Clinical significance of myositis-specific autoantibodies

Figures & data

Figure 1. Schematic subcategorization of patients with different myositis-specific autoantibodies (MSAs). Because IIM patients with different MSAs have common clinical characteristics, each MSA-positive patient can be determined to be a subset of IIM. The horizontal axis shows the spectrum of skin disease and muscle involvement, and the vertical axis shows the acute or chronic type of ILD.

Table 1. The frequency and significance of myositis-specific autoantibodies in adult IIM patients.

MSAs	Reported year	Autoantigen	Frequency in IIM	Significance
Anti-ARS		Aminoacyl-tRNA synthetase	20–40%	Anti-synthetase syndrome Myositis, ILD, arthritis Raynaud's phenomenon Fever, mechanic's hand
Anti-Jo-1	1983	Histidyl	15–20%
Anti-PL-7	1984	Threonyl	<5%
Anti-PL-12	1986	Alanyl	<5%
Anti-OJ	1990	Isoleucyl	<5%
Anti-EJ	1990	Glycyl	<5%
Anti-KS	1999	Asparaginyl	<5%
Anti-Ha	2005	Tyrosyl	A case report
Anti-Zo	2007	Phenylalanyl	A case report
Anti-SRP	1986	Signal recognition particle	3–10%	Necrotizing myopathy, Severe myositis, resistant to treatment, recurrent disease course
Anti-Mi-2	1985	Mi-2 (NuRD helicase)	3–8%	Child and adult DM
Anti-MDA5	2005	melanoma Differentiation- associated gene5	8–20%	CADM, rapidly progressive ILD
Anti-TIF1-γ	2006	Transcriptional intermediary factor 1-γ	5–7%	DM, malignancy associated DM
Anti-NXP2	2007	Nuclear matrix protein 2 (MORC3)	5–8%	DM, malignancy, skin calcification in child
Anti-SAE	2007	Small ubiquitin-like Modifier 1 (SUMO-1) activating enzyme	1–4%	DM
Anti-HMGCR	2010	3-Hydroxy-3-Methylglutaryl-CoA Reductase	5–8%	Necrotizing myopathy, statin-induced myopathy

IIM: idiopathic inflammatory myopathy; ILD: interstitial lung disease; DM: dermatomyositis; CADM: clinically amyopathic DM.

Figure 2. The survival rate of patient groups with different myositis-specific autoantibodies (MSAs). Overall, 245 Japanese IIM patients who visited our department were divided into groups, myositis-specific autoantibody-positive subsets (anti-Mi-2, anti-SRP, anti-ARS, anti-TIF1-γ, anti-MDA5 and negative for MSAs), and their survival rate was plotted.