Background: Atopy is a multifactorial disease, the pathogenesis of which is influenced by both genetic and environmental conditions. Genes in the HLA region have been involved in the control of the IgE response.
Objective: In order to investigate whether allergy to house dust mite is associated with HLA in our population, we performed sib-pair analysis in 18 families and a case/control study of 161 non-related individuals.
Methods: Levels of total and specific IgE were determined, skin-prick tests were carried out and clinical history was reviewed for every subject in the study. HLA class II typing was performed by the polymerase chain reaction with sequence specific primers.
Results: We observed a significant difference from expected values in haplotypes shared by affected sibs; however, the case/control study did not reveal any association with any particular allele.
Conclusion: These results suggest that any particular HLA-DRB1/DQA1/DQB1 allele is responsible for the development of allergy to house dust mite in the Spanish population. Some other locus in or close to the HLA region might be involved, e.g., the tumour necrosis factor gene, a possibility that would explain the significant difference from expected values in the segregation of HLA haplotypes.