Congenital heart block: HLA differences between affected children and healthy siblings in four Finnish families

Congenital heart block without intracardiac anatomic malformations is a potentially lethal disease affecting children and newborns. The mother often has an autoimmune disorder with autoantibodies against SS‐A/Ro and/or SS‐B/La antigens. However, only a minority of the children of these mothers develop complete heart block. It is believed that the maternal antibodies are pathogenic, but other immunological mechanisms such as cell‐mediated injury cannot be excluded. Maternal cells may recognize fetal antigens adjacent to fetal HLA, and thus some children may be more susceptible to heart block than others, depending on their HLA genetics. The purpose of this study was to evaluate whether there are HLA differences between children with heart block and their healthy siblings. Six affected children in four families and their siblings were studied. MHC class I were typed serologically and class II and some non‐HLA alleles were typed by DNA techniques. DQB1*03/04 were seen more often in the affected children than in the siblings. Some other differences were also seen in the other antigens of the MHC area.