Objectives/hypothesis: Genetic etiology is suspected in the development of nasal polyposis on the basis of familial aggregation. This study investigated whether there is an association between HLA-DRB1, -DQA1, and -DQB1 alleles and developing nasal polyposis.
Study design: Data from 50 polypectomized patients were compared with data from 50 healthy randomly selected controls. Polyp score, possible asthma, aspirin sensitivity, and ASA triad were also recorded.
Methods: Genotyping of HLA-DRB1 alleles was carried out with the Dynal RELI SSO HLA-DRB, a direct DNA probe test that utilizes a polymerase chain reaction (PCR) and nucleic acid hybridization for the differentiation of 70 HLA-DRB alleles and 9 supertypes. For DQA1* genotyping PCR-RFLP (restriction fragment length polymorphism) was used, differentiating eight alleles. The DQB1* typing was carried out using a INNO-LiPA DQB PCR-reverse hybridization kit, allowing the discrimination of 30 alleles.
Results: People carrying the HLA-DR7-DQA1*0201, and -DQB1*0202 haplotype were found to have a two to three times higher odds ratios (ORs) for developing the disease, compared with controls. Patients with ASA triad carried the above-mentioned DR7 allele with the linked alleles significantly more often (P < .001). Subjects carrying HLA-DR5 allele and the linked alleles had lower odds ratio values.
Conclusion: These results underline that allergy is not conditional for the formation of nasal polyps as thought before. Nasal polyposis associated with asthma and aspirin sensitivity is probably a unique form of nasal polyps. The authors plan further investigations in this field.