Highly multiplexed imaging mass cytometry identifies similarities between antisynthetase syndrome and dermatomyositis skin lesions

Liver Involvement is Associated with Higher Risk of Rapidly Progressive Interstitial Lung Disease and Mortality in Anti-Melanoma Differentiation-Associated Gene 5 Antibody- Positive Dermatomyositis

Purpose

This study aimed to assess liver involvement and investigate its correlation with rapidly progressive interstitial lung disease (RP-ILD) and mortality in anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5 positive) DM patients.

Patients and Methods

This retrospective study included 159 patients diagnosed with anti-MDA5 positive DM or anti-synthetase syndrome (ASyS). Clinical features and laboratory findings were compared between patients with anti-MDA5 positive DM and patients with ASyS. In the anti-MDA5 positive DM cohort, clinical features and laboratory findings between patients with liver involvement and without liver involvement were further compared. The effects of liver involvement on the overall survival (OS) and development of RP-ILD were also analyzed using Kaplan-Meier method and Cox regression analysis.

Results

Levels of serum aspartate aminotransferase (AST), alanine transaminase (ALT), γ-glutamyl transferase (γGT) and alkaline phosphatase (ALP) were all significantly higher in patients with anti-MDA5 positive DM than those in patients with ASyS. In our cohort of anti-MDA5 positive DM patents, 31 patients (34.4%) were complicated with liver involvement. Survival analysis revealed that serum ferritin >1030.0 ng/mL (p<0.001), ALT >103.0 U/l (p<0.001), AST >49.0 U/l (p<0.001), γGT >82.0 U/l (p<0.001), ALP >133.0 U/l (p<0.001), lactate dehydrogenase (LDH)>474.0 U/l (p<0.001), plasma albumin (ALB) <35.7 g/l (p<0.001) and direct bilirubin (DBIL) >2.80 μmol/l (p=0.002) predicted poor prognosis. The incidence of RP-ILD increased remarkably in patients with liver involvement compared to patients without liver involvement (58.1% vs 22.0%, p=0.001). Multivariate analysis revealed that elevated serum ALT level was an independent risk factor for mortality (HR 6.0, 95% CI 2.3, 16.2, p<0.001) and RP-ILD (HR 5.9, 95% CI 2.2, 15.9, p<0.001) in anti-MDA5 positive DM patents.

Conclusion

Liver involvement is common in patients with anti-MDA5 positive DM. Elevated serum ALT level was an independent risk factor for RP-ILD and mortality in patients with anti-MDA5 positive DM.

Interferon type I signature associated with skin disease in juvenile dermatomyositis

Background

Interferon type I (IFN-I) signaling system hyperactivation plays an important role in the pathogenesis of juvenile dermatomyositis (JDM).

Aim of the study

To analyze IFN-I score with disease activity in patients with JDM.

Materials and methods

Clinical manifestations laboratory data, and treatment options were analyzed in 15 children with JDM. Disease activity was assessed by CMAS (childhood myositis assessment tool) and CAT (cutaneous assessment tool) scores. IFN I-score was assessed by RT-PCR quantitation of 5 IFN I-regulated transcripts (IFI44L, IFI44, IFIT3, LY6E, MXA1).

Results

All patients had skin and muscle involvement, some had a fever (n = 8), swallowing disorders (n = 4), arthritis (n = 5), calcinosis (n = 3), lipodystrophy (n = 2), and interstitial lung disease (n = 5). Twelve patients had elevated IFN I-score and it was correlated with skin disease activity. Ten patients had clinically active disease and the level of IFN I-score and its components were higher than in patients with inactive disease (8.8 vs. 4.2, p = 0.011). IFN I-score was evaluated in nine patients during follow-up. The simultaneous reduction of IFN I-score and its components, CMAS and CAT scores was observed.

Conclusion

Skin involvement in refractory JDM is a challenging problem requiring the use of additional medications. Serum IFN I-score might be suggested as the promising biomarker of skin disease activity in JDM patients. Further investigations on patients with JDM and recurrent disease activity are needed, especially concerning biomarkers that determine the response to JAK inhibitors and treatment options for patients who don't respond to them.

Imaging mass cytometry reveals tissue-specific cellular immune phenotypes in the mouse knee following ACL injury

Objective

To develop an imaging mass cytometry method for identifying complex cell phenotypes, inter-cellular interactions, and population changes in the synovium and infrapatellar fat pad (IFP) of the mouse knee following a non-invasive compression injury.

Design

Fifteen male C57BL/6 mice were fed a high-fat diet for 8 weeks prior to random assignment to sham, 0.88 ​mm, or 1.7 ​mm knee compression displacement at 24 weeks of age. 2-weeks after loading, limbs were prepared for histologic and imaging mass cytometry analysis, focusing on myeloid immune cell populations in the synovium and IFP.

Results

1.7 ​mm compression caused anterior cruciate ligament (ACL) rupture, development of post-traumatic osteoarthritis, and a 2- to 3-fold increase in cellularity of synovium and IFP tissues compared to sham or 0.88 ​mm compression. Imaging mass cytometry identified 11 myeloid cell subpopulations in synovium and 7 in IFP, of which approximately half were elevated 2 weeks after ACL injury in association with the vasculature. Notably, two monocyte/macrophage subpopulations and an MHC IIhi population were elevated 2-weeks post-injury in the synovium but not IFP. Vascular and immune cell interactions were particularly diverse in the synovium, incorporating 8 unique combinations of 5 myeloid cell populations, including a monocyte/macrophage population, an MHC IIhi population, and 3 different undefined F4/80+ myeloid populations.

Conclusions

Developing an imaging mass cytometry method for the mouse enabled us to identify a diverse array of synovial and IFP vascular-associated myeloid cell subpopulations. These subpopulations were differentially elevated in synovial and IFP tissues 2-weeks post injury, providing new details on tissue-specific immune regulation.

Type I Interferons in Autoimmunity: Implications in Clinical Phenotypes and Treatment Response

Type I interferon (IFN-I) is thought to play a role in many systemic autoimmune diseases. IFN-I pathway activation is associated with pathogenic features, including the presence of autoantibodies and clinical phenotypes such as more severe disease with increased disease activity and damage. We will review the role and potential drivers of IFN-I dysregulation in 5 prototypic autoimmune diseases: systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, primary Sjögren syndrome, and systemic sclerosis. We will also discuss current therapeutic strategies that directly or indirectly target the IFN-I system.