[Two children with severe recurrent infections and the X-linked hyper-IgM syndrome].

A boy suffered from severe recurrent intestinal infections from the age of 8 months onwards; investigation into an immune disorder ultimately resulted in the diagnosis of 'hyper-IgM syndrome'. He was treated successfully with bone marrow transplantation, using an HLA-matched donor. Another boy had severe recurrent respiratory tract infections from the age of 3 months onwards. At the age of 6.5 years, 'hyper-IgM syndrome' was diagnosed. No suitable donor was available. In addition, he developed sclerosing cholangitis and end-stage liver disease, making a combined bone marrow and liver transplantation too risky. He died at 10.5 years of age. X-linked hyper-IgM syndrome is a rare congenital immunodeficiency disorder, characterised by a defect in both humoral and cellular immune responses. Deficiency in the membrane glycoprotein CD40 ligand (expressed on activated T-cells) compromises T-cell interactions with antigen-presenting cells. In a child with severe recurrent infections, and with dysgammaglobulinaemia with a normal or increased IgM level, the diagnosis of 'X-linked hyper-IgM syndrome' should be considered.