The clinical observation of treating autoimmune cytopenias after allogeneic hematopoietic stem cell transplantation in children by immunoinduction therapy

Abstract This retrospective study explored safety and efficacy of immunoinduction methods such as Immunosuppressants are reduced and discontinued, with or without PD1 inhibitors, or donor lymphocyte reinfusion (DLI) in the treatment of autoimmune cytopenias (AIC) after allogeneic hematopoietic stem cell transplantation. The clinical data of 20 children admitted to Beijing JingDu Children's Hospital from January 2019 to May 2025 with AIHA (10 cases), ITP (7 cases), and Evans syndrome (3 cases) after allogeneic hematopoietic stem cell transplantation were retrospectively analyzed (5-AA; 4-chronic granulomatous disease; 3-HLH; 2-Wiskott-Aldrich syndrome; 1- Congenital neutropenia; 1-ALL; 1-pyruvate kinase deficiency anemia; 1-Thalassemia; 1-Mucopolysaccharidosis type I; 1-Mucopolysaccharidosis type Ⅱ). Among the 20 cases, 7 cases had mixed chimerism and 13 cases had complete chimerism at the onset of AICs. In all cases, corticosteroids were treated with or without IVIG and rituximab for 1 to 5 weeks, and then Immunosuppressants such as cyclosporine or tacrolimus etc, are reduced and discontinued, combined with or without PD1 inhibitors and DLI were used to treat AICs. The median age of AICs in 20 children was 4 (range:1.25-17) years; median time to development of AICs: 9 (range:4-68) months after transplantation; the median number of recurrent episodes of AICs was 2 (1-5) times. ATG was used in the conditioning regimen of 20 children. Among the 20 children, 5 children cured after stopping immunosuppressants, and 15 children were cured after stopping immunosuppressants combined with PD1 inhibitors or DLI, the average duration of treatment is 2 (0.5-6) months. Among the 20 children, 11 children had grade I~II skin or liver rejection, which were controlled after topical medication or short-term low-dose immunosuppressant therapy. At a median follow-up of 20(2-62) months after discontinuation of treatment, none of the children had recurrence. The immunoinduction therapy of AICs after allogeneic hematopoietic stem cell transplantation is safe and effective.