Mixed connective tissue disease after thymectomy in refractory myasthenia gravis

Connective tissue diseases, including systemic lupus erythematosus (SLE) and systemic sclerosis are classic models of autoimmunity; diseases with large-scale loss of tolerance and subsequent development of pathogenic autoreactive lymphocytes and tissue targeting autoantibodies. Here we report a case of mixed connective tissue disease, with features of systemic lupus erythematosus and systemic sclerosis developing in a patient 10 years post thymectomy for myasthenia gravis. The patient developed acute cutaneous lupus, Raynaud's with digital ulcers, arthritis and lymphopenia. Her myasthenia continued to be resistant to treatment and her rheumatic disease progressed despite aggressive therapy. We performed a database search of MEDLINE, EMBASE, Scopus, and Web of Science for articles of similar cases post thymectomy from inception to August 2021, using the terms "systemic lupus erythematosus" (or systemic sclerosis, or connective tissue disease) and "myasthenia gravis" and "thymectomy". We identified 41 cases, 28 of SLE post thymectomy, 8 related to systemic sclerosis, 5 with mixed connective tissue disease and highlighted their different presentation and serology. We explore the role of the thymus, tolerance and myasthenia gravis in the development of connective tissue disease. This highlights the complexity of concurrent autoimmune diseases and their autoantibodies.

Critical peripheral ischemia precipitated by severe episode of Raynaud's phenomenon in a patient with aPL-positive systemic lupus erythematosus, upon high titer anti-RNP seroconversion

A 35-year-old female with long standing aPL-positive lupus without history of thromboembolic events, who has developed critical peripheral ischemia (CPI) is described. An episode of severe Raynaud's phenomenon rapidly progressed to an extensive digit-threatening ischemia, involving bilateral hands and feet. She was successfully treated with corticosteroids, anticoagulation, iloprost, sildenafil, and nifedipine. Her serological studies were remarkable for the emergence of high titer anti-RNP seroconversion and an increase in aPL titer, suggesting that these autoantibodies played a role in the pathogenesis of CPI. It is important to note that such observation should herald this potentially devastating complication of systemic lupus erythematosus.