Immune and hematopoietic reconstitution after transplantation of cord blood progenitor cells: case report and review of the literature

Transplantation using umbilical cord progenitor cells as the source of the stem cells is increasingly recognized as another form of allogeneic transpl antation with curative intent. However, the different patterns of hematopoi etic and immunological reconstruction have been described in very few patie nts. A 20-month-old boy presented with acute leukemia. He received standard AML induction and consolidation therapy, after which he underwent allogene ic transplantation using HLA-matched sibling stem cells obtained from the u mbilical cord. The preparative regimen consisted of busulfan and cyclophosp hamide. White cell recovery, despite concomitant use of G-CSF, was slow, re miniscent of the engraftment pattern without the use of growth factor. Eryt hroid recovery was best recorded using fetal cell HbF level. Platelet trans fusion independence occurred on day +31. Immunologic reconstitution reveale d an early NK cell recovery by 6 weeks and progressive T cell recovery unti l 3 months, with continued increase in counts thereafter. However, the CD4/ CD8 ratio remained low even at 14 months post-transplantation. Recovery of B cells was slower until day +120. Proliferative response was within normal range on day +120. This report describes the unique engraftment pattern fo llowing umbilical cord blood transplant and emphasizes the pattern of immun ological and hematological reconstitution.