NDM03
Prevalence of Iatrogenic Central Nervous System Inflammation at a Tertiary Neuroimmunology Clinic
Increased utilization of biologics to treat autoimmune diseases and cancer has coincided with a rise in iatrogenic central nervous system (CNS) inflammation. Tumor-necrosis-factor-alpha inhibitors (TNFAIs), immune-checkpoint inhibitors (ICIs), and other immunomodulators have been linked to inflammatory CNS events. Furthermore, various vaccines have been implicated in rare demyelinating events.
Objectives:
We aim to determine the prevalence and clinical characteristics of iatrogenic CNS inflammation associated with various biologics and vaccinations at a tertiary neuroimmunology clinic.
Methods:
We analyzed consecutive adult patients seen over five years (1/2017-12/2021) at a tertiary neuroimmunology referral clinic who were systematically screened for iatrogenic demyelinating and inflammatory events secondary to TNFAIs, ICIs, and/or vaccines. In patients with suspected iatrogenic events, the Naranjo Adverse Drug Reaction Probability Scale was used to score the probability of drug- or vaccine-induced adverse events as doubtful, possible, probable, or definite.
Results:
In total, 422 adult patients were analyzed and 27 potential iatrogenic events were observed, accounting for 6.4% of new referrals. The average Naranjo score was 5.78 +/- 1.65 with 74% of cases scored as probable and 26% as possible. The clinical phenotypes included MS relapses (37%); autoimmune encephalitis (30%); neuromyelitis optica spectrum disorder (NMOSD) attacks (15%); transverse myelitis (11%); optic neuritis (4%); and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) attacks (4%). A monophasic course was observed in 44% of cases while 41% were relapsing. Also, 41% of events were fully-responsive to corticosteroids. The most common potential triggers were vaccines (37%) followed by TNFAIs (33%) then ICIs (26%). A higher number of probable events were observed among the ICI and vaccine groups compared to more possible events among the TNFAI group. The latter group also had a longer interval since exposure. Finally, the ICI group was more likely to present with monophasic autoimmune encephalitis.
Conclusions:
Iatrogenic CNS inflammation is rare and typically involves steroid-responsive monophasic events. A subset of events can unmask or worsen relapsing disorders. A variety of vaccines and immunomodulating agents are implicated in iatrogenic CNS inflammation. The probability of iatrogenicity was higher in vaccine and ICI-related events compared to TNFAI-related events.