SIGNIFICANTLY INCREASED MATERNAL AND FETAL IGG AUTOANTIBODY LEVELS TO52 KD RO(SS-A) AND LA(SS-B) IN COMPLETE CONGENITAL HEART-BLOCK

Antibodies to Ro(SS-A) are an important laboratory parameter of congen ital heart block (CHB), but the maternal presence of anti-Ro(SS-A) ant ibodies does not always lead to this fetal acquired autoimmune disease . The current study investigated quantitative and qualitative differen ces of anti-52, -60 kD Ro(SS-A), -La(SS-B) and -U1RNP(-C, -A, -68 kD) autoantibodies (either IgG or IgM) in sera derived from 16 infants wit h CHB and their mothers compared to eight healthy anti-Ro(SS-A) positi ve infants (controls) born to SLE mothers. No serum sample contained I gM. autoantibodies of the specificities investigated. Anti-60, 52 kD R o(SS-A) and La(SS-B) IgG antibodies coincided in 9/16 CHB cases, exclu sively (P<0.05). Associated anti-52 kD Ro(SS-A) and -La(SS-B) IgG anti bodies were detected in 14/16 CHB and in 3/8 control cases (P<0.05). A nti-U1RNP 68 kD antibodies occurred in 1/16 CHB infants and in 4/8 con trols. In general, newborn and maternal antibody patterns and reactivi ties were similar in all cases investigated. The fetal CHB sera contai ned significantly higher IgG levels of anti-52 kD Ro(SS-A) (P<0.005) a nd -La(SS-B) (P<0.005) compared to control samples. Sera from mothers with CHB children had significantly higher levels of anti-52 kD Ro(SS- A) (P<0.015) and -La(SS-B) (P<0.015) IgG antibodies than those of the control group. Thus, the coincidence of anti-52 kD, -60 kD Ro(SS-A) an d -La(SS-B) IgG antibodies as well as significantly increased levels o f antibodies to 52 kD Ro(SS-A) and La(SS-B) are associated with eviden ce of complete congenital heart block. The data suggest that the known associated humoral autoimmune findings are exclusively of maternal or igin. (C) 1995 Academic Press Limited