# Modified Prophylactic Donor Lymphocyte Infusion (DLI) in an Adult T Cell Lymphoma/Leukemia (ATLL) Patient—Modality of Relapse Prevention

## TL;DR

A modified donor lymphocyte infusion after stem cell transplant helped prevent relapse in an ATLL patient without causing severe side effects.

## Contribution

The study presents a modified prophylactic DLI regimen that shows potential for preventing ATLL relapse without significant GVHD.

## Key findings

- The patient remained in remission for 40 months after modified prophylactic DLI.
- No significant graft-versus-host disease was observed with the modified DLI regimen.
- The approach suggests a balance between efficacy and safety in ATLL relapse prevention.

## Abstract

Adult T-cell Leukemia/Lymphoma (ATLL) is a rare but aggressive malignancy associated with the human T-cell lymphotropic virus type 1 (HTLV-1). ATLL is a challenging malignancy characterized by its aggressive nature and poor prognosis. Despite advancements in treatment, relapse rates remain high. Donor lymphocyte infusion (DLI) is a promising therapeutic option post-hematopoietic stem cell transplantation (HSCT) to prevent relapse. However, the prophylactic use of DLI in ATLL patients remains underexplored. We report the case of a 45-year-old female diagnosed with ATLL. Following induction chemotherapy and successful HSCT, a modified prophylactic DLI regimen was administered, consisting of gradually increasing doses of donor lymphocytes. The patient demonstrated a favorable response with no significant graft-versus-host disease (GVHD) and maintained remission over a 40-month follow-up period, suggesting a potential benefit of this approach. This case highlights the potential efficacy and safety of modified prophylactic DLI in ATLL patients, warranting further investigation. Our findings suggest that modified prophylactic DLI is a viable option for ATLL patients post-HSCT, offering a balance between efficacy and safety. Future research should focus on optimizing DLI protocols and exploring biomarkers for response prediction.