Seronegative myasthenia gravis: clinical features, response to therapy and synthesis of acetylcholine receptor antibodies in vitro.
Circulating autoantibodies against the acetylcholine receptor (AChR-Ab) are an important diagnostic tool in myasthenia gravis (MG). Lack of antibodies may cast doubt upon the diagnosis, the immune-mediated mechanism and the nature of the antigen. We examined clinical and laboratory features, response to immunotherapy and production of AChR-Ab in vitro, in 12 seronegative MG patients who were followed up for 2-30 years. It was possible to divide those patients into 2 groups: 7 patients with systemic muscle weakness, with a severe disease and with response to immunosuppressive therapies. The other group of 5 patients was characterized by oculobulbar symptomatology, a relatively benign course and immunotherapy was ineffective in 3 treated patients. Five patients underwent thymectomy and gland histology was normal in all of them. In none of 9 patients examined, were AChR-Ab synthesized in vitro (compared to 65% of seropositive myasthenic patients). Thus seronegative generalized MG is probably an autoimmune disease though the autoantigen is presently unknown and is responsive to immunosuppressive treatment. Seronegative oculobulbar MG might represent a separate disease entity in which immunological mechanisms play no significant role.
Birmanns
B
B
Department of Neurology, Hadassah University Hospital, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Brenner
T
T
Abramsky
O
O
Steiner
I
I
D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology* / Q000473:pathology; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008213:Lymphocyte Activation; D008297:Male; D009157:Myasthenia Gravis / Q000145:classification / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D009468:Neuromuscular Diseases / Q000175:diagnosis; D011950:Receptors, Cholinergic / Q000276:immunology*; D013934:Thymectomy
D001323:Autoantibodies; D001324:Autoantigens; D007166:Immunosuppressive Agents; D011950:Receptors, Cholinergic