HEMATOPOIETIC AND IMMUNE RECOVERY AFTER TRANSPLANTATION OF CORD-BLOODPROGENITOR CELLS IN CHILDREN

Matched related cord blood transplantation (CBT) has been successfully used to rescue patients undergoing myeloablative therapy, However, fe w data are available on the kinetics of hematological and immunologica l reconstitution of CBT recipients, We have investigated the hematolog ical engraftment and immune recovery following related CBT in three pa tients, with acute lymphoblastic leukemia, aged 10, 9 and 7 years and with a body weight of 31, 40 and 25 kg, respectively, All patients eng rafted and none experienced acute or chronic graft-versus-host disease , The time needed to achieve granulocyte recovery was 13, 26 and 29 da ys, respectively and platelet recovery occurred in 28, 49 and 51 days, All patients presented a marked increase of HbF, the values observed being much greater than those documented in patients given marrow tran splantation and comparable with those observed in normal children in t he first year of age, The recovery of T cell immunity, as well as that of natural killer subpopulations, mimicked that described in BMT reci pients, a quicker return of CD8(+) T cells determining the characteris tic inversion of CD4/CD8 ratio, An impressive increase in the percenta ge and absolute number of B lymphocytes, apparently not related to vir al infections, was demonstrable in all three cases, These data suggest that CBT recipients can experience a slight delay in hematological re covery when compared with patients given BMT, The reconstitution of er ythropoiesis seems to recapitulate the ontogenetic pattern and the kin etics of recovery of the immune system reproduce that observed after B MT with the peculiarity of B cell expansion in peripheral blood.