Allogeneic stem cell transplantation in children with leukemia using human leukocyte antigen‐mismatched unrelated donors

Abstract:  Allogeneic HSCT is a curative treatment, when chemotherapy fails, for certain malignant diseases. In Europe, only 15% of the indicated children have an HLA‐matched sibling available; in 65–70% of others, HLA allele‐matched (9–10/10) UDs can be identified. For the rest, it is necessary to identify other alternative donors (HLA‐mismatched family or unrelated cord blood). We present our data of HSCT using HLA partially allele‐mismatched (7–8/10) UDs in 24 children with leukemia. Uniform GvHD prophylaxis was used (rATG, CsA and MTX). Acute GvHD grade II was diagnosed in 70.8% of the patients and grade III–IV in 12.5%. Overall incidence of chronic GvHD was 38.7% (extensive in 30%). The probability of EFS was 60.3% (95% CI 35.5–78.1) and OS was 74.9 (95% CI 49.1–88.9). No difference in survival between PBSC and BM recipients was observed. TRM at day + 100 was 4%, and overall was 12.5%. We conclude that used combination of drugs for GvHD prophylaxis is efficient even for patients transplanted with grafts from a HLA‐mismatched UDs. It enables stable engraftment, good control of GvHD, full reconstitution of immunity, and is not connected with unacceptable transplant‐related mortality.