC was infused into patients achieving an ALC-15 X500/ll vs ALC-15 o500/ll (median of 0.68  10 9 /kg (0.04–2.21  10 9 /kg), vs 0.34  10 9 /kg (0.04–1.42  10 9 /kg), Po0.0001). The median follow-up for all patients was 36 months (max- imum of 109 months). The A-ALC threshold was determined at 0.5  10 9 /kg. The median overall survival (OS) and progression-free survival (PFS) times were longer in patients who received an A-ALC X0.5  10 9 /kg vs A-ALC o0.5  10 9 /kg (76 vs 17 months, Po0.0001; 49 vs 10 months, Po0.0001, respectively). Multivariate analysis demonstrated A-ALC to be an independent prognostic indicator for OS and PFS. These data support our hypothesis that ALC-15 and survival are dependent upon the dose of infused A-ALC in NHL. Bone Marrow Transplantation (2004) 33, 291–298. doi:10.1038/sj.bmt.1704355 Published online 15 December 2003 Keywords: infused peripheral blood autograft absolute lymphocyte count; absolute lymphocyte recovery; auto- logous peripheral blood hematopoietic stem cell transplan- tation The absolute lymphocyte count (ALC) recovery of 500 cells/ml or more at day 15 (ALC-15) after autologous peripheral blood hematopoietic stem cell transplantation (APHSCT) has been reported as a powerful, independent prognostic indicator of clinical outcomes for patients with acute myelogenous leukemia, 1 breast cancer, 2,3 Hodgkin’s lymphoma, 4,5 non-Hodgkin’s lymphoma, 6–8 multiple mye- loma, 6–8 and ovarian cancer. 9–10 However, factors affecting ALC-15 recovery have not been identified. In this study, we evaluated the hypothesis that ALC-15 is directly dependent upon the dose of infused lymphocytes in the peripheral blood autograft (A-ALC) in patients with non-Hodgkin’s lymphoma. Patients, materials, and methods Patient population Only patients who received autologous peripheral blood stem cell transplants for non-Hodgkin’s lymphoma (NHL) were included in the study. Patients who received bone marrow (BM) harvests or the combination of APHSCT and BM harvests were excluded. Between 1987 and 2001, a total of 303 autologous transplants were performed in the Mayo Clinic for patients with NHL. In all, 47 transplanted before 1993 were excluded because they received only BM harvest as their stem cell source. Of the 256 patients transplanted from 1993 to 2001, 190 patients (74%) received only APHSCT and were included in this study. The rest of the patients received either BM harvest or a combination of autologous peripheral blood stem cells and BM stem cells. Data from our previous publication 6 of 53 patients who received only autologous peripheral blood stem cells were also included in the analysis of this study. This is a retrospective study where data have been prospectively collected over time and entered into a computerized database. Response to therapy, relapse, and survival data are updated continuously. No patients were lost to follow-up. All patients gave written, informed consent allowing the use of their medical records for Received 23 April 2003; accepted 05 July 2003 Published online 15 December 2003 Correspondence: Dr SN Markovic, Department of Hematology and Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA; E-mail: markovic.svetomir@mayo.edu Bone Marrow Transplantation (2004) 33, 291–298 & 2004 Nature Publishing Group All rights reserved 0268-3369/04 $25.00 www.nature.com/bmt