Prevalence of myasthenia gravis and associated autoantibodies in paraneoplastic pemphigus and their correlations with symptoms and prognosis.
BACKGROUND
Paraneoplastic pemphigus (PNP) involves multiple organs, but little is known about its neurological involvement.


OBJECTIVE
To investigate the symptoms, prognosis and profiles of associated autoantibodies in myasthenia gravis (MG), and their correlations in patients with PNP.


METHODS
Fifty-eight patients with PNP were assessed for myasthenic symptoms and laboratory evidence. Serum autoantibodies against acetylcholine receptor (AChR), acetylcholinesterase (AChE), titin, ryanodine receptor (RyR) and muscle-specific kinase (MuSK) were measured by enzyme-linked immunosorbent assay. Patients with pemphigus vulgaris (PV), pemphigus foliaceus (PF), connective tissue disease (CTD) and non-PNP MG (NP-MG), and healthy donors, served as controls. These autoantibodies in PNP were also compared in the presence or absence of dyspnoea or muscle weakness. Cox regression and log-rank tests were used for survival analysis.


RESULTS
Overall 39% of patients with PNP experienced muscle weakness, and 35% were diagnosed with MG. Moreover, 35% had positive anti-AChR and 28% had anti-AChE antibodies, similarly to NP-MG (33% and 17%, respectively, P > 0·05). However, both were negative in all patients with PV, PF and CTD and healthy donors (P < 0·005). No other antibodies showed significant differences among groups. Anti-AChR and anti-AChE antibody levels were significantly increased in patients with PNP with dyspnoea, while anti-AChR, anti-titin and anti-RyR were significantly increased in patients with PNP with muscle weakness (P < 0·05). Nevertheless, levels and positive rates of these autoantibodies showed no significant differences between PNP with Castleman disease and thymoma. Although anti-AChE levels impacted survival duration (P  =  0·027, odds ratio 3·14), MG complications did not affect the overall survival percentage in PNP.


CONCLUSIONS
MG is a complication of PNP. Anti-AChR and anti-AChE antibodies are prominent in patients with PNP, especially those with dyspnoea.
Department of Dermatology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China; Beijing Key Laboratory of Molecular Diagnosis of Dermatoses, Beijing, China.
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R
Wang
J
J
Li
M
M
Wang
H
H
Hao
X
X
Chen
R
R
Li
X
X
Zhu
D000110:Acetylcholinesterase / Q000276:immunology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000378:metabolism*; D064211:Connectin / Q000276:immunology; D004417:Dyspnea / Q000209:etiology / Q000276:immunology / Q000401:mortality; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology / Q000276:immunology / Q000401:mortality; D009157:Myasthenia Gravis / Q000209:etiology / Q000276:immunology* / Q000401:mortality; D010257:Paraneoplastic Syndromes / Q000150:complications / Q000276:immunology* / Q000401:mortality; D010392:Pemphigus / Q000150:complications / Q000276:immunology* / Q000401:mortality; D011379:Prognosis; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology; D019837:Ryanodine Receptor Calcium Release Channel / Q000276:immunology; D013945:Thymoma / Q000150:complications / Q000276:immunology / Q000401:mortality; D013953:Thymus Neoplasms / Q000150:complications / Q000276:immunology / Q000401:mortality; D055815:Young Adult
D001323:Autoantibodies; D064211:Connectin; D011950:Receptors, Cholinergic; D019837:Ryanodine Receptor Calcium Release Channel; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D000110:Acetylcholinesterase