Antinuclear antibodies in postinfectious smell loss - a pilot study

Background: Numerous diseases are mediated by autoimmune mechanisms some of which have been shown to be associated with reduced olfactory function, e.g. systemic lupus erythematosus, Sjögren syndrome, psoriasis vulgaris. Postinfectious smell loss is a frequent cause of olfactory dysfunction. However, its nature is not fully understood, but connections to immune mediated processes might be possible. The primary aim of the present study was therefore to investigate the possible relation of postinfectious smell loss with autoimmune processes. Methods: Fifty-two patients (35 female, 17 male; mean age 57 years ± 12 years) with postinfectious smell loss and 56 controls (21 female, 35 male; mean age 58 years ± 13 years), with olfactory dysfunction of other causes (sinunasal, posttraumatic or idiopathic) were included in the present study. The patients’ olfactory function was measured using the extended test battery of the "Sniffin’ Sticks“. Furthermore venous blood samples were taken and analyzed for antinuclear autoantibodies. Results: Patients showed anti-nuclear antibodies (ANA) significantly more frequently compared to controls, although ANAs were typically only present at cut off levels of 1:100. In addition, there was a significant association between the presence of ANAs and odor thresholds. Conclusions: Results from this study indicate that postinfectious olfactory dysfunction may be associated with autoimmune processes, as they show significantly more ANAs – although not at a clincially significant level compared to patients with olfactory deficits of other origin.