HLA-DRB1, -DQA1, and -DQB1 genotypes in patients with nasal polyposis

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.

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.

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.

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.

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.