Inflammatory myopathy with anti-signal recognition particle antibodies: Case series of 100 patients

Shigeaki Suzuki, Atsuko Nishikawa, Masataka Kuwana, Hiroaki Nishimura, Yurika Watanabe, Jin Nakahara, Yukiko K. Hayashi, Norihiro Suzuki, Ichizo Nishino

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Abstract

Background: Anti-signal recognition particle (SRP) antibodies are used as serological markers of necrotizing myopathy, which is characterized by many necrotic and regenerative muscle fibers without or with minimal inflammatory cell infiltration. The clinical spectrum associated with anti-SRP antibodies seems to be broad. Objective: To describe the clinical characteristics, autoantibodies status, and neurological outcome associated with anti-SRP antibody. Methods: We studied clinical and laboratory findings of 100 patients with inflammatory myopathy and anti-SRP antibodies. Anti-SRP antibodies in serum were detected by the presence of 7S RNA using RNA immunoprecipitation. In addition, enzyme-linked immunosorbent assays (ELISAs) using a 54-kD protein of SRP (SRP54) and 3-hydroxyl-3-methylglutatyl-coenzyme A reductase (HMGCR) were also conducted. Results: The mean onset age of the 61 female and 39 male patients was 51 years (range 4-82 years); duration ≥ 12 months before diagnosis was seen in 23 cases. All patients presented limbs weakness; 63 had severe weakness, 70 neck weakness, 41 dysphagia, and 66 muscle atrophy. Extramuscular symptoms and associated disorders were infrequent. Creatine kinase levels were mostly more than 1000 IU/L. Histological diagnosis showed 84 patients had necrotizing myopathy, and apparent cell infiltration was observed in 16 patients. Anti-SRP54 antibodies were undetectable in 18 serum samples with autoantibodies to 7S RNA. Anti-HMGCR antibodies were positive in 3 patients without the statin treatment, however, were negative in 5 patients with statin-exposure at disease onset. All but 3 patients were treated by corticosteroids and 62 (77 %) of these 81 patients required additional immunotherapy. After 2-years treatment, 22 (27 %) of these 81 patients had poor neurological outcomes with modified Rankin scale scores of 3-5. Multivariate analysis revealed that pediatric disease onset was associated with the poor outcomes. Conclusion: Anti-SRP antibodies are associated with different clinical courses and histological presentations.

Original languageEnglish
Article number61
JournalOrphanet Journal of Rare Diseases
Volume10
Issue number1
DOIs
Publication statusPublished - 2015 May 13

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Signal Recognition Particle
Myositis
Antibodies
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Muscular Diseases
Coenzyme A
Hydroxyl Radical
Autoantibodies
Oxidoreductases
Muscular Atrophy
Creatine Kinase
Deglutition Disorders
Serum
Age of Onset
Immunoprecipitation
Immunotherapy
Anti-Idiotypic Antibodies
Adrenal Cortex Hormones
Neck
Multivariate Analysis

Keywords

  • Autoantibodies
  • ELISA
  • Necrotizing myopathy
  • Outcome
  • RNA immunoprecipitation
  • Signal recognition particle

ASJC Scopus subject areas

  • Medicine(all)
  • Genetics(clinical)
  • Pharmacology (medical)

Cite this

Inflammatory myopathy with anti-signal recognition particle antibodies : Case series of 100 patients. / Suzuki, Shigeaki; Nishikawa, Atsuko; Kuwana, Masataka; Nishimura, Hiroaki; Watanabe, Yurika; Nakahara, Jin; Hayashi, Yukiko K.; Suzuki, Norihiro; Nishino, Ichizo.

In: Orphanet Journal of Rare Diseases, Vol. 10, No. 1, 61, 13.05.2015.

Research output: Contribution to journalArticle

Suzuki, Shigeaki ; Nishikawa, Atsuko ; Kuwana, Masataka ; Nishimura, Hiroaki ; Watanabe, Yurika ; Nakahara, Jin ; Hayashi, Yukiko K. ; Suzuki, Norihiro ; Nishino, Ichizo. / Inflammatory myopathy with anti-signal recognition particle antibodies : Case series of 100 patients. In: Orphanet Journal of Rare Diseases. 2015 ; Vol. 10, No. 1.
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abstract = "Background: Anti-signal recognition particle (SRP) antibodies are used as serological markers of necrotizing myopathy, which is characterized by many necrotic and regenerative muscle fibers without or with minimal inflammatory cell infiltration. The clinical spectrum associated with anti-SRP antibodies seems to be broad. Objective: To describe the clinical characteristics, autoantibodies status, and neurological outcome associated with anti-SRP antibody. Methods: We studied clinical and laboratory findings of 100 patients with inflammatory myopathy and anti-SRP antibodies. Anti-SRP antibodies in serum were detected by the presence of 7S RNA using RNA immunoprecipitation. In addition, enzyme-linked immunosorbent assays (ELISAs) using a 54-kD protein of SRP (SRP54) and 3-hydroxyl-3-methylglutatyl-coenzyme A reductase (HMGCR) were also conducted. Results: The mean onset age of the 61 female and 39 male patients was 51 years (range 4-82 years); duration ≥ 12 months before diagnosis was seen in 23 cases. All patients presented limbs weakness; 63 had severe weakness, 70 neck weakness, 41 dysphagia, and 66 muscle atrophy. Extramuscular symptoms and associated disorders were infrequent. Creatine kinase levels were mostly more than 1000 IU/L. Histological diagnosis showed 84 patients had necrotizing myopathy, and apparent cell infiltration was observed in 16 patients. Anti-SRP54 antibodies were undetectable in 18 serum samples with autoantibodies to 7S RNA. Anti-HMGCR antibodies were positive in 3 patients without the statin treatment, however, were negative in 5 patients with statin-exposure at disease onset. All but 3 patients were treated by corticosteroids and 62 (77 {\%}) of these 81 patients required additional immunotherapy. After 2-years treatment, 22 (27 {\%}) of these 81 patients had poor neurological outcomes with modified Rankin scale scores of 3-5. Multivariate analysis revealed that pediatric disease onset was associated with the poor outcomes. Conclusion: Anti-SRP antibodies are associated with different clinical courses and histological presentations.",
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AU - Suzuki, Shigeaki

