Sabine Altrichter, Germany
Charité – Universitätsmedizin Berlin Dermatological Allergology, Allergie-Centrum-Charité, Department of Dermatology and AllergyPresenter of 1 Presentation
AUTOANTIBODIES AGAINST FCERIΑ OF DIFFERENT SUBCLASSES ARE FREQUENT AND ASSOCIATED WITH FEATURES OF CHRONIC SPONTANEOUS URTICARIA
Abstract
Background and Aims
IgG-autoantibodies against the high affinity IgE-receptor, FceRIα, are thought to be key features of type IIb autoimmune chronic spontaneous urticaria (CSU). However, it is not known, if in CSU also IgM or IgA autoantibodies against FceRIα exist. The aim was to develop an ELISA to assess serum levels of IgG, IgM and IgA autoantibodies against FceRIα, and to investigate their link to clinical features of CSU.
Methods
We analyzed serum samples of 35 patients with CSU (25 ASST-positive) and 52 healthy controls using a competitive ELISA for determination of IgG, IgM and IgA autoantibodies to FceRIα.
Results
One in four CSU patients (24%) exhibited elevated serum levels of IgG-anti-FceRIα. More than half of the CSU patients had IgM (60%) and IgA (57%) vs 5% each in healthy controls. ASST-positive patients showed most frequent elevated levels of IgM class autoantibodies (72% in ASST pos vs. 30% in ASST neg; P = 0.022). No association was seen with IgG or IgA autoantibodies. Also, elevated levels of IgM-anti-FceRIα, but not of IgG or IgA against FceRIα, were linked to low blood basophil (r = 0.414, P = 0.021) and eosinophil (r = 0.623, P < 0.001) counts, features of high disease activity in CSU.
Conclusions
Our novel assay can detect IgG, IgM and IgA autoantibodies against FceRIα. Increased serum levels of IgM-anti-FceRIα are very common in patients with CSU and showed a link to features of autoimmune CSU. The role and relevance of autoantibodies to FceRIα in CSU should be further characterized in future studies.