Polyclonal anti-T-cell globulin as part of the preparative regimen for pediatric allogeneic stem-cell transplantation.

To prevent graft rejection and graft-versus-host disease (GvHD) after allogeneic stem-cell transplantation (ASCT), 56 children were given polyclonal anti-T-cell globulin (ATG) as part of the conditioning regimen. Of the 56 children in the cohort, 27 had a non-malignant disease and 29 had different hematological malignancies. Eight were in first remission of leukemia and the remainder in later stages. Donors were in 16 cases a human leucocyte antigen (HLA)-identical sibling and in 40 a matched unrelated donor (MUD). The control group comprised 16 patients with an HLA-identical donor; the children in this group were not treated with ATG. Side-effects related to the ATG treatment occurred in 63% of the patients and included fever, chills, headache, dyspnoea, nausea/vomiting, body pain, fall in blood pressure, and transient respiratory arrest. Engraftment occurred in 55 (98%) of the ATG-treated patients at a median of 17 (11-27) days after ASCT. One rejection occurred at 23 days post-SCT. The probabilities of acute graft-versus-host disease (GvHD) of grades II-IV were 6% for patients with an HLA-identical donor, 12% for controls, and 26% for the MUD group. Chronic GvHD occured in 20%, 50%, and 50% of patients in the three groups, respectively. Transplant-related mortality rates at 100 days were 6%, 6%, and 7%, respectively. The 5-yr survival rate was 94% and 81% using sibling donors, with and without ATG respectively, and 53% using unrelated donors (p = 0.002). Disregarding donor type, among the ATG-treated patients 5-yr survival rates were 46% in patients with a malignant disease and 77% in non-malignant disorders. Relapse and relapse-free survival rates were 42% and 46%, respectively. Five out of 12 patients who showed an early full donor chimerism in the T-cell lineage developed acute GvHD of grades II-IV, compared to none out of 13 patients being mixed chimeras (p = 0.01). Hence, the use of polyclonal ATG as part of conditioning prior to ASCT in children is safe and the survival rate encouraging.