Background: Allergic asthma is a multifactorial and probably multigenic inflammatory disease of the upper airways, and has been associated with the HLA class II alleles DR4 and DR7. Here we investigated possible associations with other polymorphic susceptibility/resistance genes located within the major histocompatibility complex, i.e., the genes coding the major 70-kDa heat-shock proteins (HSP; Hsp70) hsp70-1, hsp70-2, and hsp70-HOM, whose products are overexpressed in the bronchi of asthmatic patients.
Methods: Genomic DNA was extracted from peripheral blood lymphocytes or buccal epithelial cells of 48 patients with allergic asthma and 31 selected nonatopic control subjects, in whom we previously reported a strong association of atopy with DR4/DR7 alleles.
Results: No evidence was found for an independent role of hsp70 gene polymorphism in susceptibility to allergic asthma. However, hsp70 alleles might be involved in extended haplotypes of HLA markers.
Conclusions: Our data suggest that Hsp70 overexpression in asthma results from complex interactions between environmental exposures and genetic background rather than from specific genetic variations in hsp70 genes.