Pierre-Simon Rohrlich

Allogenic hematopoietic stem cell transplantation (allo-HSCT) offers a curative option for pediatric patients with high-risk hematological malignancies. However, donor availability remains a challenge. Haploidentical (haplo)-HSCT provides nearly universal donor availability, readily access to the graft, and opportunity for post-transplant cell therapy. The developpement of post-transplant cyclophosphamide (PTCy) has helped overcome bidirectional allorecactivity [1,2,3].

Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare [1] but severe complication of hematopoietic stem cell transplantation (HSCT), with a letality of 90% without specific treatment. Several triggering factors have been identified (HLA-mismatch, conditioning regimens, immunosuppressive agents, GVHD or viral infections) [2]; recently, the role of uncontrolled complement alternative pathway (CAP) activation after endothelial injury also raised interest.