Common Blood Marker May Predict Response to Anti-IgE Therapy in Chronic Hives

A new study suggests that a simple blood test parameter may help predict which patients with chronic spontaneous urticaria (CSU) will achieve complete remission (CR) with omalizumab (Xolair; Genentech and Novartis) therapy.¹

CSU, commonly known as chronic hives, is a debilitating skin condition marked by recurrent wheals, itching, and sometimes angioedema lasting longer than 6 weeks without a clear trigger. The condition can significantly disrupt sleep, daily functioning, and quality of life. Although high-dose antihistamines are first-line therapy, many patients require biologic treatment with omalizumab, an anti-IgE monoclonal antibody approved for the condition in 2014.²

While omalizumab is highly effective for many individuals, approximately 30% to 40% of patients experience only partial improvement or fail to respond. Identifying reliable, accessible biomarkers that can forecast treatment success has therefore become a major clinical priority. Now, the new study, published in Cureus, suggests that baseline monocyte count can help identify those who will respond to treatment.

“The predictive value of monocytes is a relatively novel finding in the context of omalizumab treatment,” wrote the researchers of their findings. Because complete blood count testing is inexpensive and routinely available, baseline monocyte measurement could represent a practical tool for clinicians when counseling patients about expected treatment outcomes, highlighted the researchers, noting that identifying individuals most likely to achieve full remission could help optimize biologic use and reduce unnecessary healthcare costs.

The retrospective analysis was conducted at a tertiary dermatology center in Turkey, where researchers evaluated 52 patients with antihistamine-refractory CSU who received omalizumab 300 mg every 4 weeks for at least 12 weeks. Treatment response was assessed using the Urticaria Activity Score over seven days (UAS7), with CR strictly defined as a score of 0, indicating total symptom resolution.

At week 12, 11 patients (21.15%) achieved CR. When researchers compared laboratory markers between responders and non-responders, those who achieved CR had significantly higher median baseline monocyte levels (0.68 K/µL) compared to non-responders (0.40 K/µL), with strong statistical significance (P = .001). Importantly, binary logistic regression analysis confirmed that baseline monocyte count was the only independent predictor of complete response (P = .036).

In addition to elevated monocytes, complete responders also showed higher baseline basophil counts and lower C-reactive protein (CRP) levels, suggesting a distinct inflammatory profile.

The findings, explained the researchers, align with emerging evidence that CSU consists of at least 2 major immunologic endotypes: type I “autoallergic” and type IIb “autoimmune” disease. The type I form, thought to be more responsive to anti-IgE therapy, appears characterized by preserved basophils, lower systemic inflammation, and potentially higher monocyte involvement. In contrast, non-responders in the study exhibited lower baseline basophil counts and higher CRP levels, features more consistent with type IIb autoimmune CSU.

Monocytes are increasingly recognized as active contributors to CSU pathophysiology. Previous research has shown that monocytes in CSU patients may express high-affinity IgE receptors and contribute to vascular permeability and wheal formation. The higher baseline monocyte counts observed in complete responders may reflect an IgE-driven inflammatory pathway that is particularly susceptible to omalizumab’s mechanism of action.

Interestingly, in this new analysis, among patients who achieved CR, monocyte and neutrophil counts significantly decreased after treatment, suggesting that effective anti-IgE therapy may reduce broader inflammatory activity beyond mast cell stabilization.

Although total IgE levels increased in all patients following treatment, a known pharmacodynamic effect of omalizumab, baseline IgE levels did not significantly differ between responders and non-responders.

“While some studies suggest high baseline IgE predicts better response, our data indicate that the baseline serum IgE level alone may not be a sufficient discriminator for treatment outcome,” described the researchers.

The researchers noted several limitations of their study, including the retrospective design and relatively small sample size, which resulted in wide confidence intervals in regression analysis. Larger, prospective studies will be needed to validate specific monocyte thresholds and confirm these findings.

Reference

1. Turhan ID, Solak B. Baseline monocyte count predicts complete response to omalizumab in chronic spontaneous urticaria: a retrospective analysis. Cureus. 2026;18(1):e100557. doi:10.7759/cureus.100556

2. Genentech. FDA approves Xolair (omalizumab) for subcutaneous use for people with chronic idiopathic urticaria (CIU), a form of chronic hives. Published online March 21, 2014. Accessed February 17, 2026. https://www.gene.com/media/news-features/fda-approval-ciu