IgE profiles of Bermuda grass pollen sensitised patients evaluated by Phleum pratense allergens Phl P 1, 2, 4, 5, 6 , 7, 11, 12.
BACKGROUND
Despite the difference in geographical dominance of certain grasses, a high degree of allergenic similarity or cross-reactivity between Bermuda grass pollen (BGP) and timothy grass pollen (TGP) has been previously demonstrated. The aim of the present study was to ascertain the sensitisation to TGP in 411 patients known for their reactivity to BGP extracts by analysing their reactivity to crude timothy pollen extract and timothy pollen purified allergens, establishing their specific IgE-profiles.


METHODS
Using the immunoenzymatic CAP method we evaluated IgE-specific antibodies for BGP- and TGP- extracts and the timothy recombinant (r) and natural (n) allergens rPhl p 1, rPhl p 2, nPhl p 4, rPhl p 5, rPhl p 6, rPhl p 7, rPhl p 11, and rPhl p 12.


RESULTS
BGP-IgE positive patients (median = 8.0 kUA/l, 2.8-22.2 kUA/l 25th-75th percentile) simultaneously had IgE positive results for TGP (100% of subjects)(median = 48.9 kUA/l, 19.8- > 100 kUA/l 25th-75th percentile) and high prevalence of sensitization to 6/8 Phleum pratense allergens (Phl p 1, 2, 4, 5, 6, 11, markers of genuine sensitisation to TGP) other than profilin and calcium binding protein. More than 72% of BGP allergic patients were co-sensitised to rPhl p 1, rPhl p 2, nPhl p 4, rPhl p 5, rPhl p 6. A decrease of total and specific IgE with patients' age was observed.


CONCLUSIONS
Our data show that all BGP-allergic patients simultaneously exhibit higher IgE antibody levels to recombinant and natural P. pratense allergens as well as to crude TGP extract. This suggests that when choosing an immunotherapeutic regimen for BGP-sensitised patients (after establishing their IgE profile via purified TGP-allergens), subcutaneous or sublingual TGP-extract vaccines in appropriate doses, in order to influence T epitope specificity, might be beneficial. Though extremely uncommon, in cases where a patient is exclusively BGP allergen-sensitised, BGP-extract therapy is the appropriate therapeutic response.
Rossi
Renato E
RE
Allergy Unit, National Health Service, Rete di Allergologia, Regione Piemonte, Ospedali di Fossano e Savigliano, Cuneo, Italy. immunoway@tin.it
Monasterolo
Giorgio
G
Prina
Paolo
P
Coco
Giuseppe
G
Operti
Daniela
D
Rossi
Lucilla
L
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D052179:Antigens, Plant / Q000276:immunology*; D001249:Asthma / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003233:Conjunctivitis, Allergic / Q000276:immunology; D003429:Cross Reactions; D031744:Cynodon / Q000276:immunology*; D003888:Desensitization, Immunologic; D006801:Humans; D007124:Immunoenzyme Techniques; D007073:Immunoglobulin E / Q000097:blood*; D008875:Middle Aged; D031784:Phleum / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D012189:Retrospective Studies; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology* / Q000628:therapy
D052179:Antigens, Plant; D011994:Recombinant Proteins; D007073:Immunoglobulin E