Genetic changes from type I interferons and JAK inhibitors: clues to drivers of juvenile dermatomyositis.

Objective: To better understand the pathogenesis of juvenile dermatomyositis (JDM), we examined the effect of the cytokines type I interferons (IFN I) and JAK inhibitor drugs (JAKi) on gene expression in bioengineered pediatric skeletal muscle.

Methods: Myoblasts from three healthy pediatric donors were used to create three-dimensional skeletal muscle units termed myobundles. Myobundles were treated with IFN I, either IFNα or IFNβ.

The impact of the COVID-19 pandemic on patients with juvenile idiopathic inflammatory myopathies.

Background: Throughout the COVID-19 pandemic, there have been concerns regarding the risks of infection in patients with autoimmune disease. In this study, we investigated the impact of the pandemic on patients with juvenile idiopathic inflammatory myopathies (JIIM).

Methods: Data were collected using a patient/caregiver survey via Research Electronic Data Capture (REDCap) database.

Effect of type I interferon on engineered pediatric skeletal muscle: a promising model for juvenile dermatomyositis.

Objective: To investigate pathogenic mechanisms underlying JDM, we defined the effect of type I IFN, IFN-α and IFN-β, on pediatric skeletal muscle function and expression of myositis-related proteins using an in vitro engineered human skeletal muscle model (myobundle).

Methods: Primary myoblasts were isolated from three healthy pediatric donors and used to create myobundles that mimic functioning skeletal muscle in structural architecture and physiologic function. Myobundles were exposed to 0, 5, 10 or 20 ng/ml IFN-α or IFN-β for 7 days and then functionally tested under electrical stimulation and analyzed immunohistochemically for structural and myositis-related proteins.

Calcinosis in juvenile dermatomyositis: Updates on pathogenesis and treatment.

Calcinosis, or the deposition of insoluble calcium salts in the skin, subcutaneous tissue, fascia, tendons, and muscles, is a feared complication of juvenile dermatomyositis. Calcinosis is estimated to affect up to 40% of patients with juvenile dermatomyositis and contributes to significant disease morbidity. Calcinosis can be challenging to treat, and the most effective treatment remains unknown because of a lack of comparative studies.

Gene Expression Profiles of Treatment Response and Non-Response in Children With Juvenile Dermatomyositis.

Objective: The study objective was to identify differences in gene expression between treatment responders (TRs) and treatment non-responders (TNRs) diagnosed with juvenile dermatomyositis (JDM).

Methods: Gene expression analyses were performed using whole blood messenger RNA sequencing in patients with JDM (n = 17) and healthy controls (HCs; n = 10). Four analyses were performed (A1-4) comparing differential gene expression and pathways analysis exploiting the timing of sample acquisition and the treatments received to perform these comparative analyses.

Metabolomics analysis identifies a lipidomic profile in treatment-naïve juvenile dermatomyositis patients vs healthy control subjects.

Objectives: To perform an exploratory study to identify a JDM serum metabolic profile that differs from healthy controls (HCs) and responds to immunosuppressive treatment.

Methods: Blood was collected from 9 HCs and 10 patients diagnosed with probable (n = 4) or definite (n = 6) JDM based on the criteria of Bohan and Peter for myositis, with 7 of the 10 providing longitudinal samples following initiation of treatment; these patients comprised the treatment-naïve cohort. Sera underwent mass spectroscopy-based measurements of targeted metabolic intermediates, including 15 amino acids, 45 acylcarnitines (ACs), 15 ceramides and 29 sphingomyelins.

Pilot Study of the Juvenile Dermatomyositis Consensus Treatment Plans: A CARRA Registry Study.

Objectives: To determine the feasibility of comparing the Childhood Arthritis and Rheumatology ResearchAlliance (CARRA) consensus treatment plans (CTP) in treating moderate new-onset juvenile dermatomyositis (JDM) using the CARRA registry, and to establish appropriate analytic methods to control for confounding by indication and missing data.

Methods: A pilot cohort of 39 patients with JDM from the CARRA registry was studied. Patients were assigned by the treating physician, considering patient/family preferences, to 1 of 3 CTP: methotrexate (MTX) and prednisone (MP); intravenous (IV) methylprednisolone, MTX, and prednisone (MMP); or IV methylprednisolone, MTX, prednisone, and IV immunoglobulin (MMPI).

