Relapse rates have been shown to be higher and survival rates lower in patients with acute myeloid leukemia (AML) who are MRD positive prior to allogeneic stem cell transplantation (SCT), when compared with patients who are MRD negative. A study published in October in Transplantation and Cellular Therapy suggests that enhanced reconstitution of γ δ T cells post-transplant may overcome this higher relapse risk and improve survival in MRD-positive patients.

The retrospective study included 202 patients (median age 58, 57% male) with AML in complete remission before allogeneic SCT, of whom 100 were MRD positive at a sensitivity of 10^-4 to 10^-5 on flow cytometry performed within a median of 7 days prior to transplantation. Median follow-up of survivors was 28 months.

In multivariable analysis, both leukemia-free survival and overall survival were significantly improved in MRD-positive patients with an above-median level of γ δ T cells on days +30 and +100. A higher level of γ δ T cells on day +30 was associated with a significantly reduced risk of relapse.   

“In contrast, we found no significant impact of γ δ T cell level on post-transplantation outcomes for MRD-negative patients, suggesting that improved reconstitution of γ δ T cell levels after allo SCT may overcome the negative impact in MRD-positive AML patients,” wrote senior author Nicolaus Kröger of the University of Hamburg in Germany and his coauthors.

• Klyuchnikov E, Badbaran A, Massoud R, et al. Enhanced Immune Reconstitution of γδ T Cells after Allogeneic Stem Cell Transplantation Overcomes the Negative Impact of Pretransplantation Minimal Residual Disease-Positive Status in Patients with Acute Myelogenous Leukemia. Transplant Cell Ther. 2021;27(10):841-850. doi:10.1016/j.jtct.2021.06.003

Tags: MRD, BMT, transplantation, Relapse, Survival, post-transplant, relapse rates, reconstitution, reduce risk