[Acetylcholine receptor antibody titer, sensitivity to curare electromyogram and disease severity in myasthenia gravis].

All of 39 rabbits immunized with acetylcholine receptors invariably formed anti-AChR Abs and some of them developed muscular weakness or flaccid paralysis. Pharmacological, physiological and ultrastructural studies indicated that the pathology of experimental autoimmune myasthenia gravis in rabbits resembled that of human myasthenia gravis. The titer of anti-AChR Abs correlated poorly with disease severity and did not simply predicted the muscular weakness. The results ruled out the possibility that antigenic modulation of AChR was sufficient to account for the induction of myasthenia gravis. There was a close relationship between the sensitivity to curare and disease severity, but only part of immunized animals appeared electromyogram change. This led us to conclude that serum anti-AChR concentration would not be the single pathological factor in myasthenia gravis and disease severity may correlate with amount of normal AChR.