Immune Reconstitution in Pediatric Aplastic Anemia after Allogeneic Hematopoietic Stem-cell Transplantation

Background: Previous studies had revealed that immune reconstitution (IR) after allogeneic hematopoietic stem-cell transplantation (allo-HSCT) affected the clinical prognosis of patients. However, few studies were based on pediatric patients and patients with aplastic anemia (AA). The purpose of this research was to analyze IR of pediatric AA after HSCT and further explore its clinical prognostic value. Methods: The whole of 61 pediatric patients with AA who underwent HSCT were enrolled. Lymphocyte subsets count in peripheral blood, CD4⁺/CD8⁺ T cell ratio, and serum concentration of immunoglobulins were detected using flow cytometry at regular intervals after HSCT. Results: Innate immunity recovered faster than adaptive immunity, T lymphocytes recovered faster than B lymphocytes. The number of transfused CD34⁺ cells and the implantation time of ANC significantly affected the early rapid IR of CD3⁺ T cells. The degree of HLA site coincidence significantly affected the early rapid IR of CD19⁺ B cells. The number of transfused MNC and CD34⁺ cells significantly affected the early rapid IR of CD56⁺ NK cells. The overall survival (OS) and failure-free survival (FFS) of CD56⁺ NK cells in early rapid IR group were higher than those in non-IR group. The CD3⁺ T cell early rapid IR group and CD8⁺ T cell early rapid IR group had higher OS than the non-IR group. Conclusion: Early rapid IR after HSCT is a good predictor of clinical prognosis in children with AA. This study provides a reasonable prediction for early rapid IR, which may improve clinical outcomes of children.