[A case of anti-titin antibody positive nivolumab-related necrotizing myopathy with myasthenia gravis].

Abstract

A 53-year-old man suffering from squamous cell lung cancer presented with bilateral ptosis and bulbar palsy a month after initial treatment with the immune checkpoint inhibitor nivolumab. The symptoms showed worsening from midday, suggesting myasthenia gravis (MG), although anti-AChR antibody was negative. Although no muscle weakness was detected, the CK level was elevated to 5,255 IU/l, and MRI of the thigh revealed inflammation of the bilateral rectus femoris muscle. A muscle biopsy showed signs of necrotizing myopathy with expression of sarcolemmal HLA class I and accumulation of macrophages, CD4, CD8, and CD20-positive lymphocytes. Positivity for anti-titin antibody, one of the anti-striated muscle antibodies, was evident. The patient was diagnosed as having nivolumab-related necrotizing myopathy with myasthenia gravis, an immune-related adverse event (irAE). Treatment with prednisolone rapidly ameliorated the symptoms, and the serum CK level normalized. There have been several reports of nivolumab-related myositis with MG. On the basis of the muscle pathology and antibody data, we were able to clarify that necrotizing myopathy was related to the pathogenesis of this case.

• Authors: Aiko Isami, Ayaka Uchiyama, Yuichi Shimaoka, Shigeaki Suzuki, Izumi Kawachi, Nobuya Fujita
• Journal: Rinsho shinkeigaku = Clinical neurology (Rinsho Shinkeigaku) Vol. 59 Issue 7 Pg. 431-435 (Jul 31 2019) ISSN: 1882-0654 [Electronic] Japan
• PMID: 31243249 (Publication Type: Case Reports, Journal Article)

Chemical References

• Autoantibodies
• Biomarkers
• Connectin
• Nivolumab
• Prednisolone

Topics

• Autoantibodies (blood)
• Biomarkers (blood)
• Carcinoma, Squamous Cell (drug therapy)
• Connectin (immunology)
• Humans
• Lung Neoplasms (drug therapy)
• Male
• Middle Aged
• Muscular Diseases (chemically induced, diagnosis, drug therapy, pathology)
• Myasthenia Gravis (chemically induced, diagnosis, drug therapy)
• Necrosis
• Nivolumab (adverse effects, therapeutic use)
• Prednisolone (administration & dosage)
• Quadriceps Muscle (pathology)
• Treatment Outcome