Hematopoietic stem cell transplantation with TCRαβ+/CD19+ - graft depletion for hemophagocytic lymphohistiocytosis

The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. We present the outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) with TCRab+/CD19+ graft depletion in patients with genetic hemophagocytic lymphohistiocytosis (HLH) at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology from 2012 to 2019. Thirty-six patients with various HLH: familial HLH (n = 20), X-linked lymphoproliferative disease (XLP) type 1 (n = 4), XLP type 2 (n = 9), Griscelli syndrome (n = 1), Chediak–Higashi syndrome (n = 2) received HSCT. Conditioning regimens were based on treosulfan in 9 patients, or on two alkylating agents: treosulfan with either melphalan, or thiotepa in 27 patients; all 36 patients received fludarabine and serotherapy. Thirty-two patients received rituximab 100 mg/m2 the day before stem cell infusion. Post- HSCT “graft versus host” disease (GvHD) prophylaxis was used in 29 patients. As a graft source peripheral blood stem cells from matched unrelated (n = 23), matched related (n = 3) and haploidentical family (n = 10) donors after TCRαβ⁺/CD19⁺ graft depletion were used. The cumulative incidence of primary and secondary graft failure in all patients was 0.11 (95% CI 0.04–0.29). The incidence of acute GvHD was limited to stage I-II. Overall survival was 0.91 (95% CI 0.82–1) without any significant differences in various donor groups (p = 0.33) as well as different conditioning regimens (p = 0.75). Allogeneic HSCT with TCRαβ⁺/CD19⁺ graft depletion after treosulfan-based conditioning is effective and safe technology for patients with genetic HLH.