Non-criteria antiphospholipid antibodies and calprotectin as potential biomarkers in pediatric antiphospholipid syndrome.

Our study aimed to evaluate the presence, clinical associations, and potential mechanistic roles of non-criteria antiphospholipid antibodies (aPL) and circulating calprotectin, a highly stable marker of neutrophil extracellular trap release (NETosis), in pediatric APS patients. We found that 79% of pediatric APS patients had at least one non-criteria aPL at moderate-to-high titer. Univariate logistic regression demonstrated that positive anti-beta-2 glycoprotein I domain 1 (anti-D1) IgG (p = 0.008), anti-phosphatidylserine/prothrombin (aPS/PT) IgG (p < 0.001), and aPS/PT IgM (p < 0.001) were significantly associated with venous thrombosis. Positive anti-D1 IgG (p < 0.001), aPS/PT IgG (p < 0.001), and aPS/PT IgM (p = 0.001) were also associated with non-thrombotic manifestations of APS, such as thrombocytopenia. Increased levels of calprotectin were detected in children with APS. Calprotectin correlated positively with absolute neutrophil count (r = 0.63, p = 0.008) and negatively with platelet count (r = -0.59, p = 0.015). Mechanistically, plasma from pediatric APS patients with high calprotectin levels impaired platelet viability in a dose-dependent manner.

Impact of anakinra use on clinical outcomes in children with moderate or severe multisystem inflammatory syndrome in children: a propensity score matched retrospective cohort study.

BACKGROUND: The treatment of children with multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 infection involves immunomodulatory therapies such as IVIG and steroids. Anakinra, an interleukin-1 receptor inhibitor, has also been used, but its effectiveness is not established yet. As optimal regimens for MIS-C remain unknown, we aimed to assess the effect of anakinra in reducing hospital stay in patients with MIS-C. METHODS: We included children admitted from May 2020 to May 2021 diagnosed with MIS-C based on CDC criteria. The exposure of interest was anakinra use at any point during admission. The anakinra exposed group and the anakinra unexposed group were propensity score matched based on demographic and clinical severity indicators at initial presentation. Our primary outcome was length of hospital stay. Secondary outcomes were duration of vasoactive support, vasoactive inotropic score (VIS), level of respiratory support, time to fever resolution, reduction of CRP levels, and length of ICU stay. We used Wilcoxon rank sum, t-test, Chi square and Fisher's exact tests. RESULTS: Of 138 children diagnosed with MIS-C, 79% had moderate or severe illness and 41% received anakinra. Of those, 31 patients who received anakinra were propensity score matched to 31 who did not. The length of stay in the hospital but not in the ICU was longer in the anakinra group. There were no differences in median duration of vasoactive support, fever resolution, CRP reduction, or VIS. CONCLUSIONS: In patients with moderate to severe MIS-C, use of anakinra was associated with longer duration of hospital stay.

An unconventional mechanism of IL-1ß secretion that requires Type I IFN in lupus monocytes.

Systemic Lupus Erythematosus (SLE) is characterized by autoreactive B cell activation, upregulation of Type I Interferon (IFN) and widespread inflammation. Mitochondrial nucleic acids (NAs) are increasingly recognized as triggers of IFN 1 . Thus, defective removal of mitochondria from mature red blood cells (Mito + RBCs), a feature of SLE, contributes to IFN production by myeloid cells 2 . Here we identify blood monocytes (Mo) that have internalized RBCs and co-express IFN-stimulated genes (ISGs) and interleukin-1ß (IL-1ß) in SLE patients with active disease. We show that ISG expression requires the interaction between Mito + RBC-derived mitochondrial DNA (mtDNA) and cGAS, while IL-1ß production entails Mito + RBC-derived mitochondrial RNA (mtRNA) triggering of RIG-I-like receptors (RLRs). This leads to the cytosolic release of Mo-derived mtDNA that activates the NLRP3 inflammasome. Importantly, IL-1ß release depends on the IFN-inducible myxovirus resistant protein 1 (MxA), which enables the translocation of this cytokine into a trans-Golgi network (TGN)-mediated unconventional secretory pathway. Our study highlights a novel and synergistic pathway involving IFN and the NLRP3 inflammasome in SLE.

Association of Juvenile Dermatomyositis Disease Activity With the Expansion of Blood Memory B and T Cell Subsets Lacking Follicular Markers.

OBJECTIVE: This study was undertaken to identify blood markers of juvenile dermatomyositis (DM) disease activity (DA), which are needed to improve disease management. METHODS: The study comprised a total of 123 juvenile DM patients and 53 healthy controls. Results of laboratory tests (aldolase, creatinine kinase, lactate dehydrogenase [LDH], aspartate aminotransferase) and clinical measures of DA in patients with juvenile DM, including the Manual Muscle Testing in 8 muscles (MMT-8), Childhood Myositis Assessment Scale (CMAS), and disease activity scores (DAS) (total DAS for juvenile DM, the muscle DAS, and the skin DAS), were recorded when available. Surface phenotype of peripheral blood mononuclear cells was assessed using flow cytometry. Whole blood transcriptional profiles were studied using either RNA-sequencing or microarrays. Differential gene expression was determined using DESeq and compared by pathway and gene ontology analyses. RESULTS: Conventional memory (CD27+IgD-) B cells expressing low CXCR5 levels (CXCR5low/- CM B cells) were significantly increased in frequency and absolute numbers in 2 independent cohorts of juvenile DM patients compared with healthy controls. The frequency of CD4+ Th2 memory cells (CD45RA-CXCR5-CCR6-CXCR3-) was also increased in juvenile DM, especially in patients who were within <1 year from diagnosis. The frequency of CXCR5low/- CM B cells correlated with serum aldolase levels and with a blood interferon-stimulated gene transcriptional signature. Furthermore, both the frequency and absolute numbers of CXCR5low/- CM B cells correlated with clinical and laboratory measures of muscle DA (MMT-8, CMAS, aldolase, and LDH). CONCLUSION: These findings suggest that both CM B cells lacking the CXCR5 follicular marker and CXCR5- Th2 cells represent potential biomarkers of DA in juvenile DM and may contribute to its pathogenesis.

