An automated rapid detection system using the quenching probe method for detecting interleukin 28 B and inosine triphosphatase single nucleotide polymorphisms in chronic hepatitis C

Summary Single nucleotide polymorphisms ( SNP s) in the interleukin 28 B gene ( IL28B ) are good pretreatment predictors of anti‐hepatitis C virus ( HCV ) therapy with interferon. SNP s of the inosine triphosphatase ( ITPA ) gene are associated with reduced haemoglobin levels during treatment with ribavirin. The i‐densy™ (Arkray, Inc.), which is based on the quenching probe ( QP ) method, automatically detects target genes in blood samples by fluorescence quenching within 100 min. Using a QP and primer set, a gene amplification response is generated that can quickly and easily detect a specific gene's arrangement by fluorometry. The present study was conducted to compare the utility of i‐densy ( QP method) with that of conventional direct sequencing ( DS ) for detecting SNP s in the IL28B and ITPA genes in chronic hepatitis C patients. Between June 2011 and J anuary 2012, 73 consecutive patients underwent genotyping of IL 28B, and 54 patients underwent genotyping of ITPA . All of the patients were seropositive for HCV ‐ RNA . The IL 28B and ITPA genotypes were tested for bi‐allelic polymorphisms in rs8099917 ( T / T , T / G and G / G ; minor allele, G ) and rs1127354 ( C / C , C / A and A / A ; minor allele, A ), respectively. The results obtained with the QP method were identical to those obtained with the conventional DS method. The frequency of the IL28B genotypes TT , GT and GG were 74%, 24.7% and 1.4%, respectively, and those of the ITPA genotypes CC , AC and AA were 68.5%, 29.6% and 1.9%, respectively. These results indicate that the i‐densy using the QP method can automatically, quickly and easily identify genotypes of IL28B and ITPA .