IL23R genotyping

DNA was isolated using the Puregene blood core kit A (Qiagen) from peripheral blood mononuclear cells in stored whole blood samples (−20°C). Samples were quantified using a Nanodrop ND-1000 Spectrophotometer (Nanodrop Technologies, Wilmington, DE, USA). Genotyping was performed using commercial Taqman (Applied Biosystems, Foster City, CA, USA)-based RT-PCR allelic discrimination assays for three non-synonymous single-nucleotide polymorphisms (SNPs) in the IL23R gene region [rs11209026 (A is rare but protective allele, OR = 0.69), rs10489629 (A is protective allele, OR = 0.83) and rs11209032 (A is risk allele, OR = 1.3] [2, 11].