Identification and management of fetuses at risk for, or affected by, congenital heart block associated with autoantibodies to SSA (Ro), SSB (La), or an HsEg5-like autoantigen

Abstract

The congenital heart block (CHB), diagnosed in structurally normal hearts, is strongly associated with, if not caused by, maternal SSA/SSB antibodies (Abs). It develops between 16 and 24 weeks' gestation, coincidentally with the increased transplacental IgG passage, and a window of unique cardiac vulnerability. Less is known about rare CHB cases in which neither cardiac malformations nor SSA/SSB Abs are detectable. We report on four pregnant women: patient 1 at high CHB risk (owing to Sjögren's syndrome (SS) and recurrent pregnancy losses), and patients 2-4 with already established CHB (aggravated by hydrops in patient 2). Abs were found directed to SSA/SSB (patients 1-3) or to an HsEg5-like autoantigen instead (patient 4). During preventive immunoadsorption (IA) from week 19 throughout (patient 1), or therapeutic IA (plus dexamethasone), commenced at week 25 (patient 2), SSA Ab levels decreased per session by 47+/-7 or 80+/-16%, respectively, and hydropic changes resolved. Patient 1 delivered a healthy boy, while patients 2-4 gave birth to CHB-affected children at need for permanent pacing. The irreversibility of complete CHB may justify (a) early ANA screening in all pregnancies (thereby also considering specificities as anti-HsEg5), and (b) preventive immmunoadsorption in high-risk pregnancies (before/during the critical cardiac development phase). This implies controversy, because factors converting risk to disease (in only approximately 2%) are unknown, and prospective randomized treatment studies are not available, given the rarity of CHB.