Treatment of Molecular Relapse by Cessation of Immunosuppression After Hematopoietic Stem Cell Transplantation in Pediatric FLT3-ITD AML Monitored by WT1 Expression in Peripheral Blood

Relapse after hematopoietic stem cell transplantation in pediatric acute myeloid leukemia is a fatal event in the majority of cases. Immunotherapy may prevent an impending relapse if instituted at first molecular evidence of disease recurrence. Wilms tumor gene 1 (WT1) is overexpressed in the majority of children and may constitute a useful molecular marker of measurable residual disease applicable for disease monitoring in peripheral blood where the background amplification from healthy hematopoiesis is less prevalent compared with bone marrow. We report the measurable residual disease kinetics from a child with FLT3-internal tandem duplication acute myeloid leukemia where sequential WT1 monitoring in peripheral blood-guided withdrawal of immunosuppression.