New light on an old syndrome: Role of Api g 7 in mugwort pollen–related celery allergy

• Published in: Journal of allergy and clinical immunology Vol. 154; no. 3; pp. 679 - 689.e5
• Main Authors: Ballmer-Weber, Barbara K., Wangorsch, Andrea, Bures, Peter, Hanschmann, Kay-Martin, Gadermaier, Gabriele, Mattsson, Lars, Mills, Clare E.N., van Ree, Ronald, Lidholm, Jonas, Vieths, Stefan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2024
• Subjects: Adolescent; Adult; Aged; Allergens - immunology; Anaphylaxis - diagnosis; Anaphylaxis - etiology; Anaphylaxis - immunology; Antigens, Plant - immunology; Apium - adverse effects; Apium - immunology; Artemisia - immunology; birch pollen; celeriac; celery root; Child; Component-resolved diagnosis; cross-reactivity; defensin-like protein 1; Female; food challenge; Food Hypersensitivity - diagnosis; Food Hypersensitivity - immunology; Humans; Immunoglobulin E - blood; Immunoglobulin E - immunology; Male; Middle Aged; mugwort pollen; Plant Proteins - immunology; Pollen - immunology; pollen food syndrome; Rhinitis, Allergic, Seasonal - diagnosis; Rhinitis, Allergic, Seasonal - immunology; Syndrome; threshold dose; Young Adult; nsLTP; defensin-like protein 1; pollen food syndrome; OR; CCD; CI; threshold dose; mugwort pollen; Api g; LTP; cross-reactivity; Component-resolved diagnosis; celeriac; Art v; birch pollen; food challenge; CRD; Bet v; LOAEL; celery root; ED10; Pru p
• ISSN: 0091-6749; 1097-6825; 1097-6825
• DOI: 10.1016/j.jaci.2024.04.030

[Display omitted] Celery root is known to cause severe allergic reactions in patients sensitized to mugwort pollen. We studied clinically well-characterized patients with celery allergy by IgE testing with a comprehensive panel of celery allergens to disentangle the molecular basis of what is known as the celery–mugwort syndrome. Patients with suspected food allergy to celery underwent a standardized interview. Main inclusion criteria were a positive food challenge with celery or an unambiguous case history of severe anaphylaxis. IgE to celery allergens (rApi g 1.01, rApi g 1.02, rApi g 2, rApi g 4, nApi g 5, rApi g 6, rApi g 7) and to mugwort allergens (rArt v 1, rArt v 3, rArt v 4) were determined. IgE levels ≥0.35 kUA/L were regarded positive. Seventy-nine patients with allergy to celery were included. Thirty patients had mild oral or rhinoconjunctival symptoms, and 49 had systemic reactions. Sixty-eight percent had IgE to celery extract, 80% to birch pollen, and 77% to mugwort pollen. A combination of Api g 1.01, 1.02, 4, 5, and 7 increased the diagnostic sensitivity for celery allergy to 92%. The lipid transfer proteins Api g 2 and Api g 6 were not relevant in our celery-allergic population. IgE to Api g 7, detected in 52% of patients, correlated closely (r = 0.86) to Art v 1 from mugwort pollen. Eleven of 12 patients with monosensitization to Api g 7 were IgE negative to celery extract. The odds ratio for developing a severe anaphylactic reaction rather than only mild oral symptoms was about 6 times greater (odds ratio, 5.87; 95% confidence interval, 1.08-32.0; P = .0410) for Api g 7–sensitized versus –nonsensitized subjects. There is an urgent need for routine diagnostic tests to assess sensitization to Api g 7, not only to increase test sensitivity but also to identify patients at risk of a severe allergic reaction to celery.