Prevalence and Clinical Relevance of IgE Sensitization to Profilin in Childhood: A Multicenter Study.

BACKGROUND: Little is known about the prevalence and clinical relevance of hypersensitivity to the plant panallergen profilin in children. OBJECTIVES: The present study aimed to investigate prevalence, risk factors and clinical relevance of profilin sensitization in a large cohort of Italian children of different ages living in different geographic areas. METHODS: Children with pollen allergy enrolled by 16 pediatric outpatient clinics sited in three main geographic areas of Italy were studied. SPT were carried out with commercial pollen extracts and a commercial purified date palm pollen profilin. IgE specific for allergenic pollen molecules, Phl p 12 (grass profilin) and Pru p 3 (peach lipid transfer protein) were tested by ImmunoCAP FEIA. RESULTS: IgE to Phl p 12 (≥0.35 kU/l) was observed in 296 of the 1,271 participants (23%), including 17 of the 108 (16%) preschool children. Profilin SPT was positive (≥3 mm) in 320/1,271 (25%) participants. The two diagnostic methods were concordant in 1,151 (91%, p < 0.0001) cases. Phl p 12 IgE prevalence declined from northern to southern Italy and was directly associated with IgE to Phl p 1 and/or Phl p 5 and Ole e 1. Among children with IgE to Phl p 12, OAS was provoked by kiwi, melon, watermelon, banana, apricot and cucumber. CONCLUSIONS: Profilin sensitization is very frequent among pollen-allergic children, occurs at a very young age and contributes to the development of childhood OAS with a typical pattern of offending foods. Pediatricians should always consider IgE sensitization to profilin while examining pollen-allergic children, even if they are at preschool age.

The effect of component-resolved diagnosis on specific immunotherapy prescription in children with hay fever.

BACKGROUND: Sensitization to profilins and other cross-reacting molecules might hinder proper specific immunotherapy (SIT) prescription in polysensitized patients with pollen-related allergic rhinitis (AR). In these patients, component-resolved diagnosis (CRD) might modify SIT prescription by improving the identification of the disease-eliciting pollen sources. OBJECTIVES: We sought to measure the effect of CRD on SIT prescription in children with pollen-related AR. METHODS: Children (n = 651) with moderate-to-severe pollen-related AR were recruited between May 2009 and June 2011 in 16 Italian outpatient clinics. Skin prick test (SPT) reactivity to grass, cypress, olive, mugwort, pellitory, and/or Betulaceae pollen was considered clinically relevant if symptoms occurred during the corresponding peak pollen season. IgE sensitization to Phl p 1, Phl p 5, Bet v 1, Cup a 1, Art v 1, Ole e 1, Par j 2, and Phl p 12 (profilin) was measured by using ImmunoCAP. SIT prescription was modeled on SPT responses first and then remodeled considering also CRD according to GA(2)LEN-European Academy of Allergology and Clinical Immunology guidelines and the opinions of 14 pediatric allergists. RESULTS: No IgE to the respective major allergens was detected in significant proportions of patients with supposed clinically relevant sensitization to mugwort (45/65 [69%]), Betulaceae (146/252 [60%]), pellitory (78/257 [30%]), olive (111/390 [28%]), cypress (28/184 [15%]), and grass (56/568 [10%]). IgE to profilins, polcalcins, or both could justify 173 (37%) of 464 of these SPT reactions. After CRD, the SPT-based decision on SIT prescription or composition was changed in 277 (42%) of 651 or 315 (48%) of 651 children according to the European or American approach, respectively, and in 305 (47%) of 651 children according to the opinion of the 14 local pediatric allergists. CONCLUSIONS: In children with pollen-related AR, applying CRD leads to changes in a large proportion of SIT prescriptions as opposed to relying on clinical history and SPT alone. The hypothesis that CRD-guided prescription improves SIT efficacy deserves to be tested.