Authors: Hisham Abdel-Azim, Amro Elshoury, Kris M. Mahadeo, Robertson Parkman, Neena Kapoor
Summary:
Although T cell immune reconstitution following allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been well studied, long-term B cell immune reconstitution remains less characterized. We evaluated humoral immune reconstitution among 71-pediatric allo-HSCT recipients. While tetanus toxoid (TT) antibody levels were normal at 1-year post allo-HSCT, anti-polysaccharide carbohydrate (PRP) antibodies remained persistently low for up to 5-years. While naive B cell counts normalized by 6-months, IgM memory B cell deficiency persisted for up to 2-years (P=0.01); switched memory B cell deficiency, normalized by 1-year post allo-HSCT. CD4+ T cell immune reconstitution correlated with that of switched memory B-cells as early as 6-months post allo- HSCT (r=0.55, P=0.002) but did not correlate with IgM memory B cells at any time point post allo-HSCT. Taken together, this suggests that allo-HSCT recipients have impaired antibody immune reconstitution, mainly due to IgM memory B cell maturation block, compared to more prompt T cell dependent switched memory cell immune reconstitution. We further explored other factors that might affect humoral immune reconstitution. The use of total body irradiation (TBI) was associated with lower naive B cells counts at 6-months post-HSCT (P=0.04), and lower IgM (P=0.008) and switched (P=0.003) memory B cells up-to 2-years. Allo-HSCT recipients with extensive chronic graft-versus-host disease (cGVHD) had lower IgM memory B cell counts (P=0.03) up to 2-years post allo-HSCT. The use of cord blood (CB) was associated with better naive (P=0.01), IgM (P= 0.0005) and switched memory (P=0.006) B cells immune reconstitution. These findings may inform future prophylaxis and treatment strategies regarding risk of overwhelming infection, GVHD and post-allogeneic HSCT re-vaccination.
Source:
Biology of Blood and Marrow Transplantation; 2017