Altrichter S, Zampeli V, Ellrich A, Zhang K, Church MK, Maurer M.
Allergy. 2020 May 23. doi: 10.1111/all.14412. Online ahead of print.
Chronic spontaneous urticaria (CSU) is a mast cell–driven skin disease characterized by the recurrence of transient wheals, angioedema, or both for more than 6 weeks. IgG-autoantibodies against the high affinity IgE-receptor, FcεRIα, contribute to the pathogenesis of autoimmune chronic spontaneous urticaria.
The objective of this study was to develop an ELISA to assess serum levels of IgG, IgM and IgA autoantibodies against FcεRIα and to explore if their presence is linked to clinical features of CSU including the response to autologous serum skin testing (ASST).
Serum samples of 35 people with CSU and 52 healthy controls were tested using an ELISA for IgG, IgM and IgA autoantibodies to FcεRIα. 24 % of CSU patients had high serum levels of IgG-anti-FcεRIα compared to 6 % in healthy controls. IgM and IgA levels were positive for more than half of people with CSU, compared to 5 % in healthy controls. Elevated IgM, but not IgG nor IgA autoantibodies, were significantly more common in ASST-positive CSU patients (72 %) compared with ASST-negative patients (33 %). Also, elevated levels of IgM-anti-FcεRIα, but not of IgG or IgA against FcεRIα, were linked to low blood basophil and eosinophil counts.
In conclusion, people with CSU have increased serum levels of IgM-anti-FcεRIα which may relate to characteristics of autoimmune CSU.