¹Service d'Hémato-immunologie, Hôpital Robert Debré, Paris, France

²Laboratoire d'Immunologie, Hôpital Robert Debré, Paris, France

Correspondence to: M Duval, Service d'Hémato-Oncologie, Hôpital Sainte-Justine, 3175, chemin Côte-Sainte-Catherine, Montréal, QC, Canada, H3T 1C5

Antithymocyte globulin is widely used before haematopoietic transplantation with HLA-matched unrelated donors or mismatched relatives to prevent rejection and graft-versus-host disease (GVHD). However, optimal dosage is still under debate. Thirty-one consecutive children, mainly with haematological malignancies, were transplanted in a single institution with such donors, selected by HLA-A -B compatibility by serology and DRB1* by DNA typing. Antithymocyte globulin (Thymoglobuline; Sangstat) was infused at days -3, -2, -1. Total dosage varied: 16 patients received a median of 7.5 mg/kg (2.5 to 10.5: low-dose group), and 15 a median of 15.5 mg/kg (14.4 to 19.4: high-dose group). Post-transplant GVHD prophylaxis consisted of cyclosporine, short-course methotrexate and steroids. CD3⁺, CD4⁺ and CD19⁺ cell reconstitution was slower in the high-dose group. Median time to reach 100 CD4⁺ cells was 8 months vs 4 months (P = 0.03). Median time to normal CD19⁺ cells was 16 months vs 8 months (P = 0.01). CD16⁺CD56⁺ and CD8⁺ cell reconstitution was similar. Nine patients in the high-dose group and two in the low-dose group experienced life-threatening opportunistic infections (P = 0.009). Although obtained from a limited number of patients, our data suggest that a higher pre-graft dose of antithymocyte globulin may negatively influence immune reconstitution.

Bone Marrow Transplantation (2002) 30, 421-426. doi:10.1038/sj.bmt.1703680

allogeneic haematopoietic transplantation; unrelated donor; antithymocyte globulin; graft-versus-host disease; immune reconstitution