Effect of confounding cofactors on responses to pollens during natural season versus pollen challenge chamber exposure

• Published in: Journal of allergy and clinical immunology Vol. 133; no. 5; pp. 1340 - 1346.e7
• Main Authors: Jacobs, Robert L., MD, Harper, Nathan, BS, He, Weijing, MD, Andrews, Charles P., MD, Rather, Cynthia G., CCRC, Ramirez, Daniel A., MD, Ahuja, Sunil K., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.05.2014; Elsevier; Elsevier Limited
• Subjects: Adolescent; Adult; Aged; Allergies; Allergy; Allergy and Immunology; Ambrosia; Biological and medical sciences; Calendars; challenge; confounding; Conjunctivitis, Allergic - immunology; Conjunctivitis, Allergic - pathology; Conjunctivitis, Allergic - therapy; Desensitization, Immunologic; Diaries; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunopathology; Likert scale; Male; Medical sciences; Middle Aged; Mold; Plant reproduction; Pollen; Pollen - immunology; Quercus; Rhinitis, Allergic, Seasonal - immunology; Rhinitis, Allergic, Seasonal - pathology; Rhinitis, Allergic, Seasonal - therapy; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; season; Seasons; Studies; Time Factors; Texas; Virginia live oak; Allergy; confounding; pollen; Allergic rhinoconjunctivitis; Pollen challenge chamber; Total symptom score; AR; PCC; TSS; MC; Mountain cedar; VLO; challenge; season; Immunopathology; Immunology; Exposure; Pollen; Season; Confounding factor; Cofactor; Comparative study
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2013.09.051

Background The severity of allergic rhinoconjunctivitis (AR) symptomatology elicited after exposure to pollen in the absence versus the presence of confounding cofactors, such as in a pollen challenge chamber (PCC) and the natural pollinating season, respectively, might differ. Objective We sought to determine the correlation of AR severity in the natural season versus out-of-season PCC exposures. Methods Twenty-four Virginia live oak (VLO)–positive, 14 VLO-negative, 16 mountain cedar (MC)−positive, 8 MC-negative, and 26 ragweed-positive participants recorded AR symptoms (total symptom score [TSS]) during the VLO, MC, and ragweed pollinating seasons and during 2 consecutive PCC exposures of 3 hours each to these pollens separately. Results The TSSs recorded before the natural season were higher than the pre-PCC values. This prepriming was greater among VLO+ than MC+ participants, and it blunted further increases in TSSs during the VLO natural season. Nonatopic participants were nonreactive in the PCC. There was wide variation in the level of AR symptomatology after exposure to VLO, MC, or ragweed pollen in the PCC. Prepriming formed the basis for higher AR responses observed in the natural season than in the PCC, resulting in the identification of distinct PCC/natural season endophenotypes and a partial correlation between the TSSs recorded in the natural season versus those recorded in the PCC ( r  = 0.34, 0.54, and 0.65 for VLO+ , MC+ , and ragweed-positive participants, respectively). Conclusions Prepriming in the natural pollinating season might obscure the true correlation between AR severity in the natural season versus the PCC. By mitigating confounding cofactors, PCC exposures have utility for evaluation of novel AR therapeutics.