Autoimmune Chronic Spontaneous Urticaria Detection with IgG Anti-TPO and Total IgE

Abstract

Background: Autoimmune chronic spontaneous urticaria (aiCSU) comes with high disease activity and poor response to treatment. Recently, elevated levels of IgG anti-thyroid peroxidase (aTPO) and low levels of total IgE were reported to be common in aiCSU.

Objective: To investigate how high aTPO and low IgE individually and combined are linked to features of aiCSU, including treatment responses.

Methods: We analyzed records of patients with CSU from 2 independent cohorts (n = 1120) for demographic, clinical, and laboratory parameters and treatment responses. Total IgE and aTPO were measured, and 4 markers of aiCSU were analyzed: autologous serum skin test, basophil activation test (BAT), and blood eosinophil and basophil counts. Cutoff values were greater than or equal to 34 kU/L (high aTPO) and less than 40 IU/mL (low total IgE).

Results: One of 10 patients with CSU had both high aTPO and low IgE (aTPO↑IgE↓, 11%, n = 123). aTPO↑IgE↓ was linked to higher age at CSU onset, being female, angioedema, and shorter CSU duration. aTPO↑IgE↓ was associated with markers of aiCSU, that is, BAT and autologous serum skin test positivity, basopenia, and eosinopenia (P < .01 for all). Almost half the patients with aTPO↑IgE↓ (44%, 19 of 43) had a positive BAT result, the best single marker for aiCSU, versus 12% (43 of 344) of patients without aTPO↑IgE↓ (P < .001). Relative risk of showing BAT positivity for a patient with aTPO↑IgE↓ is 3.636 (95% CI, 2.382-5.551). Patients with aTPO↑IgE↓ showed low response rates to antihistamine treatment as compared with patients without aTPO↑IgE↓ (30% vs 47%; P = .01).

Conclusions: Our findings suggest that aTPO↑IgE↓ is a useful diagnostic marker for aiCSU in everyday clinical practice.

Keywords: Antihistamines; Autoimmune chronic spontaneous urticaria; Basophil activation test; IgG anti-TPO; Marker; Thyroid peroxidase; Total IgE.