Noah Merin, MD, PhD, is a hematologist treating patients with hematologic malignancies, and performs allogeneic stem cell transplantation. Together with the Merchant Lab, Merin has developed a novel haploidentical stem cell transplantation regimen that uses reduced-intensity chemotherapy, post-transplant cyclophosphamide graft-versus-host disease prophylaxis, pre-emptive donor-derived natural killer cell add-back, and omission of drugs that inhibit immune recovery. This approach is reducing rates of graft versus host disease and viral reactivation, and may lead to improved outcomes. Merin is collaborating with the Merchant Lab to study the reconstitution of the immune system following allogeneic stem cell transplantation. Improved stem cell transplant regimens, and greater insight into post-transplant immune reconstitution, will lead to better clinical outcomes for patients undergoing this life-saving procedure. Merin and Merchant are also collaborating on a clinical trial of a bispecific T cell engager, blinatumomab, combined with haploidentical donor lymphocyte infusions, for patients with B-cell acute lymphoblastic leukemia. One goal of this project is to study the spatial clustering of T cells in the bone marrow as a marker of treatment response.