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

Objective: This study was designed to evaluate the efficacy of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) for adult-onset primary hemophagocytic lymphohistiocytosis (HLH) . Method: 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. Results: 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% CI, 34.9%-73.3%) and the transplant-related mortality (TRM) was 26.7% (4/15) . The five-year OS was 87.5% (95% CI, 38.7%-66.3%) in eight patients who received haplo-HSCT subsequent to initial therapy and 42.9% (95% CI, 8.5%-65.2%) in patients seven patients who needed salvage therapy prior to haplo-HSCT (χ(2)=2.387, P=0.122) . The five-year OS was 85.7% (95% CI, 50.4%-89.8%) in eight patients who achieved complete response before haplo-HSCT and 42.9% (95% CI, 6.4%-53.0%) in seven patients with partial response (χ(2)=3.185, P=0.074) . Conclusion: The results indicated that haplo-HSCT is a promising method for the treatment of primary HLH in adults.