ISOLATED CONGENITAL HEART-BLOCK - LONG-TERM OUTCOME OF MOTHERS AND CHARACTERIZATION OF THE IMMUNE-RESPONSE TO SS-A RO AND TO SS-B/LA/

Objective. To study the long-term outcome of mothers of children with isolated congenital heart block (CHB) and to characterize the maternal autoantibody response to SS-A/Ro and SS-B/La. Methods. A retrospectiv e clinical study of 33 mothers a mean of 11.2 years (SD 9.2 years, ran ge 0-32 years) after the delivery of their first child with CHB. A cli nical and immunologic study of 31 of these mothers, compared with 89 h ealthy mothers, 45 mothers with systemic lupus erythematosus (SLE), an d 19 mothers with primary Sjogren's syndrome (SS), all of whom had hea lthy children. The specificity of the autoantibody responses to SS-A/R o and SS-B/La was studied by enzyme-linked immunosorbent assays using purified human recombinant antigens and affinity-purified antigens. Re sults. By the time of the analysis, 2 (6%) of the 33 mothers of CHB ch ildren had died and 6 (18%) had met the criteria for SLE. As a group, mothers of CHB children had clinical and immunologic characteristics m ore closely related to primary SS than to SLE or any other connective tissue disease. The predominant autoantibody response was to the SS-A/ Ro antigens, notably to the 52-kd SS-A/Ro protein (prevalence 97%). Co mpared with controls with SLE, mothers of CHB children had higher tite rs of antibodies to recombinant 52-kd and 60-kd SS-A/Ro proteins and t o the affinity-purified SS-A/Ro antigen (P < 0.05, P < 0.01, and P < 0 .001, respectively). Compared with controls with primary SS, the autoa ntibody responses were similar. Conclusion. The predominant autoimmune disorder in mothers of children with CHB is subclinical primary SS. A ntibodies to SS-A/Ro appear to be a prerequisite for the development o f CHB.