Myositis-specific and myositis-associated autoantibodies in a large Indian cohort of inflammatory myositis

Latika Gupta, R Naveen, Priyanka Gaur, Vikas Agarwal, Rohit Aggarwal

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: The Idiopathic Inflammatory Myositis (IIM) are heterogenous with distinct clinical phenotypes associated with specific myositis specific antibodies (MSA) and myositis associated antibodies (MAA).

OBJECTIVES: To evaluate the frequency, pattern and associations of MSA/MAA in a large Indian cohort of IIM.

METHODS: Adult and juvenile IIM (2017 ACR/EULAR criteria), were recruited in the MyoCite cohort between 2017and 2020 at a tertiary center in Northern India. Standardized clinical and laboratory variables were extracted from the database archive. Serum samples were evaluated for the presence of MSAs/MAAs by Line immunoassay and anti-nuclear antibodies (ANA) by Immunofluorescence assay (IFA). The prevalence and clinical associations of different MSA/MAAs were assessed.

RESULTS: MSA and MAAs were tested in 250 IIM patients (214 adults, 36 children) of age [40 (30-49), 13 (7.5-16) years] and disease duration [ 7 (3-17), 6 (2-17) months] comprising predominantly of Dermatomyositis (DM) followed by Overlap myositis (OM). MSAs/MAAs were found in 148 (59.2%, 60.7% adults and 50% JIIM), of which two-thirds were MSA (95, 64% overall). Two cases (0.8%) had more than one MSA. In adult IIM, the most common MSA was anti-Jo-1 (10%), whereas it was anti-MDA5 and anti-NXP2 4 (11%) each in Juvenile IIM (JIIM). 76.0% (172/226) were ANA positive, with speckled pattern being the most common (37%,). Nearly two-thirds (54, 61%) of those with negative ANA had MSA/ MAA. Nearly half (18/54, 54.6%) had MSA associated with cytoplasmic patterns. ARS (anti-aminoacyl-tRNA synthetase) were associated with mechanic's hands (OR-7.06), ILD (OR-4.4), and arthritis (OR-2.23). Clinical associations of anti-Jo-1 and non-Jo-1 Anti synthetase syndrome (ASS) did not differ. Anti-MDA-5 associated with oral ulcers (OR-8.3), fever (OR-8.6) and weight loss (OR-7.35) in adults, and arthritis (OR-11.5), and periungual rash (OR-9.6) in children. Anti-TIF-1γ associated with photosensitivity (OR-10.44) and malignancy (OR-34) in adults, and cuticular overgrowth (OR-11.2) in children.

CONCLUSION: Myositis autoantibodies are seen in two-thirds IIMs and are associated with distinct clinical subsets. Jo-1 and non-Jo-1 ASS exhibit similar characteristics. The association of anti-TIF1 γ with malignancy was confirmed in adults. MSA/MAA were present in two-thirds of those with negative ANA and MSA were nearly always mutually exclusive.

Original languageEnglish
Pages (from-to)113-120
Number of pages8
JournalSeminars in arthritis and rheumatism
Volume51
Issue number1
DOIs
Publication statusPublished - Feb 2021

Keywords

  • Adolescent
  • Antibodies, Antinuclear
  • Arthritis
  • Autoantibodies
  • Cohort Studies
  • Humans
  • Myositis/epidemiology

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