Myositis in systemic lupus erythematosus

Myositis: A Rare First Presentation of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects multiple systems with a variety of clinical manifestations and serological abnormalities. Overt myositis is a rare and not well-studied manifestation of SLE, which is associated with a more severe disease course and may be overlooked by clinicians. This case report describes a rare first presentation of SLE with myositis. An 18-year-old female patient presented with a three-month history of generalized muscle weakness, polyarthralgia, and rashes. Physical examination revealed malar rash, a dry scaly pigmented rash affecting the flanks, and a non-blanching purpuric rash with mottled discoloration and a well-defined ulceration, affecting both hands, suggestive of vasculitis. A pigmented atrophic patch on the right upper chest was also suggestive of discoid lupus. Further examination findings included bilateral upper and lower limb weakness affecting proximal muscles (Medical Research Council (MRC) grade 3/5) more than the distal muscles (MRC grade 4/5). The patient's investigation panel revealed leukopenia, anemia, elevated liver enzymes, and elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) as well as significant elevation in creatinine kinase. Further antibody testing revealed positive antinuclear antibodies (ANA), anti-double-stranded DNA (anti-dsDNA), anti-Smith, and anti-U1-ribonucleoprotein (U1RNP), along with electrodiagnostic study supporting the diagnosis of SLE complicated by myositis and vasculitis. Treatment was initiated with prednisolone, hydroxychloroquine, methotrexate, folic acid, and omeprazole with sunscreen. Over the next several months, the patient demonstrated significant clinical and laboratory improvement, regaining full muscle power, with her vasculitis rash also improving and steroid tapering initiated to avoid side effects. This case highlights the importance of recognizing myositis as a rare potential first presentation of SLE and the need for heightened clinical awareness as early diagnosis and treatment is vital for improving long-term outcomes. This case adds to the existing literature and provides a reference for future clinical encounters with such complex cases.

Immune-mediated necrotizing myopathy with concomitant development of Kikuchi-Fujimoto disease

Immune-mediated necrotizing myopathy (IMNM) is a distinct type of idiopathic inflammatory myositis, pathologically characterized by myofiber necrosis and degeneration in the absence of lymphocyte infiltration. Herein, we present a case of IMNM with concomitant development of Kikuchi-Fujimoto disease (KFD), characterized by histiocytic necrotizing lymphadenitis, in a 36-year-old woman who had a treatment history for rheumatoid arthritis (RA). Treatment with oral prednisolone and tacrolimus as immunosuppressants resulted in the remission of the skeletomuscular involvement and lymphadenopathy. To the best of our knowledge, this is the first report of IMNM and KFD developing concomitantly during the clinical course of RA.

Joint and muscle inflammatory disease: A scoping review of the published evidence

OBJECTIVES

Polyarthritis is commonly reported in idiopathic inflammatory myositis patients, but few studies have focused on the overlap of myositis with rheumatoid arthritis which is a difficult diagnosis in the absence of well-defined diagnostic criteria. The primary objective of this scoping review was to map the field of research to explore the potential diagnoses in patients presenting with both myositis and polyarthritis.

METHODS

Two electronic databases (MEDLINE/PubMed® and Web of Science®) were systematically searched using the terms (myositis OR 'inflammatory idiopathic myopathies') AND (polyarthritis OR 'rheumatoid arthritis') without any publication date limit.

RESULTS

Among individual records, 280 reports met inclusion criteria after full-text review. There was heterogeneity in the definition of overlap myositis as well as the characteristics of rheumatoid arthritis. In many studies, key data were lacking; rheumatoid factor status was reported in 56.8% (n=151), anti-citrullinated proteins antibodies status in 18.8% (n=50), and presence or absence of bone erosions in 45.1% (n=120) of the studies. Thirteen different diagnoses were found to associate myositis with polyarthritis: antisynthetase syndrome (29.6%, n=83), overlap myositis with rheumatoid arthritis (16.1%, n=45), drug-induced myositis (20.0%, n=56), rheumatoid myositis (7.5%, n=21), inclusion body myositis (1.8%, n=5), overlap with connective tissue disease (20.0%, n=56), and others (5.0%, n=14).

