Relationship of maternal autoimmune response to clinical manifestations in children with congenital complete heart block

Objective: To study the autoimmune response in mothers of children with congenital heart block (CHB) diagnosed at different ages and with different clinical manifestations. Patients and methods: Clinical data and sera for the determination of immunological tests were available from 104 mothers of 113 children born between 1950 and 2000 and diagnosed with CHB before the age of 16 y. Prenatal diagnosis was performed in 74 (65%) children of 65 mothers, and 39 (35%) children had postnatal diagnosis of CHB. Maternal antibodies to 52 kd and 60 kd SS-A, and to 48 kd SS-B were determined by time-resolved fluoroimmunoassay (TR-FIA) and to antinuclear antibodies (ANA) by immunoflurescense (IF). Results: Out of the 65 mothers of children with in utero diagnosed CHB, 88% had antibodies to 52 kd SS-A and 83% had ANA. Antibodies to 60 kd SS-A and 48 kd SS-B were less frequently present, in 48% and in 54% of the mothers, respectively. Seven (11%) of the mothers were negative by all immunoassays. Of the 13 mothers of children with in-infancy diagnosed CHB, one mother had high-titer ANA. After 1 y of age, CHB was diagnosed in 26 children; at 1 to 6 y in 16 and after 7 y in 10 children; 1/16 and 1/10 patients had positive antibodies. In all twin pregnancies (n = 4) and in all families with recurring cases of CHB (n = 5), maternal antibodies were positive in at least one assay. The titer of 48 kd anti-SS-B antibodies was significantly higher in children with cutaneous neonatal lupus (98.1 vs 41.0; p = 0.02). All mothers whose children died before the age of 4 y (n = 8) and 85% (11/13) of mothers whose children developed cardiomyopathy had elevated antibody titers in at least one assay. However, we could not find any prognostic value of maternal antibody levels or specificities on the clinical outcome of the children with CHB. Conclusions: Although rare, late detection or postnatal progression of CHB in antibody-mediated CHB should be taken into consideration. Maternal antibody levels or specificities have prognostic effect neither on the clinical outcome of the child with CHB nor on the risk of reappearance in the same family.