New markers to predict the response to omalizumab in chronic spontaneous urticaria

Omalizumab has high treatment efficacy in patients with chronic spontaneous urticaria (CSU) who do not respond to high doses of antihistamines. Systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) were described as novel inflammatory and prognostic biomarkers. The present study aimed to evaluate the effectiveness of SII and SIRI in patients with CSU who receive omalizumab therapy. A total of 124 patients with severe urticaria who had an urticaria activity score over 7 days (UAS-7) ≥28 were included in the study. UAS-7, C-reactive protein (CRP), SII, and SIRI values ​​were recorded before and after omalizumab treatment. Patients with UAS-7 ≤6 at week 12 and/or week 24 of omalizumab treatment were considered responders. Three months after omalizumab treatment, significant decreases were observed in SII, SIRI, CRP, and UAS-7 compared to pre-treatment values ​​(p = 0.003, p < 0.001, p = 0.006, and p < 0.001, respectively). At the third and sixth months of treatment, baseline SII and SIRI levels of the omalizumab responder group were significantly higher than the non-responder group (p < 0.001). However, there was no difference in baseline CRP and UAS-7 levels between responders and non-responders (p ˃ 0.05). After adjusting for confounding factors, only pre-treatment SII (OR: 1.002, 95% CI: 1.000-1.004, p = 0.036) and SIRI (OR: 4.334, 95% CI: 1.751-10.726, p = 0.002) values were independently associated with response to omalizumab at 3 months in multivariate regression analysis. SII and SIRI could be effectively used to predict the response to omalizumab therapy. More comprehensive studies are needed to validate and elaborate on this relationship.