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Galindo-Feria AS, Horuluoglu B, Day J, Fernandes-Cerqueira C, Wigren E, Gräslund S, Proudman S, Lundberg IE, Limaye V. Autoantibodies against Four-and-a-Half-LIM Domain 1 (FHL1) in Inflammatory Myopathies: Results from an Australian Single-Center Cohort. Rheumatology (Oxford) 2022; 61:4145-4154. [PMID: 35022656 PMCID: PMC9536793 DOI: 10.1093/rheumatology/keac003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Objectives To determine the prevalence and associations of autoantibodies targeting a muscle-specific autoantigen, four-and-a-half-LIM-domain 1 (FHL1), in South Australian patients with histologically-confirmed idiopathic inflammatory myopathies (IIM) and in patients with SSc. Material and methods Sera from patients with IIM (n = 267) from the South Australian Myositis Database (SAMD), SSc (n = 174) from the Australian Scleroderma Cohort Study (ASCS) and healthy controls (HC, n = 100) were analysed for anti-FHL1 autoantibodies by Enzyme-Linked ImmunoSorbent Assay (ELISA). Results Autoantibodies to FHL1 were more frequent in patients with IIM (37/267, 13.8%) compared with SSc (12/174, 7%) (P < 0.02) and HC (2/100, 2%) (P < 0.001). The most common IIM subtypes among FHL1+ IIM patients were (32%) and IBM (2/37, 32%). No statistically significant differences in muscular or extra-muscular manifestations of IIM were found when comparing patients who were anti-FHL1+ with their anti-FHL1– counterparts. In 29/37 (78%) anti-FHL1+ patients, no myositis-specific autoantibodies (MSA) were present. In FHL1+ muscle biopsies, there was less frequent infiltration by CD45+ cells (P = 0.04). There was a trend for HLA alleles DRB1*07 and DRB1*15 to be more frequent in anti-FHL1+ compared with anti-FHL1– patients (9/25 vs 19/113, P = 0.09 and 8/25 vs 15/114, P = 0.09, respectively). Conclusions We report a substantial prevalence (13.8%) of anti-FHL1 autoantibodies in a large cohort of patients with histologically confirmed IIM; 75% of these cases did not have a detectable myositis-specific autoantibody. Anti-FHL1 autoantibodies were also detected in a subgroup of patients with SSc (7%), indicating that anti-FHL1 autoantibodies may not be myositis-specific. The trend towards an HLA-DR association might indicate a specific immune response to the FHL1 protein.
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Affiliation(s)
- Angeles S Galindo-Feria
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska University Hospital Solna, Stockholm, Sweden, Karolinska Institutet
| | - Begum Horuluoglu
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska University Hospital Solna, Stockholm, Sweden, Karolinska Institutet
| | - Jessica Day
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia.,School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia
| | - Catia Fernandes-Cerqueira
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska University Hospital Solna, Stockholm, Sweden, Karolinska Institutet.,4Dcell, Montreuil, France
| | - Edvard Wigren
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Structural Genomics Consortium, Rheumatology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Susanne Gräslund
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Structural Genomics Consortium, Rheumatology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Susanna Proudman
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia.,Discipline of Medicine, University of Adelaide, Adelaide, Australia
| | - Ingrid E Lundberg
- Division of Rheumatology, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden.,Center for Molecular Medicine, Karolinska University Hospital Solna, Stockholm, Sweden, Karolinska Institutet
| | - Vidya Limaye
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, Australia.,Discipline of Medicine, University of Adelaide, Adelaide, Australia
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