Specific IgE response to different grass pollen allergen components in children undergoing sublingual immunotherapy

We investigated in 30 children (19 males and 11 females, mean age 11.3 years), 19 treated with sublingual immunotherapy (SLIT) by a 5-grass extract and 11 untreated, the sIgE and sIgG4 response to the different allergen components.Significant increases (p？<？0.001) were detected for Phl p 1, Phl p 2, Phl p 5, and Phl p 6, while sIgE levels induced in response to Phl p 7 and Phl p 12 were low or absent at baseline and unchanged following SLIT treatment; no new sensitisation was detected. As to IgG4, significant increases were found for Phl p2 and Phl p 5, while the increase for Phl p 12 was not significant. In the control group, no significant increase in sIgE for any single allergen component was found.These findings confirm that the initial phase of SLIT with a grass pollen extract enhances the sIgE synthesis and show that the sIgE response concerns the same allergen components which induce IgE reactivity during natural exposure.Grass pollen is a major cause of respiratory allergy worldwide [1,2]. Grasses are botanically classified in the family of Gramineae and in particular in the subfamily of Pooideae, which includes the species most commonly responsible of allergic sensitisation, such as Anthoxantum odoratum, Dactylis glomerata, Festuca elatior, Holcus lanatus, Lolium perenne, Phleum pratense, and Poa pratensis. Another species causing respiratory allergy is Cynodon dactylon, which belongs to the subfamily of Panicoideae. These species have variable importance in different geographical areas. In Europe, Dactylis glomerata, Poa pratensis, Lolium perenne and Anthoxantum odoratum are homogeneously distributed, while Phleum pratense is the dominant grass in Northern regions and in the United Kingdom, and Cynodon dactylon is present only in Southern regions [1]. To date, more than 150 allergens from 52 grass species are known, classified in 13 groups according to similar physicochemical and immunologic properties [3,4]. Among these allergens, the molecules from Phleu