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No evidence for a critical role of the unfolded protein response in synovium and blood of patients with ankylosing spondylitis
  1. Barbara Neerinckx1,2,
  2. Shea Carter1,
  3. Rik J Lories1,2
  1. 1 Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium
  2. 2 Division of Rheumatology, UZ Leuven, Leuven, Belgium
  1. Correspondence to Dr R Lories, Division of Rheumatology, UZ Leuven, Herestraat 49, Leuven 3000, Belgium; Rik.Lories{at}

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HLA-B27 is the strongest genetic risk factor for ankylosing spondylitis (AS), but how it contributes to AS remains unknown. Increased endoplasmic reticulum stress, triggered by misfolding of HLA-B27 heavy chains, and activation of the unfolded protein response (UPR) have been proposed as underlying mechanisms.1 Studies in the HLA-B27/β2 microglobulin transgenic rat show a temporal and quantitative relationship between HLA-B27 upregulation and activation of the UPR in macrophages of diseased rats.2 ,3 In AS patients, some small studies show conflicting results.47 We aimed to determine if the HLA-B27-related UPR, present in transgenic rats, is relevant in blood and synovial tissues of AS patients. We compared ex vivo UPR gene expression in synovium and blood from AS patients with expression in the same tissues and cells of healthy controls and patients with other rheumatic diseases.

We obtained synovial tissues from inflamed knees from patients with AS, other forms of spondyloarthritis …

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  • Funding This project was supported by FWO grant G.0829.11 and the investigator initiated LEGEAS (Leuven Gent Ankylosing Spondylitis) grant supported by Pfizer.

  • Competing interests BN is the recipient of an Aspirant PhD fellowship from the Flanders Research Foundation (FWO Vlaanderen).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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