Diagnostic significance of IgG, C3, and C9 at the limb muscle motor end-plate in minimal myasthenia gravis.
We detected deposits of IgG, C3, and C9 (immune complexes) at the limb muscle motor end-plates (biceps brachii muscle) in 16 of 19 patients who exhibited only ocular signs and symptoms of myasthenia gravis that were improved by intravenous injections of edrophonium chloride. Circulating anti-acetylcholine receptor (anti-AChR) antibodies were negative in 6 of the 16 patients, but the motor end-plate fine structure in the postsynaptic regions was abnormal in all 16. Single-fiber EMG revealed no abnormalities in 8 of 13 patients studied. Our results indicate that the detection of immune complexes at the limb muscle end-plate provides a highly sensitive and confirmative method for diagnosing patients with minimal or atypical myasthenia gravis who have no detectable anti-AChR antibodies in their serum.
Tsujihata
M
M
School of Allied Sciences, Nagasaki University, Japan.
Yoshimura
T
T
Satoh
A
A
Kinoshita
I
I
Matsuo
H
H
Mori
M
M
Nagataki
S
S
D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000032:analysis; D000936:Antigen-Antibody Complex / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D003176:Complement C3 / Q000032:analysis*; D004576:Electromyography; D005121:Extremities; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D009045:Motor Endplate / Q000032:analysis*; D009132:Muscles / Q000294:innervation; D009157:Myasthenia Gravis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D009469:Neuromuscular Junction / Q000032:analysis*; D011950:Receptors, Cholinergic / Q000276:immunology
D000906:Antibodies; D000936:Antigen-Antibody Complex; D003176:Complement C3; D007074:Immunoglobulin G; D011950:Receptors, Cholinergic