Anti-Kv1.4 Antibody-positive Nivolumab-induced Myasthenia Gravis and Myositis Presenting with Bilateral Ptosis and Demonstrating Different Pathophysiologies

• Published in: Internal Medicine Vol. 62; no. 20; pp. 3013 - 3020
• Main Authors: Kitazaki, Yuki, Yamamura, Osamu, Usui, Kojiro, Ueno, Asako, Sanada, Sayaka, Sasaki, Hirohito, Endo, Yoshinori, Enomoto, Soichi, Ikawa, Masamichi, Nakamoto, Yasunari, Hamano, Tadanori
• Format: Journal Article
• Language: English
• Published: Tokyo The Japanese Society of Internal Medicine 15-10-2023; Japan Science and Technology Agency
• Subjects: anti-muscular voltage-gated potassium channel antibodies; Case Report; Cell activation; Channel gating; Dyspnea; Facial paralysis; immune-related adverse event; Internal medicine; Lymphocytes T; Methylprednisolone; Myasthenia gravis; Myositis; Neuromuscular junctions; nivolumab; Paralysis; Potassium channels (voltage-gated); Respiration
• ISSN: 0918-2918; 1349-7235
• DOI: 10.2169/internalmedicine.0739-22

Nivolumab blocks inhibitors of T-cell activation and restores antitumor immunity but promotes T-cell activity in host tissues by blocking inhibition of the T-cell function, resulting in immune-related adverse effects. We herein report an 80-year-old man presenting with nivolumab-related myasthenia gravis with anti-muscular voltage-gated potassium channel-complex (Kv1.4) antibodies. On day 29 after nivolumab administration, he simultaneously developed rapidly progressing right ptosis and left facial paralysis. Nivolumab administration was discontinued. He subsequently presented with bulbar paralysis, dyspnea, and muscle weakness and received intravenous immunoglobulin, methylprednisolone, and plasma exchange. The severity of nivolumab-related myasthenia gravis with anti-Kv1.4 antibodies presented with diverse clinical findings.