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©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Aug 24, 2017; 7(4): 235-242
Published online Aug 24, 2017. doi: 10.5500/wjt.v7.i4.235
Lymphocyte recovery is an independent predictor of relapse in allogeneic hematopoietic cell transplantation recipients for acute leukemia
Moussab Damlaj, Samer Ghazi, Walid Mashaqbeh, Gamal Gmati, Hend Salama, Khadega A Abuelgasim, Mushtaq Rather, Ali Hajeer, Mohsen Al-Zahrani, Abdul-Rahman Jazieh, Ayman Hejazi, Ahmad Al Askar
Moussab Damlaj, Samer Ghazi, Walid Mashaqbeh, Gamal Gmati, Hend Salama, Khadega A Abuelgasim, Mushtaq Rather, Mohsen Al-Zahrani, Abdul-Rahman Jazieh, Ayman Hejazi, Ahmad Al Askar, Division of Hematology and HSCT, Department of Oncology, King Abdulaziz Medical City, Riyadh 11426, Saudi Arabia
Moussab Damlaj, Samer Ghazi, Walid Mashaqbeh, Gamal Gmati, Hend Salama, Khadega A Abuelgasim, Mushtaq Rather, Mohsen Al-Zahrani, Abdul-Rahman Jazieh, Ayman Hejazi, Ahmad Al Askar, King Abdullah International Medical Research Center, Riyadh 11426, Saudi Arabia
Ali Hajeer, King Saud bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia
Author contributions: Damlaj M designed the study; Damlaj M, Ghazi S and Mashaqbeh W collected data; all authors analysed the data, provided patients, wrote and reviewed the manuscript, and approved final version of the manuscript.
Institutional review board statement: This study was approved by the institutional review board at King Abdulaziz Medical City (KAMC) - King Abdallah International Medical Research Center (KAIMRC).
Informed consent statement: The institutional review board waived informed consent due to the retrospective study design without patient contact or intervention; thus representing minimal risk study.
Conflict-of-interest statement: There are no conflicts of interest relevant to the conduct of this study.
Data sharing statement: There are no additional data available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Moussab Damlaj, MD, FRCPC, FACP, Division of Hematology and HSCT, Department of Oncology, King Abdulaziz Medical City, P.O. Box 22490, Riyadh 11426, Saudi Arabia.
damlajmo@ngha.med.sa
Fax: +966-11-8011111
Received: February 11, 2017
Peer-review started: February 15, 2017
First decision: March 27, 2017
Revised: July 6, 2017
Accepted: July 21, 2017
Article in press: July 24, 2017
Published online: August 24, 2017
Processing time: 191 Days and 14.8 Hours
AIM
To examine the optimal absolute lymphocyte count (ALC) cut-off utilizing receiver operator characteristics (ROC) in addition to graft characteristics associated with early ALC recovery.
METHODS
Patients who received T-cell replete peripheral hematopoietic cell transplantation (HCT) for acute leukemia were identified. ALC cut-off was established using ROC analysis and subsequently the cohort was stratified. Time to endpoint analysis and cox regression modelling was computed to analyze outcomes.
RESULTS
A total of 72 patients met the inclusion criteria and were analyzed. Optimal ALC cut-off was established to be on day 14 (D14) with ALC > 0.3 × 109/L. At 2 years, cumulative incidence of relapse was 16.9% vs 46.9% (P = 0.025) for early and delayed lymphocyte recovery cohorts, respectively. Chronic graft vs host disease was more prevalent in the early lymphocyte recovery (ELR) group at 70% vs 27%, respectively (P = 0.0006). On multivariable analysis for relapse, ELR retained its prognostic significance with HR = 0.27 (0.05-0.94, P = 0.038).
CONCLUSION
ELR is an independent predictor for relapse in patients receiving allogeneic HCT for acute leukemia. ELR was influenced by graft characteristics particularly CD34 count.
Core tip: Disease relapse remains the most common cause of treatment failure after allogeneic hematopoietic stem cell transplantation for acute leukemia. Previous studies have identified that early lymphocyte recovery can be a surrogate of graft vs leukemia effect hence identifying high risk patients for relapse. However, published reports are heterogeneous with regards to timeline and magnitude of lymphocyte recovery. Using receiver operator characteristics with area under the curve, we identified that absolute lymphocyte count > 0.3 × 109/L at day 14 is associated with half the relapse risk which was statistically significant at the multivariable analysis. There was a trend towards improved progression free survival and overall survival for patients with early lymphocyte recovery. In conclusion, we observed that lymphocyte recovery is an independent predictor of relapse in allogeneic transplant recipients for acute leukemia. This would help identify high risk patients who may benefit from maintenance strategies post-transplant.
