Interleukin-6 -174 G/C promoter polymorphism and nasal polyposis.

INTRODUCTION

Nasal polyposis is a chronic disease with unknown etiopathogenesis, although inflammatory mechanisms seem to play a role. One of several inflammatory mediators linked to nasal polyposis is Interleukin-6, which has a single nucleotide polymorphism -174 G/C that seems to promote an inflammatory reaction.

OBJECTIVE

To compare the prevalence of the -174 G/C single nucleotide polymorphism between a group of patients with nasal polyposis and a control group.

METHOD: Cross-sectional study with two groups (thirty two patients with nasal polyposis and fifty five controls) to investigate the -174 G/C polymorphism in blood samples. Asthma, aspirin intolerance and atopy were main exclusion criteria. IL-6 genotyping was performed using the PCR method with forward primer 5'-ATGCCAAGTGCTGAGTCACTA-3' and reverse primer 5'-GGAAAATCCCACATTTGATA-3', amplifying a 226-bp DNA fragment that contained the - 174 position. The amplified fragment can be cleaved by restriction enzyme NlaIII when the -174 position presented the C allele in two fragments of 117 and 109-bp, visualized by electrophoresis, classifying participants in GG, GC and CC.

RESULTS

In the nasal polyposis group, 65.62% of the patients had the GG genotype, while in the control group, 41.82% had two G alleles, a statistically significant difference, with an odds ratio of 2.65.

CONCLUSION

The -174 GG genotype was found more frequently in nasal polyposis patients than in controls, when asthma, aspirin intolerance and atopy were excluded.