[Clinical study of haploidentical hematopoietic stem cell transplantation on 15 cases of adult-onset primary hemophagocytic lymphohistiocytosis].

This study was designed to evaluate the efficacy of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for adult-onset primary hemophagocytic lymphohistiocytosis (HLH) . A retrospective study was carried out to analyze the clinical data of 15 adult patients with primary HLH who received haplo-HSCT from January 2013 to October 2019 in Beijing Friendship Hospital, Capital Medical University, Beijing, China. Among the 15 patients included in the study, ten were males and five were females, with a median age of 21 years old (18-52) . Eight of the patients had familial hemophagocytic lymphohistiocytosis type 2 (FHL-2) , four had FHL-3, one had Griscelli syndrome type 2 (GS-2) , one had X-linked lymphoproliferative disease type 1 (XLP-1) , and the other had XLP-2. The median time from HLH diagnosis to transplantation was 7 months (2-46 months) . Seven patients were treated with Bu/Cy condition regimen prior to transplantation. Meanwhile, the other eight cases were treated with TBI/Cy. The median concentration of mononuclear cell (MNC) infusion was 12.6 (9.2-20.3) ×10(8)/kg and CD34(+) cells was 4.91 (2.51-8.37) ×10(6)/kg. The median time of leukocyte engraftment was on day 13 following transplantation (10-23 days) , and the platelet engraftment was on day 12 (9-36) . Graft failure (GF) finally occurred in two patients (one primary GF and one secondary GF) . The cumulative incidence of acute graft-versus-host-disease (GVHD) grades 2 to 4 was 71.4% (10/14) and chronic GVHD was 30.8% (4/13) , respectively. The five-year overall survival (OS) for all 15 cases of primary HLH was 65.5% (95% , 34.9%-73.3%) and the transplant-related mortality (TRM) was 26.7% (4/15) . The five-year OS was 87.5% (95% , 38.7%-66.3%) in eight patients who received haplo-HSCT subsequent to initial therapy and 42.9% (95% , 8.5%-65.2%) in patients seven patients who needed salvage therapy prior to haplo-HSCT ((2)=2.387, =0.122) . The five-year OS was 85.7% (95% , 50.4%-89.8%) in eight patients who achieved complete response before haplo-HSCT and 42.9% (95% , 6.4%-53.0%) in seven patients with partial response ((2)=3.185, =0.074) . The results indicated that haplo-HSCT is a promising method for the treatment of primary HLH in adults.