Distribution of specific serum IgE to recombinant pollen allergens (rPhlp1, rPhlp2, rPhlp5, and rBetv2) and their relationship to each other and to their natural counterparts in patients allergic to grass pollen

Recombinant pollen allergens rPhlp1, rPhlp2, rPhlp5, and rBetv2 may function as effective markers of atopy and account for a substantial proportion of grass pollen-specific IgE. The purpose of the present study was to determine the frequency of IgE antibodies to rPhlp1, rPhlp2, rPhlp5 and rBetv2 in patients allergic to grass pollen. Blood was taken from 436 patients, aged 4-70 years, with allergy to grass. The sample was stratified by 10-year age groups. Specific serum IgE were measured by the immunoenzymatic CAP Fluoroenzyme Immunoassay System. Specific IgE binding to rPhlp1, rPhlp5, rPhlp2, was, respectively, detected in 388 (88.9%), 353 (80.9%) and 265 (60.7%) of 436 patients. Sera from 252 patients (57.7%) showed IgE binding to rPhlp1, rPhlp2 and rPhlp5; sera from 102 patients (23.3%) reacted to rPhlp1 and rPhlp5, but not rPhlp2; 30 sera (6.8%) reacted to rPhlp1 but not rPhlp2 and rPhlp5; 22 sera (5.1%) reacted only to rPhlp5; one serum reacted to rPhlp2 (0.2%); and nine sera (2%) did not react to recombinant allergens. It was found that patients in the age group 0-20 years had higher IgE levels to timothy grass and rPhlp1, rPhlp2 and rPhlp5, than patients in the older age group (41-60 years). We found, as expected, seasonal variation of IgE levels to recombinant allergens and natural allergen. Allergens rPhlp1, rPhlp2 and rPhlp5 were extremely positively correlated with timothy grass and rBetv2, but not rBetv1. These results encourage the use of recombinant pollen allergens for diagnosis and to improve specific immunotherapy in the near future