CONCLUSION

The spectrum of joint and muscle inflammatory diseases encompasses many diagnoses including primitive and secondary myositis associated with RA or arthritis mimicking RA. This review highlights the need for a consensual definition of OM with RA to better individualise this entity from the numerous differential diagnoses.

Two clusters of systemic lupus erythematosus patients with muscle involvement in a Chinese cohort

OBJECTIVES

This study aimed to depict the clinical features, including myositis specific or associated antibody (MSA/MAA) profile of systemic lupus erythematosus (SLE) patients with muscle involvement in a Chinese cohort.

METHODS

We retrospectively studied a cohort of 1696 SLE inpatients and screened for concurrent myositis features from January 2013 to June 2021. Propensity score matching was applied to enroll controls without myositis features from our cohort. Demographic, clinical and laboratory variables were collected. MSA/MAA panels containing 16 autoantibodies (TIF1-γ, MDA5, NXP2, Mi-2α/β, SAE1, Jo-1, PL-7, PL-12, EJ, OJ, SRP, HMGCR, cN-1A, PM-Scl75/100, Ku and Ro52) were tested by line-blotting assay. Binary logistic regression and K-means clustering were applied.

RESULTS

Forty-one of 1696 (2.42%) SLE patients in our SLE inpatient cohort showed features of myositis. Binary logistic regression revealed that new-onset SLE (odds ratio [OR] = 4.77, 95% CI = 1.10-20.57), interstitial lung disease (ILD) (OR = 10.07, 95% CI = 1.65-61.51), positive anti-U1RNP antibody (OR = 4.38, 95% CI = 1.08-17.75), and Raynaud's phenomenon (OR = 7.94, 95% CI = 1.41-44.69) were associated with muscle involvement. Except for anti-Ro52 (50%), anti-Ku antibody (38.2%) was the next frequently detected MSA/MAA in the panel, followed by anti-NXP2 antibody (11.8%). It was noteworthy that multiple MSA/MAAs (≥2, excluding anti-Ro52) coexisted in 9 patients. Patients with myositis features were clustered into 2 subgroups. Cluster 1 was characterized by anti-Ku or anti-Ro52 with high SLE Disease Activity Index, whereas cluster 2 presented with anti-U1RNP, Raynaud's phenomenon and pulmonary arterial hypertension resembling mixed connective tissue disease.

CONCLUSION

In our Chinese SLE inpatient cohort, muscle involvement was infrequent. Nevertheless, distinct features in these SLE patients deserve further study.

Muscle involvement in systemic lupus erythematosus: multimodal ultrasound assessment and relationship with physical performance

OBJECTIVES

The objectives of this study were (1) to explore US findings for muscle mass, muscle quality and muscle stiffness in SLE patients and healthy subjects; (2) to investigate the relationship between the US muscle findings and physical performance in SLE patients and healthy subjects.

METHODS

Quadriceps muscle thickness was used for assessment of muscle mass, muscle echogenicity (using a visual semi-quantitative scale and grayscale analysis with histograms) for assessment of muscle quality, and point shear-wave elastography (SWE) for assessment of muscle stiffness in 30 SLE patients (without previous/current myositis or neuromuscular disorders) and 15 age-, sex- and BMI-matched healthy subjects. Hand grip strength tests and short physical performance battery (SPPB) tests were carried out in the same populations.

