Post-transplant immune reconstitution after unrelated allogeneic stem cell transplant in patients with acute myeloid leukemia

Abstract

We evaluated immune recovery in 67 patients with acute myeloid leukemia (AML) with a median age of 40 years (4–69) following allo-SCT after reduced (n = 35) or myeloablative (n = 32) conditioning. The following lymphocyte populations were determined on days +30, +90, +180, +270, and +365 by flow associated cell sorting: CD3+, CD3+CD4+, CD3+CD8+, CD3+CD4+/CD3+CD8+ ratio, CD3−CD56+, and CD19+ cells. Peripheral blast count >5% was related to lower number of CD3+CD4+ (day +30) and NK cells (day +180; p = 0.02). Intensity of conditioning did not have any significant impact on the kinetics of immune recovery. Patients with normal CD3+CD4+/CD3+CD8+ ratio (day +30) and NK cell count (day +90; p <0.05) experienced better survival than those with decreased parameters. Post-transplant sepsis/severe infections impaired CD3+CD8+ (day +90; p = 0.015) and CD19+ (day +90; p = 0.02) recovery. Relapse in patients following allo-SCT showed an association with decreased numbers of CD19+ (day +270) and NK cells (day +365). Acute GvHD (II–IV) was accompanied by reduced CD19+ and CD3+CD4+ cells. Thus, the evaluation of post-transplant immune reconstitution in patients with AML might improve risk stratification concerning either relapse or TRM and remains to be further explored.

Keywords:

• Immune reconstitution
• lymphocyte populations
• allogeneic stem cell transplant (allo-SCT)
• acute myeloid leukemia (AML)

Acknowledgements

Ulrike Fritsche-Friedland and Sabine Schwartz provided excellent technical assistance in the department's laboratory; Thomas Hagenström provided assistance with data analysis. The authors would like to thank the staff of the Clinic and Policlinic for Stem Cell Transplantation for the dedicated care of patients.

Declaration of interest: W. Kern is part owner of the Munich Leukemia Laboratory.