Calreticulin (CRT) was identified as a frequent target of serum autoantibodies (Ab) in various diseases, but anti-CRT Ab of IgA isotype were described only in coeliac (CLD) and some hepatic diseases. Employing ELISA with recombinant CRT we found significantly higher (P<0.001) levels of IgA anti-CRT Ab in sera of patients with primary biliary cirrhosis (PBC) (77.6+/-8.9 AU/mean+/-SE), autoimmune hepatitis (AIH) (105.1+/-9.2 AU) and alcoholic liver cirrhosis (ALC) (193.5+/-21.0 AU) relative to healthy controls (38.6+/-2.0 AU). The levels of IgG anti-CRT Ab in sera of patients with PBC (59.5+/-3.4 AU), AIH (89.7+/-7.9 AU) and ALC (86.4+/-6.2 AU) were also significantly increased (P<0.001) when compared with controls (38.5+/-2.1 AU). Pepscan technique with decapeptides of CRT (each overlapping by eight amino acids) revealed antigenic epitopes of this molecule recognised by IgA Ab of almost all tested patients-KGKNVLINKD and QVKSGTIFDNFL. We also identified disease specific antigenic epitopes on CRT molecule, predominantly recognised by IgA Ab of patients suffering from a particular disease: GGYVKLFPNS and YVKLFPNSLD in AIH (83%, 92% of patients), GLQTSQDARF and EQRLKEEEED in CLD (both 75%) and ASKPEDWDER in ALC (67%). Identification of disease specific CRT epitopes contributes to clarification of autoreactivity against this molecule.

中文翻译：

---

肝和腹腔疾病患者的IgA自身抗体识别的钙网蛋白表位。

钙网蛋白（CRT）被确定为多种疾病中血清自身抗体（Ab）的常见靶标，但仅在腹腔（CLD）和某些肝脏疾病中描述了IgA同种型的抗CRT Ab。使用重组CRT的ELISA我们发现原发性胆汁性肝硬化（PBC）（77.6 +/- 8.9 AU /平均值+/- SE），自身免疫性肝炎（AIH）患者的血清中IgA抗CRT Ab的水平显着更高（P <0.001） ）（105.1 +/- 9.2 AU）和酒精性肝硬化（ALC）（193.5 +/- 21.0 AU）相对于健康对照组（38.6 +/- 2.0 AU）。PBC（59.5 +/- 3.4 AU），AIH（89.7 +/- 7.9 AU）和ALC（86.4 +/- 6.2 AU）患者血清中的IgG抗CRT Ab水平也显着升高（P <0.001 ）与对照（38.5 +/- 2.1 AU）相比。带有CRT十肽的Pepscan技术（每个肽都重叠八个氨基酸）揭示了该分子的抗原表位，几乎所有受测患者KGKNVLINKD和QVKSGTIFDNFL被IgA Ab识别。我们还确定了CRT分子上特定于疾病的抗原表位，主要由患有特定疾病的患者的IgA Ab识别：AIH中的GGYVKLFPNS和YVKLFPNSLD（83％，患者的92％），CLD中的GLQTSQDARF和EQRLKEEEED（均为75％）和ALC中的ASKPEDWDER（67％）。疾病特异性CRT表位的鉴定有助于阐明对该分子的自身反应性。IgA Ab主要识别患有特定疾病的患者：AIH中的GGYVKLFPNS和YVKLFPNSLD（83％，占92％），CLD中的GLQTSQDARF和EQRLKEEEED（均为75％）和ALC中的ASKPEDWDER（占67％）。疾病特异性CRT表位的鉴定有助于阐明对该分子的自身反应性。IgA Ab主要识别患有特定疾病的患者：AIH中的GGYVKLFPNS和YVKLFPNSLD（83％，占92％），CLD中的GLQTSQDARF和EQRLKEEEED（均为75％）和ALC中的ASKPEDWDER（占67％）。疾病特异性CRT表位的鉴定有助于阐明对该分子的自身反应性。