RESULTS

No difference was observed between SLE patients and healthy subjects for quadriceps muscle thickness (35.2 mm ±s.d. 6.8 vs 34.8 mm ± s.d. 6.0, respectively, P = 0.79). Conversely, muscle echogenicity was significantly increased in SLE patients (visual semi-quantitative scale: 1.7 ± s.d. 1.0 vs 0.3 ± s.d. 0.5, respectively, P < 0.01; grayscale analysis with histograms: 87.4 mean pixels ± s.d. 18.8 vs 70.1 mean pixels ± s.d. 14.0, respectively, P < 0.01). Similarly, SWE was significantly lower in SLE patients compared with healthy subjects {1.5 m/s [interquartile range (IQR) 0.3] vs 1.6 m/s (IQR 0.2), respectively, P = 0.01}. Muscle echogenicity was inversely correlated with grip strength (visual semi-quantitative scale, Rho: -0.47, P = 0.01; grayscale analysis with histograms, Rho: -0.41, p < 0.01) and SPPB (visual semi-quantitative scale, Rho: -0.50, P < 0.01; grayscale analysis with histograms Rho: -0,46, P < 0.01).

CONCLUSIONS

US assessment of muscle echogenicity and stiffness is useful for the early detection of muscle involvement in SLE patients.

Serologic phenotypes distinguish systemic lupus erythematosus patients developing interstitial lung disease and/or myositis

Objectives

To determine if serologic phenotypes could be identified in systemic lupus erythematosus patients developing interstitial lung disease (ILD) and/or myositis.

Methods

Adult SLE patients (without myositis/ILD at baseline) had annual assessments and serum sampling between 2000 and 2017. New-onset ILD was identified using the SDI pulmonary fibrosis item. New-onset myositis was identified using the SLICC Damage Index muscle atrophy/weakness item, the SLEDAI-2K item for myositis, and annual creatinine kinase testing. Chart review confirmed ILD/myositis cases and randomly sampled SLE patients from baseline formed our sub-cohort (N = 72). Cases and sub-cohort were compared regarding myositis-related biomarkers at baseline and at a randomly selected follow-up between baseline and end of observation (date of ILD/myositis diagnosis or Dec. 31, 2017). Descriptive analyses and hazards ratios (HRs) were generated for ILD/myositis incidence, focusing on baseline serology and adjusting for sex, race/ethnicity, age at SLE diagnosis, and SLE duration.

Results

Fourteen SLE patients developed ILD (N = 9), myositis (N = 3), and/or both (N = 2). Thirteen of those (92.9%) developing ILD/myositis had at least one biomarker at baseline, versus 47 (65.3%) SLE patients who never developed myositis/ILD. The most common biomarkers in myositis/ILD were KL-6, anti-Ro52, and anti-Ku. Baseline biomarkers tended to remain positive in follow-up. In multivariate Cox regressions, SLE patients had higher risk of developing myositis/ILD with elevated baseline KL-6 (adjusted hazard ratio 3.66; 95% confidence interval 1.01, 13.3). When updating biomarkers over time, we also saw correlations between anti-Smith and ILD/myositis.

Conclusions

Baseline myositis-related biomarkers were highly associated with ILD/myositis incidence. This is the first identification of biomarker phenotypes with ILD/myositis risk in SLE.

Clinical and histopathological features of myositis in systemic lupus erythematosus

Objective

The objectives of this study were to compare the clinical features of patients with SLE with and without myopathy and to describe the muscle biopsy features of patients with SLE myopathy.

Methods

This nested case–control study included all subjects enrolled in the Hopkins Lupus Cohort database from May 1987 to June 2016. Subjects with elevated creatine kinase along with evidence of muscle oedema on MRI, myopathic electromyography and/or myopathic muscle biopsy features were defined as having SLE myopathy. Demographic, serological and clinical features were compared between patients with SLE with and without myopathy. Muscle biopsies were histologically classified as polymyositis, dermatomyositis, necrotising myopathy or non-specific myositis.

