Abstract 2536: Post-transplantation NK cell is a useful predictor of graft-versus-host-disease in allogeneic hematopoietic stem cell transplantation
Authors: Kim Seo Yeon , Lee Hyewon , Shim Hyoeun , Eom Hyeon-Seok , Kong Sun-Young 
Published: May 2015

Abstract
Background: Reconstitution of the immune system following allogeneic hematopoietic stem cell transplantation (HSCT) is important for transplantation outcome. Quantitative measurement of the lymphocyte subset (LST) by flow cytometry has been used for analysis of the immune system. However, the association of each lymphocyte subset with transplantation has not been fully elucidated. Here, we investigated the relevance of each lymphocyte fraction as a predictor for HSCT outcome. Methods: A total of 70 patients who received allogeneic HSCT at national cancer center were included. The median age was 42 years (range 20-64) with 34 males (49%). The enrolled diseases included acute myeloid leukemia (n=33, 47%), acute lymphoblastic leukemia (n=13, 19%), myeloid dysplastic syndrome (n=9, 13%), non-hodgkin lymphoma (n=5, 7%), severe aplastic anemia (n=4, 6%), chronic myeloid leukemia (n=3, 4%), and multiple myeloma (n=3, 4%). LST measurements for CD3, CD4, CD8, CD19, and CD16/CD56-positive cells were performed at 7 days before and 30 days after HSCT. The absolute counts of lymphocyte subsets were evaluated for acute graft-versus-host disease (GVHD), infection (bacterial, viral, and fungal) and complications during 100 days post HSCT. GVHD was pathologically validated and determination of infection was based on microbiology results including culture, cytomegalovirus antigenemia and virus PCR. Moreover, the association between LST and treatment failure as relapse or death during any period was analyzed. Results: The number of each fraction of lymphocyte subsets at 7 days before and 30 days after HSCT were as following (mean ± SD/uL): CD3 (804.5 ± 564.6, 862.1 ±890.0, p =0.719), CD4 (339.74 ± 284.8, 223.5 ± 189.9, p =0.009, CD8 (430.6 ± 362.9, 576.9 ± 703.1, p = 0.169, CD19 (39.7 ± 72.3, 19.1 ± 22.9, p =0.035), NK (86.6 ± 86.8, 272.5 ± 192.2, p &lt; 0.001). Each lymphocyte fraction does not show any association with complications and increased risk for infection. However, the decreased number of NK cells at 30 days after HSCT represented association with an increased risk of GVHD (n=21) (GVHD group vs. non-GVHD group: 206.4±195.2 vs. 310.1 ± 182.5, p = 0.033). When the NK cell level was divided as median value (219/µL), the group of lower level has correlation decreased overall survival (p = 0.018). Moreover, decreased number of NK cells at 90 days after HSCT was also associated with an increased risk of GVHD (145.3±107.9 vs. 370.2±265.8, p = 0.043). Conclusion: These results suggest that measuring the early recovery of NK cells at 30 days and analyzing the trend of LST can be a useful predictor of clinical outcome including GVHD in allogeneic HSCT.
Citation Format: Seo Yeon Kim, Hyewon Lee, Hyoeun Shim, Hyeon-Seok Eom, Sun-Young Kong. Post-transplantation NK cell is a useful predictor of graft-versus-host-disease in allogeneic hematopoietic stem cell transplantation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2536. doi:10.1158/1538-7445.AM2014-2536