Idiopathic inflammatory myopathies overlapping with systemic diseases

Therapeutic potential of natural killer cells in neuroimmunological diseases

Natural killer (NK) cells, a major component of the innate immune system, have prominent immunoregulatory, antitumor proliferation, and antiviral activities. NK cells act as a double-edged sword with therapeutic potential in neurological autoimmunity. Emerging evidence has identified NK cells are involved in the development and progression of neuroimmunological diseases such as multiple sclerosis, neuromyelitis optica spectrum disorders, autoimmune encephalitis, Guillain-Barré Syndrome, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis, and idiopathic inflammatory myopathy. However, the regulatory mechanisms and functional roles of NK cells are highly variable in different clinical states of neuroimmunological diseases and need to be further determined. In this review, we summarize the evidence for the heterogenic involvement of NK cells in the above conditions. Further, we describe cutting-edge NK-cell-based immunotherapy for neuroimmunological diseases in preclinical and clinical development and highlight challenges that must be overcome to fully realize the therapeutic potential of NK cells.

Shrinking lung syndrome mimicking diaphragmatic palsy in systemic lupus erythematosus

A 25-year-old woman presented with 1 year of progressive orthopnoea, initially explained as bilateral diaphragmatic paresis caused by seronegative myasthenia gravis. She required assisted ventilation and received pyridostigmine and corticosteroids. She had minimal (particularly proximal) symmetrical tetraparesis with apparent bilateral diaphragmatic weakness, but had normal sensation. Further investigation suggested an overlap myositis with shrinking lung syndrome from systemic lupus erythematosus. She improved following immunosuppression with pulse corticosteroids and rituximab, and at 3 months no longer needed bilevel positive airway pressure support.

Aminoacyl-tRNA synthetases in human health and disease

The Aminoacyl-tRNA Synthetases (aaRSs) are an evolutionarily ancient family of enzymes that catalyze the esterification reaction linking a transfer RNA (tRNA) with its cognate amino acid matching the anticodon triplet of the tRNA. Proper functioning of the aaRSs to create aminoacylated (or “charged”) tRNAs is required for efficient and accurate protein synthesis. Beyond their basic canonical function in protein biosynthesis, aaRSs have a surprisingly diverse array of non-canonical functions that are actively being defined. The human genome contains 37 genes that encode unique aaRS proteins. To date, 56 human genetic diseases caused by damaging variants in aaRS genes have been described: 46 are autosomal recessive biallelic disorders and 10 are autosomal dominant monoallelic disorders. Our appreciation of human diseases caused by damaging genetic variants in the aaRSs has been greatly accelerated by the advent of next-generation sequencing, with 89% of these gene discoveries made since 2010. In addition to these genetic disorders of the aaRSs, anti-synthetase syndrome (ASSD) is a rare autoimmune inflammatory myopathy that involves the production of autoantibodies that disrupt aaRS proteins. This review provides an overview of the basic biology of aaRS proteins and describes the rapidly growing list of human diseases known to be caused by genetic variants or autoimmune targeting that affect both the canonical and non-canonical functions of these essential proteins.

Characteristics and outcomes of overlap myositis: a comparative multigroup cohort study in adults from the MyoCite cohort

Overlap myositis (OM), an important subset of idiopathic inflammatory myopathies (IIM), is being increasingly recognized with wider myositis-specific autoantibody (MSA) testing. We studied the differences in clinical characteristics and long-term outcomes of OM with Dermatomyositis (DM), Polymyositis (PM), anti-synthetase syndrome (ASSD), and Cancer-associated IIM (CAM). Data from the MyoCite registry (Dec2017-May2020), a prospective dataset of IIM was extracted for the clinical profile, and MSAs, immunosuppressants received, disease activity (relapses and incomplete response), and treatment-related (drugs ADRs and infections) adverse events (DRAE and TRAE) were collected and analyzed between groups. Of 214 adults (58-OM,89-DM,27-ASSD,33-PM,7-CAM), OM had a greater female preponderance (13.5:1). Raynaud's and sclerodactyly were the prime distinguishing features of OM. OM could be distinguished from PM by frequent arthritis (OR-3.2) and infrequent dysphagia (OR-0.17); DM with greater nephritis (OR-20), infrequent dysphagia (OR-0.24) and rashes (OR-0.02); and ASSD by infrequent ILD (OR-0.07), and mechanic's hand (OR-0.05). 50% fulfilled the classification criteria for ASSD in the absence of MSA testing. ANA was positive more often (PM/DM: OR-6.7) and anti-Ro52 (OR-4.5) frequent in OM. Baseline serum creatinine and acute phase reactants were higher. OM received lower glucocorticoids (0 mg/kg, p < 0.001). Overall, 90% and 84% of OM at 12 and 24 months, respectively, achieved remission, with similar DRAE and TRAE as other IIM subsets. OM can be misdiagnosed as ASSD in the absence of MSA testing. Raynaud's, sclerodactyly, and a positive ANA may identify OM and prevent overtreatment.

Rhabdomyolysis as an initial presentation of systemic lupus erythematosus: a case report

BACKGROUND

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease which most commonly presents in women of reproductive age. It takes a relapsing-remitting course and may manifest as a variety of clinical symptoms, making it difficult to diagnose at first presentation, particularly in the emergency department (ED) setting. In active SLE, rhabdomyolysis has, thus far, not been reported as the sole initial presentation.

CASE PRESENTATION

A 28-year-old presented to the ED with bilateral proximal arm swelling and pain. She had a previous history of Raynaud's disease. Creatine kinase was > 13,000 units/l (normal range 25-200), but renal function was preserved. She did not require hospital admission so was encouraged to take oral fluids and discontinue the combined oral contraceptive pill. Antinuclear antibody and anti-double-stranded DNA titres were highly elevated with low complement demonstrated. She was diagnosed with SLE and treated with an oral prednisolone course. Antibody titres remained high 6 months later, provoking the initiation of hydroxychloroquine therapy.

CONCLUSIONS

We report with a view to recommend autoimmune screening in young patients for whom a cause of rhabdomyolysis is not clearly identified.

Lung adenocarcinoma and anti-transcriptional intermediary factor 1-gamma positive dermatomyositis complicated with spontaneous oesophageal rupture

A 58-year-old man presented with a two-month history of facial erythema and dry cough. Physical examination revealed typical cutaneous manifestations of dermatomyositis (DM), including heliotrope rash and shawl sign. A chest X-ray revealed a 4-cm mass in the right middle lung. After bronchoscopy and investigation of auto-antibodies, he was diagnosed with co-occurring transcriptional intermediary factor 1-gamma (TIF1-γ) positive DM and lung adenocarcinoma. He was administered oral prednisolone for subsequent muscle weakness, but developed TIF1-γ positive DM-associated oropharyngeal dysphagia complicated by spontaneous oesophageal rupture and died from progression of chemoresistant lung cancer.

[What's new in internal medicine?]

What's new in internal medicine will be dedicated to three topics: i) inflammatory myopathies constituting a heterogenous group of diseases whose clinical manifestations, immunological abnormalities, treatment response and outcomes vary widely; ii) alterations of gut microbiota contributing to the occurrence or development of a range of conditions, including autoimmune diseases for which further work is necessary to understand the correlation of dysbiosis with these diseases; iii) the reciprocal relationship between obesity, metabolic syndrome, atherosclerosis and autoimmune diseases. New data concerning systemic sclerosis, cutaneous vasculitis, adult Still's disease, autoantibodies anti DFS70, Epstein Barr virus and autoimmune diseases were also highlighted.