Leukemia (2002) 16, 1311–1318  2002 Nature Publishing Group All rights reserved 0887-6924/02 $25.00 www.nature.com/leu Early lymphocyte recovery is a predictive factor for prolonged survival after autologous hematopoietic stem cell transplantation for acute myelogenous leukemia LF Porrata 1 , MR Litzow 1 , A Tefferi 1 , L Letendre 1 , S Kumar 1 , SM Geyer 2 and SN Markovic 1,3 1 Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA; 2 Cancer Center Statistics, Section of Biostatistics, Mayo Clinic, Rochester, MN, USA; and 3 Division of Hematology, Department of Internal Medicine, and Division of Medical Oncology, Department of Oncology, Mayo Clinic, Rochester, MN, USA Absolute lymphocyte count (ALC) recovery correlates with sur- vival after autologous hematopoietic stem cell transplantation (AHSCT) for patients with multiple myeloma, non-Hodgkin’s lymphoma, and metastatic breast cancer. The role of ALC recovery in relationship to clinical outcome after AHSCT in patients with acute myelogenous leukemia is unknown. We analyzed 45 patients who underwent AHSCT at Mayo Clinic, Rochester, Minnesota between 1990 and 2000. The ALC thres- hold was selected at 500 cells/l on day 15 post-AHSCT based on our previous studies. Thirty-two females and 13 males were included in the study with a median age of 45 years (range 12– 75). The median follow-up was 14 months with a maximum of 129 months. The median overall and leukemia-free survival were significantly better for the 23 patients with ALC at day 15 500 cells/l compared with 22 patients with ALC 500 cells/l (not yet reached vs 10 months, P  0.0009; 105 vs 9 months, P  0.0008, respectively). In conclusion, ALC 500 cells/l on day 15 post-AHSCT is associated with better survival in acute myelogenous leukemia and requires further studies. Leukemia (2002) 16, 1311–1318. doi:10.1038/sj.leu.2402503 Keywords: acute myelogenous leukemia; absolute lymphocyte count; autologous hematopoietic stem cell transplantation Introduction Absolute lymphocyte count (ALC) correlates with survival in allogeneic stem cell transplantation. 1,2 We have recently reported a correlation between ALC recovery on day 15 post- autologous hematopoietic stem cell transplantation (AHSCT) and prolonged survival in patients with multiple myeloma (MM), 3 non-Hodgkin’s lymphoma (NHL), 3 and metastatic bre- ast cancer. 4 ALC is a powerful, independent prognostic factor for overall survival (OS) and progression-free survival (PFS) in patients with MM and NHL. To assess whether ALC recovery is associated with survival in patients with acute myelogenous leukemia (AML) post-AHSCT, we analyzed ALC recovery on day 15 post-AHSCT in AML. Materials and methods Patient population Forty-five consecutive patients underwent AHSCT for AML at Mayo Clinic Rochester, MN, between January 1990 and December 2000. One patient had two autologous hematopo- ietic stem cell transplantations. Data were only used from the first transplant for this patient in the study. Data from trans- plant recipients were collected prospectively and entered into a computerized database. Response to therapy, relapse, and Correspondence: SN Markovic, Division of Hematology, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; Fax: 507–266–4972 Received 24 April 2001; accepted 4 December 2001 survival data were updated continuously. No patients were lost to follow-up. All patients gave written, informed consent allowing utilization of their medical records for medical research. Approval for the retrospective review of these rec- ords was obtained from the Mayo Clinic Institutional Review Board and was in accordance with US federal regulations and the Declaration of Helsinki. Eligibility criteria The eligibility criteria for patients to undergo AHSCT included adequate hepatic, pulmonary, cardiac and renal function; ECOG performance status of 0, 1, or 2; and no active infec- tion. Patients were excluded if they did not meet the eligibility criteria or had any other concomitant illness that would preclude AHSCT. Prognostic factors The prognostic factors used were selected from multiple publi- cations 5–8 which have identified various prognostic factors for AML at diagnosis, pre-transplantation and post-transplan- tation. The prognostic factors at diagnosis included: cytog- enetic abnormalities (favorable, intermediate, unfavorable), French–American–British (FAB) classification (M3 vs other), gender, and white blood cell (WBC) count (10.5 × 10 9 /l). The prognostic factors before transplantation included: age (45 years old), clinical status (complete remission, partial remission, or relapse untreated), complete remission (CR) status alone, the number of consolidation regimens after achieving CR, duration of complete remission after induction chemotherapy (12 months), interval from CR1 or CR2 to transplantation (4 months), and performance status prior to transplantation (ECOG 1). The prognostic factors after trans- plantation included: ALC at day 15 post-AHSCT, absolute neutrophil count (ANC) at day 15 post-AHSCT, conditioning regimens (total body irradiation (TBI) + chemotherapy vs chemotherapy alone), growth factor (G-CSF vs GM-CSF), plat- elet count at day 15 post-AHSCT and stem cell source (bone marrow vs peripheral blood). Favorable cytogenetic abnor- malities included t(8;12), t(15;17) and inv(16)/t(16;16). Cyto- genetic abnormalities of intermediate prognosis included normal karyotype and missing Y chromosome; all others as well as complex chromosomal changes were classified as unfavorable. 6 Conditioning regimens The conditioning regimens included: cyclophosphamide (60 mg/m 2 on days -5, -4) and TBI (220 rads, twice a day on days -3, -2 and -1; 1320 cGy total dose) 33 patients; busulfan