Background: Aspirin-induced asthma (AIA) affects one in 10 individuals with adult-onset asthma. It is not known if aspirin sensitivity is due to immune mechanisms or to interference with biochemical pathways.
Objective: The study aimed to test for possible involvement of the genes of the Major Histocompatibility Complex (MHC) in AIA.
Methods: HLA-DPB1 and HLA-DRB1 genotyping was carried out by DNA methods in 59 patients with positive challenge tests for AIA and in 48 normal and 57 asthmatic controls.
Results: The DPB1*0301 frequency was increased in AIA patients when compared with normal controls (19.5% vs 5.2%, Odds Ratio = 4.4, 95% Confidence Interval (CI) 1.6-12.1, P = 0.002), and compared with asthmatic controls (4.4%, OR = 5.3, 95% CI = 1.9-14.4, P = 0.0001). The frequency of DPB1*0401 in AIA subjects was decreased when compared with normal controls (28.8% vs 49.0%, OR = 0.42, 95% CI = 0.24-0.74, P = 0.003) and asthmatic controls (45.6%, OR = 0.48, 95% CI = 0.28-0.83, P = 0.008). The results remained significant when corrected for multiple comparisons. There were no significant HLA-DRB1 associations with AIA.
Conclusion: The presence of an HLA association suggests that immune recognition of an unknown antigen may be part of the aetiology of AIA.