IgG4 levels in relation to Olea europaea immunotherapy

We determined olive pollen-specific IgG4 levels in 100 patients, 39 of whom had been subjected to no immunotherapy (IT) for Olea (31 allergic and 8 nonallergic individuals) and 61 of whom had been administered IT as extracts, including Olea pollen (29 extracts in BUs, 24 allergenic extracts polymerized with glutaraldehyde:Allergoid and 8 extracts standardized in PNUs). IgG4 levels were correlated to the clinical picture, type of extract and average cumulative dose (ACD). We found average IgG4 levels of 0.80 +/- 0.74, 8.60 +/- 13.07 (p < 0.01) and 1.42 +/- 2.5 micrograms/ml (n.s.) for the untreated group and those treated with BU and Allergoid, respectively. The difference between the IT-BU-treated and IT-Allergoid-treated patients was significant at p < 0.01. On the other hand, we found no significant differences among the average IgG4 levels of the three groups in relation to age or sex. The group of asthmatic patients treated with BU extracts had average IgG4 levels of 16 +/- 17.34 micrograms/ml, while those of the rhinoconjunctivitic, non-asthmatic group were 5.05 +/- 6.149 micrograms/ml, with p < 0.05 (Student's "t" test). Thus, patients treated with extracts polymerized with glutaraldehyde had IgG4 levels that were similar to those of the patients subjected to no IT. Also, the group treated with IT extracts standardized in BUs had increased IgG4 levels that were correlated with the cumulative dose, particularly in asthmatic patients.