Clarke Alex, Perry Elizabeth, Kelly Clive, De Soyza Anthony, Heesom Kate, Gold Leslie I, Ollier William, Hutchinson David, Eggleton P
Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.
Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK; Rheumatology Department,Musgrove Park Hospital, Taunton, Somerset, UK.
Int J Biochem Cell Biol. 2017 Aug;89:199-206. doi: 10.1016/j.biocel.2017.06.013. Epub 2017 Jun 24.
Calreticulin (CRT) and citrullinated (citCRT) are implicated in rheumatoid arthritis (RA) pathology. citCRT binds to RA shared epitopes (SE) on HLA-DR molecules with high affinity and triggers pro-inflammatory events in adjacent cells. The aim of the study was to detect the presence of citCRT prior to developing RA and evaluate if citCT is a target for autoantibodies in RA cohorts with and without lung disease. Antibodies were assessed by ELISA against native CRT, citCRT and general protein citrullination, in sera from 50 RA patients without lung disease, 122 bronchiectasis (BR) patients, 52 bronchiectasis patients with RA (BRRA), 87 asthma patients and 77 healthy controls (HC). Serum citCRT was detected by immunoblotting and mass spectrometry. Genomic DNA was genotyped for HLA-DRB1 alleles. Patients were assessed for DAS28, rheumatoid factor, and anti-cyclic citrullinated peptide antibodies. Extracellular citCRT was detected in BR patients sera prior to them developing RA. A citCRT SE binding peptide GEWKPRQIDNPDYK was identified. Anti-CRT antibodies were observed in 18% of BR patients with or without RA. Anti-citCRT antibodies were observed in ∼35% of BR or RA patients, increasing to 58% in BRRA patients. In the RA alone patients 7/20 (35%) who were negative for RF and anti-CCP were anti-CRT antibody positive and had higher DAS28 scores than triple negative RA alone patients. Three of the four BR patients who developed RA over 18 months were anti-citCRT+ve SE. The detection of citCRT in BR and development of anti-citCRT in BR patients suggests citCRT antigens are early targets of antigenicity in these patients, especially in SE patients prior to the onset of RA.
钙网蛋白（CRT）和瓜氨酸化的钙网蛋白（citCRT）与类风湿性关节炎（RA）的病理过程有关。citCRT以高亲和力与HLA - DR分子上的RA共享表位（SE）结合，并在相邻细胞中引发促炎事件。本研究的目的是在RA发病前检测citCRT的存在，并评估citCT是否是有或无肺部疾病的RA队列中自身抗体的靶标。通过酶联免疫吸附测定（ELISA）针对天然CRT、citCRT和一般蛋白质瓜氨酸化，检测了50例无肺部疾病的RA患者、122例支气管扩张（BR）患者、52例合并RA的支气管扩张患者（BRRA）、87例哮喘患者和77例健康对照（HC）血清中的抗体。通过免疫印迹和质谱法检测血清citCRT。对HLA - DRB1等位基因进行基因组DNA基因分型。评估患者的疾病活动评分28（DAS28）、类风湿因子和抗环瓜氨酸肽抗体。在BR患者发展为RA之前，在其血清中检测到细胞外citCRT。鉴定出一种citCRT SE结合肽GEWKPRQIDNPDYK。在18%的有或无RA的BR患者中观察到抗CRT抗体。在约35%的BR或RA患者中观察到抗citCRT抗体，在BRRA患者中增至58%。在仅患RA的患者中，20例类风湿因子（RF）和抗环瓜氨酸肽（anti - CCP）阴性的患者中有7例（35%）抗CRT抗体呈阳性，且其DAS28评分高于仅患RA的三联阴性患者。在18个月内发展为RA的4例BR患者中有3例抗citCRT + ve SE。在BR中检测到citCRT以及在BR患者中出现抗citCRT表明，citCRT抗原是这些患者，尤其是RA发病前的SE患者中抗原性的早期靶标。
