Autoimmune screening panel in patients with multiple sclerosis: A Vienna multiple sclerosis database study.

Background And Purpose: Autoimmune screening panels (ASPs) are often ordered as a part of the diagnostic workup in people with suspected multiple sclerosis (MS). However, data on the significance of ASP seropositivity in MS are scarce. This study aimed to investigate whether routine implementation of ASPs is viable in MS diagnostic workup.

Methods: In this retrospective study, we included patients from the Vienna Multiple Sclerosis Database who were diagnosed with MS according to current McDonald criteria between 2014 and 2021 and had an ASP performed.

Results: We analyzed 212 patients (mean age at serology = 30.4 [SD = 8.5] years, 67% female). Red flag symptoms for presence of systemic autoimmune disease were reported by 5.6% of patients during initial evaluation (sicca syndrome [n = 5], joint pain [n = 4], dermatitis [n = 4]). Complement levels (C3c and C4) were below the lower reference level in 26 of 134 (19.4%) and three of 134 (2.2%), respectively. Antinuclear antibodies (ANAs) were positive in 24 of 210 (11.4%), with 18 (8.6%), five (2.4%), and one (0.5%) having mildly, moderately, and strongly positive ANA titers. Extractable nuclear antibody subsets were positive in 10 of 211 (4.7%) patients. ASPs led to the diagnosis of mixed connective tissue disease (n = 1), psoriatic arthritis (n = 1), and Sjögren syndrome (n = 2; positive predictive value [PPV] = 4.9%, negative predictive value [NPV] = 99.3%). Among patients presenting with red flag symptoms, ASPs had better overall test performance (PPV = 100%, NPV = 88.9%).

Conclusions: The rate of ASP seropositivity in MS is low and within the range of the general population. Performance of ASPs without clinical suspicion of systemic autoimmune disease seems unwarranted.