Neonatal myasthenia gravis: antigenic specificities of antibodies in sera from mothers and their infants.

Transient neonatal myasthenia gravis (MG) is a human model of passively transferred MG. In an effort to understand the characteristics of the most pathogenic antibodies in MG, we studied the fine antigenic specificities of anti-AChR antibodies in sera from 21 MG mothers (nine of which had transiently transferred the disease) and 17 of their infants. Although in a few cases significant differences in antibody specificities were observed between mothers and infants, whether myasthenic or not, generally the antigenic specificities of the antibodies in sera from infants were very similar to those of their mothers. Furthermore, no characteristic differences were detected between the antibody repertoires of mothers who transferred the disease and those who did not.