Lymphocyte recovery on day 100 after allogeneic hematopoietic stem cell transplant predicts non-relapse mortality in patients with acute leukemia or myelodysplastic syndrome.

Abstract To clarify the clinical significance of lymphocyte recovery on day 100 after allogeneic hematopoietic stem cell transplant (allo-HSCT), we retrospectively studied 157 patients with hematologic malignancies who underwent allo-HSCT. An absolute lymphocyte count < 500/μL was defined as lymphocytopenia. There was a significant relationship between lymphocytopenia and advanced disease at allo-HSCT or corticosteroid administration within 100 days. Lymphocytopenia on day 100 (hazard ratio [HR]: 2.4; 95% confidence interval [CI]: 1.3-4.5; p = 0.006) and advanced disease at allo-HSCT (HR: 2.2; 95% CI: 1.3-3.9; p = 0.005) were prognostic factors for overall survival by multivariate analysis. Advanced disease was significantly associated with relapse (HR: 2.8; 95% CI: 1.5-5.4; p = 0.002), while lymphocytopenia was an independent predictor of non-relapse mortality (HR: 2.8; 95% CI: 1.1-6.8; p = 0.027). These results suggest that lymphocyte recovery on day 100 may be an important predictor of late complications in patients receiving allo-HSCT for hematologic malignancies.