Allergy to lipid transfer protein: genetic basis-preliminary results

Lipid transfer proteins (LTP), profilins and PR-10 are the most important panallergens in South-Centre Italy. LTP are stable molecules, predominantly present in the fruit peel, which can induce systemic symptoms after ingestion of plant-derived foods. The aim of our study was to assess the genetic basis related to panallergens sensitization. We wanted to evaluate the possible correlation between HLA-DRB1 haplotypes and food allergy. We enrolled 47 subjects with the history of adverse reactions after the ingestion of plant-derived foods and allergological evaluation (skin prick tests and quantification of specific IgE) positive for some food and at least one panallergen . On the basis of the sensitization to LTP the patients were divided into two groups: LTP+= 36; LTP- = 11. We extracted the genomic DNA from each patient and detected the HLA-DRB1 haplotypes using the INNO-LIPA HLA-DRB1 kit. We compared our results with the literature data about the frequency of HLA-DRB1 haplotypes in South-Centre Italy. We observed a marked prevalence of HLA-DRB1 homozygosity in all examined patients, both positive and negative for LTP (23%), compared to general population (3%). In addition, the HLA-DRB1 13 was twice as frequent in the LTP + group as it was in the general population whereas it was completely absent in the LTP- group. On the other hand, alleles 4, 7 and 15 occurred to be twice more often in LTP- group than in the general population and the LTP + group. This study shows a high rate of sensitization to LTP in the South-Centre Italian population according to the Literature about food allergy in this geographical area, therefore panallergens should be considered a clinically relevant food allergens. Altough further investigations are necessary we hypothesize that the alleles 4, 7, 15 have a protective role against the allergy to LTP. On the other hand the presence of the haplotype HLA-DR1 13 could be a risk factor for LTP allergy.