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INTRODUCTION: Some myasthenia gravis (MG) patients are refractory to conventional treatments. METHODS: To describe the clinical features of refractory MG (RMG) and explore the association with human leukocyte antigen HLA-DRB1 alleles, a cohort study of 114 consecutive MG patients was performed. Patients were classified as RMG based on predefined criteria. RESULTS: Twenty-two patients were found to have RMG (19.3%). There were no differences between non-RMG and RMG patients with respect to sex, age of onset, abnormal 3-Hz repetitive nerve stimulation, anti-acetylcholine receptor antibody positivity, thymectomy, thymoma or thymic hyperplasia, and polyautoimmunity. HLA-DRB1*03 was more frequent in the non-RMG vs. control population (P = 3 × 10-6 ). The HLA-DRB1*13 allele was less frequent in non-RMG patients compared with controls (P = 0.002), and less frequent in the non-RMG group compared with the RMG group (P = 0.003). DISCUSSION: HLA-DRB1*03 was more common in non-RMG, and the HLA-DRB1*13 allele appeared to have a protective role, as reported previously in other autoimmune disorders. Muscle Nerve 60: 188-191, 2019.

Original publication




Journal article


Muscle Nerve

Publication Date





188 - 191


human leukocyte antigens, myasthenia gravis, polyautoimmunity, refractory, thymoma MG, Adult, Age of Onset, Autoantibodies, Case-Control Studies, Cohort Studies, Female, Genetic Predisposition to Disease, HLA-DRB1 Chains, Humans, Male, Middle Aged, Myasthenia Gravis, Portugal, Protective Factors, Receptors, Cholinergic, Thymectomy, Thymoma, Thymus Hyperplasia, Thymus Neoplasms, Young Adult