B Cell Reconstitution and Influencing Factors After Hematopoietic Stem Cell Transplantation in Children

Abstract

B cell reconstitution after hematopoietic stem cell transplantation (HSCT) is variable and influenced by different patient, donor, and treatment related factors. In this review we describe B cell reconstitution after pediatric allogeneic HST, including the kinetics of reconstitution of the different B cell subsets and the development of the B cell repertoire, and discuss the influencing factors. Observational studies show important roles for stem cell source, conditioning regimen, and graft vs. host disease in B cell reconstitution. In addition, B cell recovery can play an important role in post-transplant infections and vaccine responses to encapsulated bacteria, such as pneumococcus. A substantial number of patients experience impaired B cell function and/or dependency on Ig substitution after allogeneic HSCT. The underlying mechanisms are largely unresolved. The integrated aspects of B cell recovery after HSCT, especially BCR repertoire reconstitution, are awaiting further investigation using modern techniques in order to gain more insight into B cell reconstitution and to develop strategies to improve humoral immunity after allogeneic HSCT.

Keywords: B lymphocyte; allogeneic; hematopoietic stem cell transplantation; immune reconstitution; pediatric; subsets.

Figure 1

(A) Schematic representation of peripheral B-cell development. (B) Hypothetical scheme of B cell subset reconstitution after HSCT based on literature. The first cells emerging in the peripheral blood are the transitional B cells. In the course of the first year, the transitional B cells decrease in number and are replaced by mature naïve B cells. These mature B lymphocytes further differentiate into memory B cells and plasma cells.