BACKGROUND: Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances has not been investigated to date. OBJECTIVE: To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE < 3 kDa) on the human allergic immune response in vivo. METHODS: Birch and grass pollen allergic individuals underwent skin prick testing with allergen alone, allergen plus Bet-APE < 3 kDa, or allergen plus pre-identified candidate substances from low molecular pollen fraction. Nasal allergen challenges were performed in non-atopic and pollen allergic individuals using a 3 day repeated threshold challenge battery. Subjects were either exposed to allergen alone or to allergen plus Bet-APE< 3 kDa. Local cytokine levels, nasal secretion weights, nasal congestion and symptom scores were determined. RESULTS: Skin prick test reactions to pollen elicited larger weals when allergens were tested together with the low molecular weight compounds from pollen. Similar results were obtained with candidate pollen-associated lipid mediators. In nasal lining fluids of allergic patients challenged with allergen plus Bet-APE < 3 kDa, IL-8 and IgE was significantly increased as compared to allergen-only challenged patients. These patients also produced increased amounts of total nasal secretion and reported more severe rhinorrhea than the allergen-only challenged group. CONCLUSIONS: Low molecular compounds from pollen enhance the allergen specific immune response in the skin and nose. They are therefore of potential clinical relevance in allergic patients.
- Gilles-Stein, S.
- Beck, I.
- Chaker, A.
- Bas, M.
- McIntyre, M.
- Cifuentes, L.
- Petersen, A.
- Gutermuth, J.
- Schmidt-Weber, C.
- Behrendt, H.
- Traidl-Hoffmann, C.
Keywords
- Allergens/*immunology
- Basophils/immunology/metabolism
- Betula/immunology
- Cell Degranulation/immunology
- Humans
- *Immunity
- Immunoglobulin E/blood/immunology
- *Immunomodulation
- Inflammation Mediators/metabolism
- Interleukin-8/metabolism
- Molecular Weight
- Nasal Mucosa/immunology/metabolism
- Nasal Provocation Tests
- Plant Extracts/chemistry/*immunology
- Pollen/chemistry/*immunology
- Rhinitis, Allergic, Seasonal/diagnosis/*immunology/metabolism
- Skin Tests
- Symptom Assessment
- Th2 Cells/immunology/metabolism
- *low molecular weight pollen fraction
- *nasal challenge
- *pollen-associated lipid mediator
- *prick test