[Myasthenia gravis and asymptomatic monoclonal gammapathy. Detection of autoantibody activity of the monoclonal immunoglobulin]

Simultaneous occurrence of "myasthenia gravis" and monoclonal "asymptomatic" gammapathy has been observed in a 83 years old patient. Antistriated muscle antibodies could be detected at a level of 1/1,000 but no antiacetylcholine receptors antibodies. The antibody activity is located both in the monoclonal IgG kappa and in the polyclonal IgG. This case illustrates the frequent occurrence of several auto-immune disorders in a same patient.