Heart-stopping antibodies

Women with lupus and rheumatoid arthritis are at increased risk for having babies with congenital heart block, and maternal autoantibodies that cross the placenta are thought to be the main cause. On page 11, Salomonsson et al. show that a subset of autoantibodies that disrupt the calcium homeostasis in heart cells is responsible.Women with autoantibodies specific for an intracellular protein of unknown function called SSA/Ro52 (Ro52) are more likely to have babies with congenital heart block—a condition in which the electrical impulses that regulate the heart beat are disrupted. The pathogenic response has been associated with the presence of antibodies that bind to one peptide on Ro52 called p200, but the mechanism was until recently a mystery.

The authors have now pinpointed the pathogenic response even further by showing that not all p200-specific antibodies...