Transdifferentiation of cardiac fibroblasts, a fetal factor in anti-SSA/Ro-SSB/La antibody-mediated congenital heart block.

The signature lesion of autoantibody-associated congenital heart block (CHB) is fibrosis of the conducting tissue. To date, participation of myofibroblasts in the cascade to injury has been unexplored. The importance of myofibroblast/macrophage cross-talk is demonstrated by the novel finding of these cell types in the heart of a neonate dying of CHB.