COMPARISON OF ANTIBODY TITER TO HUMAN AND RAT ACETYLCHOLINE-RECEPTOR IN MYASTHENIA-GRAVIS

Antibody titer to acetylcholine receptor (AChR Ab) was measured in 34 patients with myasthenia gravis (MG) using an immunoprecipitation meth od with human and rat AChR as antigens, to study the reliability of th ese assay systems and the cross-reactivity between human and rat AChR. There was a good correlation in the titer of Ah to AChR between human and rat (P < 0.01) when Ah titers were expressed logarithmically. The titer of Ab to human AChR was higher in a group of patients with a hi gh concentration of AChR Ab and lower in a group with a low concentrat ion of AChR Ah than that to rat AChR. This indicates that there may be distinctive characteristics in AChR Ab between groups of patients wit h high and low concentrations of AChR Ab.