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Lee AYS, Beroukas D, Brown L, Lucchesi C, Kaur A, Gyedu L, Hughes N, Ng YH, Saran O, Gordon TP, Wang JJ. Identification of a unique anti-Ro60 subset with restricted serological and molecular profiles. Clin Exp Immunol 2020; 203:13-21. [PMID: 32852779 DOI: 10.1111/cei.13508] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/06/2020] [Accepted: 08/14/2020] [Indexed: 12/30/2022] Open
Abstract
Anti-Ro60 is one of the most common and clinically important serum autoantibodies that has a number of diagnostic and predictive capabilities. Most diagnostic laboratories report this simply as a qualitative positive/negative result. The objective of this study was to examine the clinical and serological relevance of a novel subset of anti-Ro60 in patients who display low levels of anti-Ro60 (anti-Ro60low ). We retrospectively identified anti-Ro60 sera during a 12-month period at a major immunopathology diagnostic laboratory in Australia. These all were anti-Ro60-precipitin-positive on the diagnostic gold standard counter-immuno-electrophoresis (CIEP). Lineblot immunoassay was used to stratify patients into either anti-Ro60low or anti-Ro60high subsets. We compared the medical and laboratory parameters associated with each group. Enzyme-linked immunosorbent assay (ELISA) and mass spectrometry techniques were used to analyse the serological and molecular basis behind the two subsets. Anti-Ro60low patients displayed less serological activity than anti-Ro60high patients with less intermolecular spreading, hypergammaglobulinaemia and less tendency to undergo anti-Ro60 isotype-switching than anti-Ro60high patients. Mass spectrometric typing of the anti-Ro60low subset showed restricted variable heavy chain subfamily usage and amino acid point mutations. This subset also displayed clinical relevance, being present in a number of patients with systemic autoimmune rheumatic diseases (SARD). We identify a novel anti-Ro60low patient subset that is distinct from anti-Ro60high patients serologically and molecularly. It is not clear whether they arise from common or separate origins; however, they probably have different developmental pathways to account for the stark difference in immunological maturity. We hence demonstrate significance to anti-Ro60low and justify accurate detection in the diagnostic laboratory.
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Affiliation(s)
- A Y S Lee
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - D Beroukas
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - L Brown
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - C Lucchesi
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - A Kaur
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - L Gyedu
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - N Hughes
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - Y H Ng
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - O Saran
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia
| | - T P Gordon
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
| | - J J Wang
- Department of Immunology, SA Pathology and Flinders Medical Centre, Bedford Park, SA, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia
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