Prolonged hypogammaglobulinemia in children after allogeneic hemopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is a key treatment strategy for life-threatening hematologic and immunologic diseases. Immune reconstitution after allogeneic HSCT is a complex and multistage process, which is critical to the recovery of the patient's immune function and to the reduction of the risk of infectious complications. Studies show that most patients experience a significant improvement in immune function 6-12 months after transplantation; however, a full recovery may take up to 2 years or more. One of the major complications of allogeneic HSCT is prolonged hypogammaglobulinemia - low serum immunoglobulin G levels for more than 2 years after allogeneic HSCT. In the absence of a clearly defined threshold for hypogammaglobulinemia, the generally accepted definition is a serum immunoglobulin G level below 5 g/L. Impaired antibody formation and the occurrence of prolonged hypogammaglobulinemia in children after allogeneic HSCT are complex problems that require careful monitoring and appropriate management. Timely restoration of B cell number and function is critical to reduce the risk of infectious complications and improve the quality of patients' life.