Systemic and neurologic autoimmune disorders and antibody seropositivity associated with neurosarcoidosis

Comorbid autoimmune disorders and non-specific antibody seropositivity have been commonly reported in prior studies of systemic rheumatologic disorders and neuroimmune diseases. As a disorder without a reliable diagnostic biomarker with diagnosis further complicated by the need for extensive testing to rule-out alternative etiologies, their prevalence in clinical scenarios concerning for neurosarcoidosis has become increasingly relevant. While data related to systemic sarcoidosis has been published, data specific for neurosarcoidosis has not, which is especially important given the limitations in diagnosis posed by the challenges of neural tissue biopsy.

Adult patients with probable or definite neurosarcoidosis were included if data pertinent to the patient's medical history and serum autoantibody testing were available for review. The frequencies of 18 comorbid autoimmune disorders and seropositivity for 37 antibodies were calculated for the cohort.

151 patients were included, the majority of whom were female (87, 57.6%) and Black (113, 74.8%). Patients were aged on average 45.9 years (SD +/- 11.1 years) at the time of neurosarcoidosis diagnosis. Twenty-nine (29/151, 19.2%) unique patients were diagnosed with at least one other autoimmune disorder, including 27 (27/151, 17.9%) with at least one additional systemic autoimmune disorder (most commonly rheumatoid arthritis and inflammatory bowel disease) and two (2/151, 1.3%) with one other neuroimmune disorder (myasthenia gravis, multiple sclerosis). Three (3/151, 2.0%) patients were diagnosed with multiple other autoimmune disorders. A family history of autoimmunity was present in 31 (31/151, 20.5%) patients, including 12 (12/151, 8.0%) with sarcoidosis. 110 patients (110/151, 72.8%) underwent some form of serologic testing, with 30 (30/151, 19.9%) testing positive. 23 (23/151, 15.2%) of these were not linked to a diagnosed non-sarcoidosis autoimmune disorder.

Comorbid autoimmune disorders and non-specific antibody seropositivity are common in neurosarcoidosis and represent potential opportunities for neuroinflammation misattribution and alteration of treatment selection and intensity.