Results

From among 2437 patients with SLE, 179 (7.3%) had myopathy. African American patients were more likely to develop myositis than Caucasian patients (p<0.0001). Compared with those without myopathy, patients with SLE myopathy were more likely to have malar rash (OR 1.67, 1.22–2.29), photosensitivity (OR 1.43, 1.04–1.96), arthritis (OR 1.81, 1.21–2.69), pleurisy (OR 1.77, 1.3–2.42), pericarditis (OR 1.49, 1.06–2.08), acute confusional state (OR 2.07, 1.09–3.94), lymphopaenia (OR 1.64, 1.2–2.24), anti-double-stranded DNA antibodies (OR 1.52, 1.09–2.13), lupus anticoagulant (OR 1.42, 1–2), cognitive impairment (OR 1.87, 1.12–3.13), cataract (OR 1.5, 1.04–2.18), pulmonary hypertension (OR 1.98, 1.13–3.47), pleural fibrosis (OR 2.01, 1.27–3.18), premature gonadal failure (OR 1.9, 1.05–3.43), diabetes (OR 1.92, 1.22–3.02) or hypertension (OR 1.45, 1.06–2). Among 16 muscle biopsies available for review, the most common histological classifications were necrotising myositis (50%) and dermatomyositis (38%).

Conclusions

Patients with SLE myopathy have a higher prevalence of numerous SLE disease manifestations. Necrotising myopathy and dermatomyositis are the most prevalent histopathological features in SLE myopathy.

Imaging of Joint and Soft Tissue Involvement in Systemic Lupus Erythematosus

PURPOSE OF REVIEW

To highlight the potential uses and applications of imaging in the assessment of the most common and relevant musculoskeletal (MSK) manifestations in systemic lupus erythematosus (SLE).

RECENT FINDINGS

Ultrasound (US) and magnetic resonance imaging (MRI) are accurate and sensitive in the assessment of inflammation and structural damage at the joint and soft tissue structures in patients with SLE. The US is particularly helpful for the detection of joint and/or tendon inflammation in patients with arthralgia but without clinical synovitis, and for the early identification of bone erosions. MRI plays a key role in the early diagnosis of osteonecrosis and in the assessment of muscle involvement (i.e., myositis and myopathy). Conventional radiography (CR) remains the traditional gold standard for the evaluation of structural damage in patients with joint involvement, and for the study of bone pathology. The diagnostic value of CR is affected by the poor sensitivity in demonstrating early structural changes at joint and soft tissue level. Computed tomography allows a detailed evaluation of bone damage. However, the inability to distinguish different soft tissues and the need for ionizing radiation limit its use to selected clinical circumstances. Nuclear imaging techniques are valuable resources in patients with suspected bone infection (i.e., osteomyelitis), especially when MRI is contraindicated. Finally, dual energy X-ray absorptiometry represents the imaging mainstay for the assessment and monitoring of bone status in patients with or at-risk of osteoporosis. Imaging provides relevant and valuable information in the assessment of MSK involvement in SLE.

The complex functions of microRNA-150 in allergy, autoimmunity and immune tolerance

<abstract> <p>At present, special efforts are being made to develop the strategies allowing for activation of long-lasting antigen-specific immune tolerance in therapy of allergic and autoimmune diseases. Some of these therapeutic approaches are aimed at modulating cell functions at genetic level by using miRNA-based and miRNA-targeting treatments. Simultaneously, the crucial role of extracellular vesicles as natural miRNA conveyors is highlighted for induction of antigen-specific immune tolerance, especially that they appear to be easily manipulatable for therapeutic applications. Among other immune-related miRNAs, miR-150 is getting special attention as it is differently expressed by immune cells at various stages of their maturation and differentiation. In addition, miR-150 is involved in different signaling cascades orchestrating humoral and cell-mediated mechanisms of both innate and adaptive immune responses. Therefore, miR-150 is considered a master regulator of immunity in mammals. Currently, physiological miR-150-dependent regulatory circuits and causes of their malfunctioning that underlie the pathogenesis of allergic and autoimmune disorders are being unraveled. Thus, present review summarizes the current knowledge of the role of miR-150 in the pathogenesis and complications of these diseases. Furthermore, the involvement of miR-150 in regulation of immune responses to allergens and self-antigens and in induction of antigen-specific immune tolerance is discussed with the special emphasis on the therapeutic potential of this miRNA.</p> </abstract>