J C Nossent1,2, S Johnsen3, G Bakland2,4. 1. a University of Western Australia, Sir Charles Gairdner Hospital , Perth , Australia. 2. b Department of Clinical Medicine , The Arctic University , Tromsø , Norway. 3. c Norwegian University of Life Sciences , Aars , Norway. 4. d University Hospital of North Norway (UNN) , Tromsø , Norway.
Abstract
OBJECTIVES: Endoplasmic reticulum aminopeptidase 1 (ERAP1) gene variants diminish the risk of developing ankylosing spondylitis (AS) through a reduction in ERAP1 activity. We investigated whether disease expression was altered in patients who developed AS despite the presence of two protective ERAP1 variants. METHOD: We conducted a cross-sectional and longitudinal cohort study of patients with established AS (n = 334, 90% B27+, mean age at study 45 years) for whom clinical data and biological samples were collected during a research visit. Genotyping for the single nucleotide polymorphisms (SNPs) rs27044 and rs30187 was performed on genomic DNA by reverse transcription polymerase chain reaction (RT-PCR) with interleukin (IL)-6 and tumour necrosis factor (TNF) levels determined by a sandwich enzyme-linked immunosorbent assay (ELISA). Associations between genotypes and haplotypes, clinical and serological findings were analysed using SNPstats. RESULTS: Both SNPs were in strong linkage disequilibrium and formed three common haplotypes (C/C 0.65, G/T 0.30, and C/T 0.04). Haplotype C/T carried a lower risk for uveitis [odds ratio (OR) 0.32, p = 0.03] and elevated C-reactive protein (CRP) levels (OR 0.26, p = 0.04). There was no effect of ERAP1 haplotypes on cytokine levels or major outcomes after 8 years of follow-up. CONCLUSIONS: The ERAP1 rs27044/rs30187 haplotype C/T is associated with lower risk of extraspinal disease and systemic inflammation in Nordic AS patients but has no impact on IL-6 or TNF levels.
OBJECTIVES:Endoplasmic reticulum aminopeptidase 1 (ERAP1) gene variants diminish the risk of developing ankylosing spondylitis (AS) through a reduction in ERAP1 activity. We investigated whether disease expression was altered in patients who developed AS despite the presence of two protective ERAP1 variants. METHOD: We conducted a cross-sectional and longitudinal cohort study of patients with established AS (n = 334, 90% B27+, mean age at study 45 years) for whom clinical data and biological samples were collected during a research visit. Genotyping for the single nucleotide polymorphisms (SNPs) rs27044 and rs30187 was performed on genomic DNA by reverse transcription polymerase chain reaction (RT-PCR) with interleukin (IL)-6 and tumour necrosis factor (TNF) levels determined by a sandwich enzyme-linked immunosorbent assay (ELISA). Associations between genotypes and haplotypes, clinical and serological findings were analysed using SNPstats. RESULTS: Both SNPs were in strong linkage disequilibrium and formed three common haplotypes (C/C 0.65, G/T 0.30, and C/T 0.04). Haplotype C/T carried a lower risk for uveitis [odds ratio (OR) 0.32, p = 0.03] and elevated C-reactive protein (CRP) levels (OR 0.26, p = 0.04). There was no effect of ERAP1 haplotypes on cytokine levels or major outcomes after 8 years of follow-up. CONCLUSIONS: The ERAP1rs27044/rs30187 haplotype C/T is associated with lower risk of extraspinal disease and systemic inflammation in Nordic AS patients but has no impact on IL-6 or TNF levels.
Authors: Jonas J W Kuiper; Jessica van Setten; Matthew Devall; Mircea Cretu-Stancu; Sanne Hiddingh; Roel A Ophoff; Tom O A R Missotten; Mirjam van Velthoven; Anneke I Den Hollander; Carel B Hoyng; Edward James; Emma Reeves; Miguel Cordero-Coma; Alejandro Fonollosa; Alfredo Adán; Javier Martín; Bobby P C Koeleman; Joke H de Boer; Sara L Pulit; Ana Márquez; Timothy R D J Radstake Journal: Hum Mol Genet Date: 2018-12-15 Impact factor: 6.150