Impaired antibody immune response in patients with late onset of B-cell reconstitution. (A) The number of total IgM, IgG, and IgA antibody-secreting cells (ASCs) and (B) the number of TT-specific IgG and pneumococcal polysaccharide-specific IgM and IgG ASCs was determined by ELISpot analysis. Shown is the number of spots obtained per 10³ seeded cells at day 180 after allo-HSCT for patients with early (dark gray bars, n = 11) or late (white bars, n = 9) onset of B-cell reconstitution. Light gray bars in the back show mean spot numbers ± SEM obtained for HCs (n = 11). Statistically significant differences in ASC numbers between early and late onset patients are depicted. * P ≤ .05.