ASSOCIATION OF NEONATAL MYASTHENIA-GRAVIS WITH ANTIBODIES AGAINST THEFETAL ACETYLCHOLINE-RECEPTOR

The specificities of autoantibodies directed against the acetylcholine receptor (AChR) for embryonic and adult muscle AChR were studied in 2 2 mothers with myasthenia gravis (MG) and in their newborns using huma n fetus and normal adult muscle AChR preparations. 12 mothers had tran smitted MG to their neonates with, in three cases, antenatal injury. A clear correlation was found between occurrence of neonatal MG (NMC) a nd the high overall level of anti-AChR antibodies (embryonic or adult muscle AChR). However, a strong correlation was also found between occ urrence of NMG and the ratio of anti-embryonic AChR to anti-adult musc le (Te/Ta) AChR antibodies (P < 0.0002). Taken together, these data su ggest that autoantibodies directed against the embryonic form of the A ChR could play a predominant role in the pathogenesis of NMG. Paradoxi cally, the three cases with antenatal injury presumably the most sever e form of NMG, were not associated with high Te/Ta. At the clinical le vel, these observations could prove helpful in the prediction of trans mission of NMG.