Single pollen-sensitization
In total, 4234 patients were enrolled (Table 2). The comparison of the sensitization against extracts and the respective major allergens is shown in Table 3.
Grass: We found 1984 patients with IgE-measurements to timothy grass extract and Phl p 1+5. Median age was 26.9 years (1.2-89.7 years). While 1745 displayed IgE for timothy grass extract, 1658 were positive for Phl p 1+5. 94.3% of extract positive patients tested positive for the major allergen, 11.4% of all patients were negative for both measurements. Twelve patients (=5% of all extract-negative patients) with a negative extract result were positive for Phl p 1,5. This observation was clinically relevant for 6 patients (2.5%) in which AIT was recommended despite negative extract results. Ninety-nine patients (=5.7% of all extract positive patients) were extract-positive, but Phl p 1+5-negative. This observation was clinically relevant for 18 (1%) of these patients, as the treating physicians advised against AIT.
There was a strong correlation between timothy-grass extract and Phl p 1+5 (PCC 0.87, p<0.01; Fig. 1A) and a very high agreement (94.4%) between extract and major-allergen results (Table 3).
Birch: Parallel analyses of sensitization to birch extract and Bet v 1 were available for 1555 patients. Median age was 31.3 years (2.7-89.7 yrs). While 1350 patients had a positive IgE result for birch extract, 1279 were positive for Bet v 1. In summary, 94.1% of extract positive patients were also positive for the major allergen, while 12.7% of all patients were negative for both measurements. Eight patients (3.9%) with a negative result for the extract tested positive to Bet v 1, of whom 5 had an IgE <0.69 kUA/l. In the other 3 patients (1.5%), AIT was recommended based on a positive major allergen value. Seventy-nine (5.9%) of extract positive patients showed negative results in Bet v 1. In only one patient AIT was performed and this showed no clinical benefit. In 14 patients (1% of all birch extract positive tests) the physicians advised against AIT because of the negative Bet v 1 result.
There was a strong correlation between birch extract and Bet v 1 (PCC 0.82, p<0.01; Fig. 1B) and a very good agreement (94.4%) between extract and major-allergen results (Table 3).
Ash-tree: One hundred and eighty-one patients could be included with parallel measurements of ash-tree extract and Ole e 1. The patients´ median age was 27 years (3.8-65.5 yrs). One hundred and fifty-seven patients tested positive for the extract, 128 for the major allergen. While 80.9% of extract positive patients were also positive for the major allergen, 12.7% of all patients were negative for both measurements. Only 1 patient was positive for Ole e 1 (with a value of 1.09 kUA/l) while testing negative for the extract. On the other hand, 19.1% of patients were extract positive and Ole e 1 negative. AIT wasn’t recommended for any of these patients, and in 2 (1.3%) patients AIT was specifically advised against due to the results. Half of these 30 Ole e 1 negative, extract positive patients suffered from birch pollen allergy, and AIT against birch was recommended or had already begun.
There was a strong correlation between ash extract and Ole e 1 (PCC 0.94, p<0.01; Fig. 1C) and a high agreement (82.9%) between extract and major-allergen results (Table 3).
Mugwort : Over the study period, 262 patients were included with results for both mugwort extract and Art v 1. The patients´ median age was 31.2 (5-73 yrs). One hundred and ninety-nine patients had a positive result for the extract, while 109 were positive for the major allergen. 53.8% of extract positive patients were also positive for Art v 1, while 23.3% of all patients were negative for both measurements. Two patients (3.2%) with a negative result for the extract tested positive for Art v 1. Ninety-two (46.2%) extract positive patients showed negative results for Art v 1. Only one of these patients received AIT against mugwort, in 6 patients AIT was definitely advised against in the patient chart, while in 38 (41.3%) a ragweed-allergy was detected and AIT against ragweed recommended.
There was a strong correlation between mugwort extract and Art v 1 (PCC 0.87, p<0.01; Fig. 1D) and a moderate agreement (64.1%) between extract and major-allergen results (Table 3).
Ragweed: Two hundred and fifty-two patients with measured IgE against extract of ragweed and Amb a 1 as the major allergen were included. Median age was 32.0 years (6.1-74.3yrs). Of these patients 217 were positive for the extract and 161 for the major allergen Amb a 1. While 71.3% of extract positive patients were also positive to the major allergen, 11.9% of all patients were negative for both. Five patients had a negative result for the extract while testing positive for Amb a 1 (1 of these patients were prescribed AIT for ragweed). On the other hand, 61 had a positive extract and a negative Amb a 1 result. Of these patients only 1 was prescribed AIT for ragweed, 5 were advised against AIT and 6 were prescribed AIT for mugwort (as they were positive for Art v 1).
There was a moderate correlation between ragweed extract and Amb a 1 (PCC 0.71, p < 0.01; Fig. 1E) and moderate agreement (73.8%) between extract and major-allergen results (Table 3).