Type I and type IIb autoimmune chronic spontaneous urticaria: Using common clinical tools for endotyping patients with CSU

• Published in: The journal of allergy and clinical immunology. Global 2023-11, Vol.2 (4), p.100159-100159, Article 100159
• Main Authors: Sella, Juliana A., Ferriani, Mariana P.L., Melo, Janaina M.L., Trevisan Neto, Orlando, Zanetti, Maria Eduarda T., Cordeiro, Daniel L., Lemos, José E., Barros, Sebastião A., Aragon, Davi C., Arruda, L. Karla
• Format: Article
• Language: English
• Subjects: autoimmunity; chronic spontaneous urticaria; IgE; omalizumab; Urticaria
• ISSN: 2772-8293; 2772-8293
• DOI: 10.1016/j.jacig.2023.100159

BackgroundMechanisms triggering the pathogenesis of chronic spontaneous urticaria (CSU) have been identified as type I autoallergic (which is associated with IgE antibodies against autoantigens) and type IIb autoimmune (which is driven by autoantibodies to FceR1 and/or IgE). ObjectiveOur aim was to define presumptive endotypes in patients with CSU by using tests amenable to use in routine clinical practice. MethodsA retrospective analysis of the medical records of 394 patients with CSU with or without chronic inducible urticaria or angioedema was performed. Patients were assigned to 1 of 4 groups as follows: (1) type I endotype of CSU, if they presented at least 1 of the following: allergic disease, total IgE level of at least 40UI/mL, and positive result of skin tests to inhalant allergen(s), (2) type IIb endotype of CSU, if they presented at least 1 of following: autoimmune disease, low total IgE level less than 40 IU/mL, positive autologous serum skin test result, positive for antinuclear antibodies in a titer of at least 1:160, and elevated level of anti-thyroid peroxidase, (3) overlap of type I/type IIb endotypes of CSU, if they presented with at least 1 marker of both type I and type IIb, and (4) non-type I/type IIb endotype of CSU, if they presented with none of the markers of type I or type IIb. ResultsThe mean age at onset of symptoms was 34 years; 82.2% of those with CSU were female, and angioedema and chronic inducible urticaria were found in 74.8% and 31.9% of patients, respectively. Of the patients with CSU, 38% presented with the type I endotype and 51% presented with type I/type IIb overlap, whereas 9% presented with the type IIb endotype and 2% presented with the non-type I/type IIb endotype. Eosinopenia was associated with type IIb and type I/type IIb overlap as opposed to the type I and non-type I/type IIb endotypes (P = .02). ConclusionsMost patients with CSU presented with features of the type 1 (autoallergic) endotype, whether associated with type IIb (autoimmune) endotype or not.