Autoimmune blistering diseases treated with glucocorticoids: An international study of steroid-induced myopathy.

BACKGROUND: Patients with autoimmune blistering diseases (AIBDs) are often exposed to chronic glucocorticoid (GC) treatment with many side effects. Glucocorticoid-induced myopathy (GIM) is a well-established side effect, which particularly affects the proximal muscles. The Glucocorticoid Toxicity Index (GTI) is a validated global assessment tool which quantifies GC toxicity over time. OBJECTIVES: This study marks the first study which analyses GIM in patients with AIBDs. The objectives of this study were to utilize the GTI to investigate the nature and prevalence of GIM in AIBD patients and explore potential risk factors. METHODS: This international cohort study was conducted in blistering disease clinics across Australia, China, Greece, Iran, Japan, the Philippines, Turkey and the United States of America between February 2019 and July 2023. The GTI tool was completed by a medical practitioner at each patient visit. Data related to glucocorticoid toxicity were entered into the Steritas GTI 2.0 to generate an aggregate improvement and cumulative worsening score at each visit. RESULTS: The study included 139 patients. There were 132 episodes of myopathy, and 47.5% of patients developed muscle weakness at some point during the study period. Cumulative GC dose correlated positively with myopathy risk, while average dose and treatment duration were not significant. Older age, male gender and obesity more than doubled the likelihood of developing GIM. CONCLUSIONS: GIM is a common side effect experienced by AIBD patients on GC treatment. Muscle weakness is less likely to occur if cumulative GC dose is less than 0.75 mg/kg/day. Studies of exercise programs to mitigate myopathy and newer alternative treatments to reduce cumulative GC dose should be considered.

Food allergen-mediated exacerbations of oral lichen planus.

Erosive oral lichen planus (OLP) is a chronic autoimmune condition of unknown aetiology, characterized by periods of exacerbation and quiescence. Many patients with OLP report triggers of flares that overlap with triggers of other oral diseases, including oral allergy syndrome (OAS), an IgE-mediated food allergy. We report a case that, to our knowledge, is the first reported case of concurrent OLP and OAS diagnoses, which provides insight into the triggers of OLP and the role of trigger avoidance. A woman in her 60s presented with erosive OLP refractory to prednisone and azathioprine. She reported that certain food exposures triggered flares of her OLP. She was subsequently diagnosed with concurrent OAS, and avoidance of food allergens resulted in a clinically significant improvement in her OLP, eventually allowing her to taper off systemic treatment altogether. Further studies are needed to pinpoint common triggers and examine the role of trigger avoidance as a management strategy for OLP.

E-cadherin autoantibody profile in patients with pemphigus vulgaris.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune skin blistering disease. The main targets of autoantibodies are the desmosomal proteins desmoglein (Dsg)3 and Dsg1. Anti-E-cadherin antibody is the second most frequent antibody found in pemphigus foliaceus (fogo selvagem), but the frequency in PV is unknown. OBJECTIVES: To determine the anti-E-cadherin antibody profile in the two major subtypes of PV: mucosal PV (mPV) and mucocutaneous PV (mcPV). METHODS: Sera from 80 patients with PV and 80 controls were tested. Patients with PV were subdivided into mPV (n = 18) and mcPV (n = 62). Samples were tested by E-cadherin, Dsg1 and Dsg3 enzyme-linked immunosorbent assays (ELISAs), and immunoprecipitation coupled with Western blotting (IP-WB). RESULTS: Both mPV and mcPV sera have antibodies against E-cadherin as demonstrated by ELISA and IP-WB. Both subtypes of PV have low levels of anti-E-cadherin antibodies, but significantly higher levels than healthy controls by ELISA (P < 0·0001). No difference exists in antibody levels between subgroups (P = 0·82). By IP-WB, 78% of mcPV sera reacted to E-cadherin, vs. 33% of mPV sera tested. Correlation analysis suggests a moderate correlation between anti-E-cadherin antibodies and Dsg1 antibodies (average r = 0·61), but no correlation with Dsg3 antibodies (average r = 0·19). Patients with mPV can have lower levels of Dsg1 antibodies compared with controls by ELISA (P < 0·0001). A few mPV sera also reacted to Dsg1 protein by IP-WB (17%). CONCLUSIONS: Anti-E-cadherin antibodies are present in both major subtypes of PV. A moderate correlation exists between E-cadherin and Dsg1 antibodies. Patients with mPV can have low levels of both E-cadherin and Dsg1 antibodies.