PB2322 SPLEEN SIZE AS CLINICAL RISK FACTOR FOR GRAFT FAILURE FOLLOWING ALLOGENEIC STEM CELL TRANSPLANTATION IN ACUTE LEUKEMIA PATIENTS
Authors: M. Drokov, U. Maslikova, L. Kuzmina, G. Yatsyk, V. Vasilieva, E. Mikhalcova, N. Popova, O. Pyrikova, A. Kireeva, O. Koroleva, M. Nareyko, D. Dubnyak, Z. Konova, E. Usikova, A. Dmitrova, O. Starikova, E. Parovichnikova, V. Savchenko
Journal: HemaSphere (2019)

Background: Primary and secondary graft failure (GF) following allogeneic hematopoietic stem cell transplantation (allo‐HSCT) leads to prolonged neutropenia, infection complications and as a consequence lowered overall survival. Bone marrow as a graft source, HLA‐mismatched donor is a main factors which can influence GF in acute leukemia patients (pts) during first six months after allo‐HSCT. Nevertheless not all GF episodes can be explained by this factors. Here we report data about influence of spleen size (length width) assessed by transabdominal ultrasound on graft failure in first 6 months in acute leukemia patients in CR who underwent allo‐HSCT. Aims: Identify risk factors for GF in patients with acute leukemia remission. Methods: We analyzed medical records of 143 pts with acute leukemia (AML n = 100 (69.9%), ALL n = 43 (30.1%)) who underwent allo‐HSCT between 2013 and 2018 at National Research Center for Hematology and was alive for more than 28 days after allo‐HSCT. A median age of patients was 34 (19‐66) years, 66 (46.2%) males and 77 (53.8%) females. At the time of transplantation 124 (86.7%) pts were in complete remission and 19 (13.3%) pts had advanced disease. Most pts (n = 112; 78.3%) received reduced intensity conditioning regimen (RIC) and 31pts (21.7%) underwent myeloablative conditioning (MAC). Donors were: HLA‐matched unrelated (MRD) – 43.4% (n = 62); mismatched unrelated donor (MMUD) 27.3% (n = 39); matched related donor (MRD) ‐25.9% (n = 37); haploidentical (excluding TCR ab‐depletion) – 3.4% (n = 5), Bone marrow (BM) was used as a graft source in 60.1% (86 pts) and peripheral blood stem cell (PBSC) ‐ in 39.9% (57 pts). Spleen size was routinely evaluated before allo‐HSCT using transabdominal sonography. Cox Proportional‐Hazards model was used to identify influence of spleen size (≥3600 mm 2 vs &lt;3600 mm 2 ) as independent prognostic factor (conditioning regimen, donor type, graft source, HLA‐disparity were also entered as covariates as well known risk factors for GF). Results: Results of Cox Proportional‐Hazards model are shown on Figure 1. According to our data spleen size (length width) ≥3600 mm 2 assessed by transabdominal sonography before allo‐HSCT was associated with high risk of GF within six months of follow up period after allo‐HSCT. HR‐3.67 (95% Cl, 1.05‐12.74, p = 0.04). Figure 1 . Results of Cox Proportional‐Hazards model Summary/Conclusion: HLA‐disparity, BM as a graft source is characterized by increased probability of GF. In addition we identify that spleen size ≥3600 mm 2 assessed by transabdominal sonography before allo‐HSCT also increased GF (up to 3.67 times). Due to that fact it's not recommended to use BM as a graft source for acute leukemia patients who underwent allo‐HSCT especially from MMUD. image