Interferon Chemokine Score and Other Cytokine Measures Track With Changes in Disease Activity in Patients With Juvenile and Adult Dermatomyositis.

Objective: Our aim was to identify cytokines and chemokines in patients with adult dermatomyositis (DM) and juvenile dermatomyositis (JDM) that predict changes in disease activity.

Methods: Multiplexed immunoassays (Meso Scale Discovery) enabled simultaneous measurement of interferon (IFN)-regulated chemokines and other pro- and anti-inflammatory cytokines specific to differentiation of specific T-cell and innate pathways. Cytokine scores were computed for IFNCK (IP-10, MCP-1), Th1 (IFNɣ, TNFα, and IL2), Th2 (IL4, IL10, IL12, and IL 13), Th17 (IL6, IL17, IL1β), macrophage (MIP-1α, MIP-1β, IL8), and regulatory (IL10, TNFα) factors.

A Path to Prediction of Outcomes in Juvenile Idiopathic Inflammatory Myopathy.

Humans have an innate desire to observe and subsequently dissect an event into component pieces in an effort to better characterize the event. We then examine these pieces individually and in combinations using this information to determine the outcome of future similar events and the likelihood of their recurrence. Practically, this attempt to foretell an occurrence and predict its outcomes is evident in multiple disciplines ranging from meteorology to sociologic studies.

T Cell Receptor-Independent, CD31/IL-17A-Driven Inflammatory Axis Shapes Synovitis in Juvenile Idiopathic Arthritis.

T cells are considered autoimmune effectors in juvenile idiopathic arthritis (JIA), but the antigenic cause of arthritis remains elusive. Since T cells comprise a significant proportion of joint-infiltrating cells, we examined whether the environment in the joint could be shaped through the inflammatory activation by T cells that is independent of conventional TCR signaling. We focused on the analysis of synovial fluid (SF) collected from children with oligoarticular and rheumatoid factor-negative polyarticular JIA.

Consensus Treatment Plans for Chronic Nonbacterial Osteomyelitis Refractory to Nonsteroidal Antiinflammatory Drugs and/or With Active Spinal Lesions.

Objective: To develop standardized treatment regimens for chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis (CRMO), to enable comparative effectiveness treatment studies.

Methods: Virtual and face-to-face discussions and meetings were held within the CNO/CRMO subgroup of the Childhood Arthritis and Rheumatology Research Alliance (CARRA). A literature search was conducted, and CARRA membership was surveyed to evaluate available treatment data and identify current treatment practices.

The Regulatory B Cell Compartment Expands Transiently During Childhood and Is Contracted in Children With Autoimmunity.

Objective: Regulatory B cells that inhibit immune responses through interleukin-10 (IL-10) secretion (B10 cells) have been characterized in adult subjects with autoimmune disease. The aim of this study was to characterize B10 cells in individuals across the entire age range of normal human development and changes in their frequency and numbers in children with autoimmunity.

Methods: The phenotype and numbers of B10 cells in blood were examined in healthy individuals and children with autoimmunity, using flow cytometry.

Premature cell senescence and T cell receptor-independent activation of CD8+ T cells in juvenile idiopathic arthritis.

Objective: CD8+ T cells lacking CD28 were originally reported to be a characteristic feature of juvenile idiopathic arthritis (JIA), but the relevance of these unusual cells to this disease remains to be elucidated. Because of recent evidence that loss of CD28 cells is typical of terminally differentiated lymphocytes, the aim of this study was to examine functional subsets of CD8+ T cells in patients with JIA.

Methods: Blood and/or waste synovial fluid samples were collected from children with a definite diagnosis of JIA (n = 98).

Expansions of NK-like αβT cells with chronologic aging: novel lymphocyte effectors that compensate for functional deficits of conventional NK cells and T cells.

As the repertoire of αβT cell receptors (TCR) contracts with advancing age, there is an associated age-dependent accumulation of oligoclonal T cells expressing of a variety of receptors (NKR), normally expressed on natural killer (NK) cells. Evidences for differential regulation of expression of particular NKRs between T cells and NK cells suggest that NKR expression on T cells is physiologically programmed rather than a random event of the aging process. Experimental studies show NKRs on aged αβT cells may function either as independent receptors, and/or as costimulatory receptors to the TCR.