Lymphocyte subset reconstitution after unrelated cord blood or bone marrow transplantation in children

P>We report the post-transplant lymphocyte subset recovery of 226 children treated with Unrelated Cord Blood transplant (UCBT) (n = 112) or Unrelated Bone Marrow Transplant (UBMT) (n = 114) for malignant or non-malignant diseases. Absolute numbers of natural killer (NK), B and T cells were monitored by flow cytometry up to 5 years post-transplant. Immunological endpoints were: time to achieve a CD3+ cell count > 0 center dot 5 and 1 center dot 5 x 109/l, CD4+ > 0 center dot 2 and 0 center dot 5 x 109/l, CD8+ > 0 center dot 25 x 109/l, CD19+ > 0 center dot 2 x 109/l, NK > 0 center dot 1 x 109/l. These endpoints were analysed through the use of cumulative incidence curves in the context of competing risks. CD8+ T cell recovery was delayed after UCBT with a median time to reach CD8+ T cells > 0 center dot 25 x 109/l of 7 center dot 7 months whereas it was 2 center dot 8 months in UBMT (P < 0 center dot 001). B cell recovery was better in UCBT, with a median time to reach CD19+ cells > 0 center dot 2 x 109/l of 3 center dot 2 months in UCBT and 6 center dot 4 months in UBMT (P = 0 center dot 03). Median time for CD4+ T cell and NK cell recovery was similar in UCBT and UBMT. CD4+ T cells recovery was negatively correlated to age (better reconstitution in younger patients, P = 0 center dot 002). CD8+ T cells recovery was shorter in recipients with a positive cytomegalovirus serology (P = 0 center dot 001).