Omalizumab-treated participants showed significant decreases in IL-4⁺peanut-reactive CD4⁺ T cells and plasmacytoid dendritic cells

MILWAUKEE, Feb. 23, 2026 /PRNewswire/ -- Omalizumab, both as a monotherapy and for oral immunotherapy (OIT), modulates specific T cell and dendritic cell (DC) subsets, increasing patient's reaction thresholds to common food allergens, according to new research being presented at the 2026 AAAAI Annual Meeting.

"Our mechanistic studies using blood samples from participants in the OUtMATCH trial show, for the first time, that there are major differences in how omalizumab alone, without OIT compared to omalizumab with multi OIT, works to modify the immune system in a transient vs permanent way, respectively," said lead author Kari C. Nadeau, MD, PhD, FAAAAI, and co-author Sharon Chinthrajah, MD, FAAAAI.

This research provides valuable insight into the downstream effects of omalizumab on immune cells, providing allergist/immunologists additional means to monitor patient outcomes.

In the OUtMATCH trial, participants received 16-20 weeks of Stage 1 treatment of either omalizumab or a placebo. In Stage 2, participants first received 8 weeks of omalizumab followed by 52 weeks of omalizumab plus placebo OIT or omalizumab-facilitated OIT, receiving omalizumab for the first eight weeks. High-dimensional spectral flow cytometry was used to profile T cell and DC subsets in peripheral blood mononuclear cells (PBMCs) collected at the baseline and the end of Stages 1 and 2.

After Stage 1, omalizumab-treated participants showed significant decreases in IL-4⁺peanut-reactive CD4⁺ T cells, IL-4⁺CD4⁺T cells and Fcepsilon;RI⁺ myeloid and plasmacytoid DCs compared to the baseline, with no such changes in the placebo group. After Stage 2, both treatments reduced IL-4⁺peanut-reactive and IL-4⁺CD4⁺T cells; Fcepsilon;RI⁺mDCs/pDCs decreased only in the omalizumab plus placebo OIT group, while OX40L⁺mDCs/pDCs decreased only in the omalizumab-facilitated OIT group. Researchers found that, after Stage 1, participants passing the 600 mg peanut challenge had lower IL-4⁺peanut-reactive T cell frequencies than those who failed. After Stage 2, in the omalizumab plus placebo OIT group, higher mDC/pDC frequencies in peanut-stimulated cultures were observed by researchers for those passing the 2000 mg challenge compared to those who failed.

Visit aaaai.org to learn more about food allergies. Research presented at the 2026 AAAAI Annual Meeting, February 27 – March 2 in Philadelphia, PA, is published in an online supplement to The Journal of Allergy and Clinical Immunology (JACI).

The American Academy of Allergy, Asthma & Immunology (AAAAI) is the leading membership organization of more than 7,100 allergists, asthma specialists, clinical immunologists and other professionals with a special interest in the research and treatment of allergic and immunologic diseases. Established in 1943, the AAAAI is the go-to resource for patients living with allergies, asthma and immune deficiency disorders.

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SOURCE American Academy of Allergy, Asthma & Immunology (AAAAI)