Preceding immunosuppressive therapy with antithymocyte globulin and ciclosporin increases the incidence of graft rejection in children with aplastic anaemia who underwent allogeneic bone marrow transplantation from HLA-identical siblings.

The incidence of graft rejection was determined in 66 children with acquired aplastic anaemia (AA) following bone marrow transplantation (BMT) from a related donor. Eleven of 65 evaluable patients experienced either early or late rejection. Multivariate analysis identified previous immunosuppressive therapy with antithymocyte-globulin (ATG) and ciclosporin (CsA) as a risk factor for graft rejection (relative risk: 16.6, P = 0.001). Patients who received ATG and CsA had a significantly lower probability of failure-free survival than those who did not (69.7 +/- 6.2% vs. 87.9 +/- 8.0%, P = 0.044). These results suggest that BMT should be instituted immediately in children with severe AA who have human leucocyte antigen-identical siblings.