AU - Nishikawa, Atsuko

AU - Kuwana, Masataka

AU - Nishimura, Hiroaki

AU - Watanabe, Yurika

AU - Nakahara, Jin

AU - Hayashi, Yukiko K.

AU - Suzuki, Norihiro

AU - Nishino, Ichizo

PY - 2015/5/13

Y1 - 2015/5/13

N2 - Background: Anti-signal recognition particle (SRP) antibodies are used as serological markers of necrotizing myopathy, which is characterized by many necrotic and regenerative muscle fibers without or with minimal inflammatory cell infiltration. The clinical spectrum associated with anti-SRP antibodies seems to be broad. Objective: To describe the clinical characteristics, autoantibodies status, and neurological outcome associated with anti-SRP antibody. Methods: We studied clinical and laboratory findings of 100 patients with inflammatory myopathy and anti-SRP antibodies. Anti-SRP antibodies in serum were detected by the presence of 7S RNA using RNA immunoprecipitation. In addition, enzyme-linked immunosorbent assays (ELISAs) using a 54-kD protein of SRP (SRP54) and 3-hydroxyl-3-methylglutatyl-coenzyme A reductase (HMGCR) were also conducted. Results: The mean onset age of the 61 female and 39 male patients was 51 years (range 4-82 years); duration ≥ 12 months before diagnosis was seen in 23 cases. All patients presented limbs weakness; 63 had severe weakness, 70 neck weakness, 41 dysphagia, and 66 muscle atrophy. Extramuscular symptoms and associated disorders were infrequent. Creatine kinase levels were mostly more than 1000 IU/L. Histological diagnosis showed 84 patients had necrotizing myopathy, and apparent cell infiltration was observed in 16 patients. Anti-SRP54 antibodies were undetectable in 18 serum samples with autoantibodies to 7S RNA. Anti-HMGCR antibodies were positive in 3 patients without the statin treatment, however, were negative in 5 patients with statin-exposure at disease onset. All but 3 patients were treated by corticosteroids and 62 (77 %) of these 81 patients required additional immunotherapy. After 2-years treatment, 22 (27 %) of these 81 patients had poor neurological outcomes with modified Rankin scale scores of 3-5. Multivariate analysis revealed that pediatric disease onset was associated with the poor outcomes. Conclusion: Anti-SRP antibodies are associated with different clinical courses and histological presentations.

AB - Background: Anti-signal recognition particle (SRP) antibodies are used as serological markers of necrotizing myopathy, which is characterized by many necrotic and regenerative muscle fibers without or with minimal inflammatory cell infiltration. The clinical spectrum associated with anti-SRP antibodies seems to be broad. Objective: To describe the clinical characteristics, autoantibodies status, and neurological outcome associated with anti-SRP antibody. Methods: We studied clinical and laboratory findings of 100 patients with inflammatory myopathy and anti-SRP antibodies. Anti-SRP antibodies in serum were detected by the presence of 7S RNA using RNA immunoprecipitation. In addition, enzyme-linked immunosorbent assays (ELISAs) using a 54-kD protein of SRP (SRP54) and 3-hydroxyl-3-methylglutatyl-coenzyme A reductase (HMGCR) were also conducted. Results: The mean onset age of the 61 female and 39 male patients was 51 years (range 4-82 years); duration ≥ 12 months before diagnosis was seen in 23 cases. All patients presented limbs weakness; 63 had severe weakness, 70 neck weakness, 41 dysphagia, and 66 muscle atrophy. Extramuscular symptoms and associated disorders were infrequent. Creatine kinase levels were mostly more than 1000 IU/L. Histological diagnosis showed 84 patients had necrotizing myopathy, and apparent cell infiltration was observed in 16 patients. Anti-SRP54 antibodies were undetectable in 18 serum samples with autoantibodies to 7S RNA. Anti-HMGCR antibodies were positive in 3 patients without the statin treatment, however, were negative in 5 patients with statin-exposure at disease onset. All but 3 patients were treated by corticosteroids and 62 (77 %) of these 81 patients required additional immunotherapy. After 2-years treatment, 22 (27 %) of these 81 patients had poor neurological outcomes with modified Rankin scale scores of 3-5. Multivariate analysis revealed that pediatric disease onset was associated with the poor outcomes. Conclusion: Anti-SRP antibodies are associated with different clinical courses and histological presentations.

KW - Autoantibodies

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KW - Outcome

KW - RNA immunoprecipitation

KW - Signal recognition particle

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