Corrigendum: Characteristics of cardiac involvement in immune-mediated necrotizing myopathy

[This corrects the article DOI: 10.3389/fimmu.2023.1094611.].

Juvenile idiopathic inflammatory myopathies with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase antibodies in a Chinese cohort

AIMS

To characterize the clinical and histopathological characteristics and treatment outcomes of juvenile idiopathic inflammatory myopathies (JIIMs) with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies in a Chinese cohort.

METHODS

We detected anti-HMGCR antibodies in a series of Chinese JIIM by ELISA and indirect immunofluorescence assay on HEK293 cells, and summarized the clinical findings of these anti-HMGCR antibody-positive patients.

RESULTS

Of 32 JIIM patients, 5 (15.63%) were found to be anti-HMGCR antibody-positive. The disease duration was 1.20 ± 0.45 months. Statin exposure was not found. Four patients had skin lesions, while typical pathological features of dermatomyositis such as perifascicular atrophy or myxovirus resistance protein A expression were not found. The mean creatine kinase level was 16771.60 U/L. Among the four patients who received long-term (10.46 ± 1.42 years) follow-up, three exhibited favorable outcomes with prednisone and additional immunosuppressants.

CONCLUSIONS

Our study indicates that anti-HMGCR antibodies may not be rare in Chinese JIIM. These anti-HMGCR-positive JIIMs were characterized by acute onset, substantially elevated creatine kinase level, and skin lesions without perifascicular changes in muscle pathology. The treatment outcome is generally favorable with the combination of steroid and immunosuppressant.

Efficacy and Safety of High-Dose Immunoglobulin-Based Regimen in Statin-Associated Autoimmune Myopathy: A Multi-Center and Multi-Disciplinary Retrospective Study

Statin-associated autoimmune myopathy is a rare muscle disorder, characterized by autoantibodies against HMGCR. The anti-HMGCR myopathy persists after statin, and often requires immunosuppressive therapy. However, there is not a standardized therapeutic approach. The purpose of this study is to report the effectiveness of the immunosuppressive treatment employed in a multi-center and multi-disciplinary cohort of patients affected by anti-HMGCR myopathy, in which an immunoglobulin (IVIG)-based treatment strategy was applied. We collected 16 consecutive patients with a diagnosis of anti-HMGCR myopathy, between 2012 and 2019, and recorded data on clinical and laboratory presentation (i.e., muscle strength, serum CK levels, and anti-HMGCR antibody titer) and treatment strategies. Our results highlight the safety and efficacy of an induction therapy combining IVIG with GCs and/or methotrexate to achieve persistent remission of the disease and steroid-free maintenance. Under IVIG-based regimens, clinical improvement and CK normalization occurred in more than two thirds of patients by six months. Relapse rate was low (3/16) and 2/3 relapses occurred after treatment suspension. Nearly 90% of the patients who successfully discontinued GCs were treated with a triple immunosuppressive regimen. In conclusion, an IVIG-based regimen, which particularly includes high-dose immunoglobulin, GCs and methotrexate, can provide a fast remission achievement with GC saving.

[Screening of autoantibodies associated with necrotizing myopathy among undiagnosed chronic myopathy]

We screened anti-signal recognition particle (SRP) and anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies among 42 patients who had undiagnosed chronic myopathy from six national hospitals. Anti-SRP and anti-HMGCR antibodies were determined by RNA immuneprecipitation and enzyme-linked immune-sorbent assay (ELISA), respectively. We identified two patients with anti-SRP antibodies (4.7%) and, two with anti-HMGCR antibodies (4.7%). Both of anti-SRP-positive patients showed dysphagia with a high level of creatine kinase. Anti-HMGCR antibodies were associated with mild muscle weakness with a relatively late disease onset. Our study suggests the importance of autoantibody testing among undiagnosed chronic myopathy.

An Unusual Case of Statin-Induced Myopathy: Anti-HMGCoA Necrotizing Autoimmune Myopathy

Statins are some of the most widely prescribed medications, and though generally well tolerated, can lead to a self-limited myopathy in a minority of patients. Recently, these medications have been associated with a necrotizing autoimmune myopathy (NAM). Statin-associated NAM is characterized by irritable myopathy on electromyography (EMG) and muscle necrosis with minimal inflammation on muscle biopsy. The case presented is a 63-year-old woman who has continued elevation of creatine kinase (CK) after discontinuation of statin therapy. She has irritable myopathy on EMG and NAM is confirmed by muscle biopsy. She subsequently tests positive for an experimental anti-3-hydroxy-3-methylglutaryl-coenzyme A (anti-HMGCoA) antibody that is found to be present in patients with statin-associated NAM. Though statin-associated NAM is a relatively rare entity, it is an important consideration for the general internist in patients who continue to have CK elevation and weakness after discontinuation of statin therapy. Continued research is necessary to better define statin-specific and dose-dependent risk, as well as optimal treatment for this condition.