Mixed Chimerism and Clinical Outcome of Hematopoietic Stem Cell Transplantation in Glanzmann Thrombasthenia: Experience on 2 Siblings and Literature Review.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive platelet disorder characterized by abnormalities in platelet aggregation, resulting from quantitative or qualitative defects in integrins αIIb and β3. Currently, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only potentially curative therapeutic approach for severe GT. In this report, we present 2 children with GT that underwent successful allo-HSCT, along with 2008 to 2022 data from the Center for International Blood and Marrow Transplant Research and a summary of the existing literature providing further evidence that allo-HSCT can be a curative approach that prevents severe and life-threatening bleeding in GT. Our cases empathize the importance of monitoring flow cytometric platelet integrin αIIb (GPIIb) and β3 (GPIIIa) detection in identifying potential late graft rejection, which is a more direct assessment of platelet populations, particularly in the case of pretransplant presence of platelet antiglycoprotein GPIIb/IIIa complex antibodies.