Alimentary Pharmacology and Therapeutics Letters to the Editors
Letter: the rs12979860 and ss469415590 polymorphisms of IFNL4 gene are in strong linkage disequilibrium in Caucasian patients with chronic hepatitis C – authors’ reply A. F. St€attermayer & P. Ferenci Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria. E-mail: [email protected]
SIRS; We thank Drs Keshvari and Alavian and their collaborators for their comment on our recently published paper on the effect of the polymorphisms of IFNL4 and IL28B on treatment response to interferon/ribavirin therapy in patients with chronic hepatitis C.1, 2 Keshvari et al. conﬁrmed our data in Iranian patients with chronic hepatitis C showing a strong linkage disequilibrium between the polymorphisms in rs12979860 (upstream of IL28B) and ss469415590 (IFNL4). We agree that, according to this strong correlation, both variants are equally informative in predicting treatment-induced viral clearance. As rs12979860 is located three kilobases upstream of IL28B and within intron 1 of IFNL4,3 we also agree that SNP rs12979860 should be further referred to as IFNL4 instead of IL28B, but this can only be done on an international level. Whether to base treat-
Letter: switches of 5-aminosalicylates in ulcerative colitis, risk of relapse and ascertainment bias H. Curtis*, S. Jones† & P. Treasure‡ *Princess Royal Hospital, Farnborough, UK. † Synapse Medical Resourcing Ltd, London, UK. ‡ Peter Treasure Statistical Services Ltd, King’s Lynn, UK. E-mail: [email protected]
SIRS, The switching increased for those 344
recent article by Robinson et al. suggests that adherent patients on Asacol leads to an rate of ﬂare. The ﬂare rates quoted are 26.3% switched (the comparison group) vs. 7.5% for
ment decisions in Caucasian patients on rs12979860 or ss469415590 polymorphism is up to the judgment of the physician, as both polymorphisms are strong and reliable predictors of treatment response to interferon-based therapies. However, we would like to reinforce that the IL28B SNP rs8099917, commonly used in Eastern Asian populations, only moderately correlated with ss469415590 (see ﬁgure 1 of our paper).2 This difference is not surprising as SNP rs8099917 resides nine kilobases upstream of IL28B and hence upstream of IFNL4. Therefore, it is less useful for guiding treatment decisions in Caucasian patients.
ACKNOWLEDGEMENT The authors’ declarations of personal and ﬁnancial interests are unchanged from those in the original article.2 REFERENCES 1. Keshvari M, Pouryasin A, Behnava B, Sharaﬁ H, Hajarizadeh B, Alavian SM. Letter: the rs12979860 and ss469415590 polymorphisms of IFNL4 gene are in strong linkage disequilibrium in Caucasian patients with chronic hepatitis C. Aliment Pharmacol Ther 2014; 39: 343. 2. St€attermayer AF, Strassl R, Maieron A, et al. Polymorphisms of interferon-k4 and IL28B – effects on treatment response to interferon/ribavirin in patients with chronic hepatitis C. Aliment Pharmacol Ther 2013; 39: 104–11. 3. Prokunina-Olsson L, Muchmore B, Tang W, et al. A variant upstream of IFNL3 (IL28B) creating a new interferon gene IFNL4 is associated with impaired clearance of hepatitis C virus. Nature Gen 2013; 45: 164–71.
those not switched (the reference group) over an 18-month period.1 A 2012 Cochrane Collaboration meta-analysis of clinical trial data for UC maintenance therapy2 reported that on average, 41% of patients on 5-aminosalicylate (5-ASA) maintenance therapy ﬂared over a 12-month period. D’Haens and Sandborn looked at endoscopic remission in 826 patients on 5-ASA maintenance therapy,3 and reported loss of endoscopic remission rates of 23% at 6 months, on Asacol maintenance therapy. Given what is known about UC ﬂare rates in patients on 5-ASA maintenance therapy, the ﬂare rate for the reference group in this paper (which equates to