Pavel Kolkhir, Elena Kovalkova, Anton Chernov, Inna Danilycheva, Karoline Krause, Merle Sauer, Andrey Shulzhenko, Daria Fomina, Marcus Maurer
J Allergy Clin Immunol Pract . 2021 Aug 4;S2213-2198(21)00884-9. doi: 10.1016/j.jaip.2021.07.043. Online ahead of print.
Common spontaneous urticaria (CSU) is a common skin condition driven by mast cells and characterized by the development of wheals, angioedema, or both for more than six weeks. Recently, studies have demonstrated the existence of two endotypes on the pathogenesis of CSU: type I (“autoallergic”) and type IIb autoimmune CSU.
Type IIb autoimmune CSU (aiCSU) is related to IgG, IgM, and IgA autoantibodies against the high affinity IgE receptor, FcɛRIα, activating skin mast cells. At least 8% of the CSU cases are aiCSU and represent a high disease burden (high disease activity, high rates of autoimmune comorbidity, and inadequate response to treatment). aiCSU can be challenging to diagnose because the existing tests (autologous serum skin test (ASST), autoantibody immunoassays, and basophil testing) are not usually available and have limitations. Also, aiCSU responds poorly to treatment.
This study aimed to evaluate how high anti-thyroid peroxidase (aTPO) and low IgE relate to aiCSU and treatment response.
A total of 1120 patient records were analyzed for demographic, clinical, laboratory parameters and treatment responses. Total IgE and aTPO were measured, and four markers were analyzed (ASST, basophil activation test (BAT), eosinophil, and basophil counts).
One of ten patients (n=123) had both high aTPO and low IgE, which was linked to higher age at CSU onset, female, angioedema, and shorter CSU duration. It was also related to positivity to aiCSU markers. A positive BAT was present in 44% of the patients with high aTPO and low IgE. These patients had low response rates to antihistamine treatment compared to the remaining patients.
In conclusion, a high aTPO and low IgE may constitute a valuable biomarker for diagnosing aiCSU in daily clinical practice.
