IgM and IgA in addition to IgG autoantibodies against FcɛRIα are frequent and associated with disease markers of chronic spontaneous urticaria.

Background: IgG autoantibodies against the high-affinity IgE receptor, FcɛRIα, contribute the pathogenesis of autoimmune chronic spontaneous urticaria (CSU). However, it is not known whether such patients also exhibit IgM or IgA autoantibodies against FcɛRIα. To address this question we developed an ELISA to assess serum levels of IgG, IgM, and IgA autoantibodies against FcɛRIα and investigated whether their presence is linked to clinical features of CSU including the response to autologous serum skin testing (ASST).

Biomarkers and clinical characteristics of autoimmune chronic spontaneous urticaria: Results of the PURIST Study.

Background: Autoimmune chronic spontaneous urticaria (aiCSU) is an important subtype of chronic spontaneous urticaria (CSU) in which functional IgG autoantibodies to IgE or its high-affinity receptor (FcεRI) induces mast cell degranulation and subsequent symptom development. However, it has not been tightly characterized. This study aimed to better define the clinical and immunological features and to explore potential biomarkers of aiCSU.