Clinical Study of UC-MSC Combined With Immunosuppressive Agents in the Treatment of Pediatric HAAA

The goal of this clinical trial is to evaluate the effectiveness of umbilical cord mesenchymal stem cells combined with standard immunosuppressive therapy in children with HAAA, and to provide a new therapeutic idea for children with HAAA. Whether UC-MSC combined with immunosuppressants can improve outcomes in children with HAAA. Whether UC-MSC is safe in the treatment of children with HAAA. Participants will: 1 Age \< 18 years old, gender is not limited; 2 Diagnosis of hepatitis related aplastic anemia according to the criteria for hepatitis related aplastic anemia; 1. The patient has a history of acute prehepatitis, and the course of hepatitis is generally less than 6 months. The main clinical manifestations are fever, jaundice, anemia, bleeding, generally no liver enlargement. 2. Routine blood test: pancytopenia, HGB \< 100 g/L; Absolute neutrophil count \< 1.5×109/L; PLT \< 100×109/L (PLT reduction must be included in case of two-series reduction). Serum aminotransferase levels were elevated at least 200 U/L and hepatitis autoantibodies were negative. 3. Bone marrow aspiration and biopsy confirmed aplastic anemia. 4. Jaundice caused by other reasons and other pancytopenia diseases (such as congenital AA, clonal diseases and autoimmune diseases, etc.) are excluded. 3 No hematopoietic stem cell transplantation (HSCT); 4 The guardian and the subject will participate voluntarily and sign the informed consent;

Inclusion Criteria: 1 Age \< 18 years old, gender is not limited; 2 Diagnosis of hepatitis related aplastic anemia according to the criteria for hepatitis related aplastic anemia; 1. The patient has a history of acute prehepatitis, and the course of hepatitis is generally less than 6 months. The main clinical manifestations are fever, jaundice, anemia, bleeding, generally no liver enlargement. 2. Routine blood test: pancytopenia, HGB \< 100 g/L; Absolute neutrophil count \< 1.5×109/L; PLT \< 100×109/L (PLT reduction must be included in case of two-series reduction). Serum aminotransferase levels were elevated at least 200 U/L and hepatitis autoantibodies were negative. 3. Bone marrow aspiration and biopsy confirmed aplastic anemia. 4. Jaundice caused by other reasons and other pancytopenia diseases (such as congenital AA, clonal diseases and autoimmune diseases, etc.) are excluded. 3 No hematopoietic stem cell transplantation (HSCT); 4 The guardian and the subject will participate voluntarily and sign the informed consent; Exclusion Criteria: 1 Patients will not be enrolled in this study if they meet any of the following conditions: 2. Patients with a history of hematopoietic stem cell transplantation; HIV infection or carrier in the past or at the time of screening; Positive for syphilis; 4. The subject had developed malignant solid tumors of any organ system within 5 years prior to screening; 5. Participated in other clinical trials within 3 months;