Neuroinflammation Associated With Tumor Necrosis Factor-α Inhibitor Exposure

To identify the frequency and clinical spectrum of neuroinflammation associated with exposure to tumor necrosis factor-α inhibitors (TNFi).

We performed a single-system retrospective cohort study. Adults in the Yale New Haven Health System with documented use of any US Food and Drug Administration-approved TNFi between 2007 and 2017 were identified via automated review of the electronic medical record. Those who also had brain MRIs were identified and categorized as either TNFi exposed or unexposed. Individuals with MRI findings concerning for neuroinflammation were identified, and detailed chart reviews were performed.

A total of 4,391 patients received TNFi, and 547 also had brain MRI. After exclusion criteria were applied, 375 MRIs occurred after TNFi exposure, and 132 MRIs occurred before TNFi. MRIs were normal for 20.8% of exposed patients. The most common abnormal finding was nonspecific, punctate T2 hyperintensities. Seventeen cases (4.5%) among the exposed cohort had findings consistent with neuroinflammation, of which 58.8% required TNFi discontinuation and additional immunotherapy, whereas an additional 23.5% discontinued TNFi alone. After 3 years, 70.6% had stable MRI findings, whereas 11.8% demonstrated progression. The 10-year period prevalence of neuroinflammation in all subjects exposed to TNFi was 0.4%.

Neuroinflammatory phenomena following TNFi are a common concern for those treating patients with autoimmune disease. This is a large-scale study identifying the epidemiology surrounding this phenomenon. TNFi-associated inflammation was a rare outcome in our cohort. Most treated patients had either normal or nonspecific MRI findings. Further risk stratification parameters need to be identified.