Therapeutic recreation camps for youth with childhood-onset systemic lupus erythematosus: perceived psychosocial benefits.

BACKGROUND: The psychosocial burden of having a chronic disease can be substantial for adolescents with childhood-onset systemic lupus erythematosus (cSLE). Current literature is scarce on interventions that can improve psychosocial outcomes for this population. Therapeutic recreation camps have been proposed as a beneficial experience for chronically ill pediatric populations. However, their effective components have not been well characterized in patients with cSLE. In this study, we sought to understand the various components of the camp experience for adolescents with cSLE from both the patient and parent perspective. METHODS: We recruited patients with cSLE who had participated in one or more annual, weekend-long recreational lupus camp(s) near Dallas, Texas. Semi-structured in-depth telephone interviews were conducted from March-June 2020 with both the patients and parents. Questions focused on overall patient experience, psychosocial impact of camp participation, coping skills gained, and opportunities to prepare for the transition from pediatric to adult care. Interviews were coded and analyzed using inductive thematic analysis. RESULTS: We interviewed 9 current and former campers (ages 16-24), including a current camp counselor, and 3 of their parents separately. Reported benefits included a positive impact on social support through peer bonding, opportunities to develop coping mechanisms through structured activities and peer/medical staff interactions, opportunities for education about the cSLE disease experience, improved adherence through peer modeling, overall increase in self-efficacy, and better parental insight into the patient experience. Participants also provided suggestions for expansion and improvement in program development to optimize educational opportunities for both campers and parents. In addition, they advocated for longitudinal social support and community building. CONCLUSIONS: In this qualitative study, in which cSLE patients and their parents reflected on their experiences with therapeutic recreation camps, we found several perceived benefits impacting the patient and parent experience. Participants expressed a desire for more educational opportunities that could contribute to their successful transition from pediatric to adult care. Further studies are needed to demonstrate the effects of therapeutic recreation camps on the psychosocial health of this population.

"You Just Have to Keep Going, You Can't Give Up": Coping mechanisms among young adults with lupus transferring to adult care.

INTRODUCTION: Coping mechanisms and emotional regulation are important contributors to psychosocial health during stressful life events. We sought to describe the coping and emotional responses of persons with childhood-onset systemic lupus erythematosus during the transfer from pediatric to adult healthcare. METHODS: Semi-structured in-depth one-on-one interviews were conducted with 13 young women aged 18-24 of minority background who had transferred to adult care in a public hospital system. Thematic analysis was used to identify themes motifs from the data. RESULTS: Participants described the use of (1) problem-focused coping such as the use of clear communication and self-education, (2) adaptive emotion-focused coping such as cognitive reframing and acceptance, (3) social coping including support-seeking, (4) meaning-making coping including positive religious framing and viewing events as learning opportunities for growth, and (5) disengaged coping including denial and social isolation. A range of emotional responses associated with the transfer were described including fear, anger, loss, and feelings of empowerment and excitement. CONCLUSION: Effective coping and emotional regulation are modifiable factors that may impact transfer-related outcomes and psychosocial health. Addressing coping mechanisms is relevant to the optimized transfer to adult care.

Erythroid mitochondrial retention triggers myeloid-dependent type I interferon in human SLE.

Emerging evidence supports that mitochondrial dysfunction contributes to systemic lupus erythematosus (SLE) pathogenesis. Here we show that programmed mitochondrial removal, a hallmark of mammalian erythropoiesis, is defective in SLE. Specifically, we demonstrate that during human erythroid cell maturation, a hypoxia-inducible factor (HIF)-mediated metabolic switch is responsible for the activation of the ubiquitin-proteasome system (UPS), which precedes and is necessary for the autophagic removal of mitochondria. A defect in this pathway leads to accumulation of red blood cells (RBCs) carrying mitochondria (Mito+ RBCs) in SLE patients and in correlation with disease activity. Antibody-mediated internalization of Mito+ RBCs induces type I interferon (IFN) production through activation of cGAS in macrophages. Accordingly, SLE patients carrying both Mito+ RBCs and opsonizing antibodies display the highest levels of blood IFN-stimulated gene (ISG) signatures, a distinctive feature of SLE.

Novel homozygous variant in WISP3 in a family with unrecognized progressive pseudorheumatoid dysplasia.

We present the use of whole-genome sequencing to correctly diagnose progressive pseudorheumatoid dysplasia in patients with atypical clinical and radiologic findings and prior diagnosis of juvenile idiopathic arthritis.

A CD4+ T cell population expanded in lupus blood provides B cell help through interleukin-10 and succinate.

Understanding the mechanisms underlying autoantibody development will accelerate therapeutic target identification in autoimmune diseases such as systemic lupus erythematosus (SLE)1. Follicular helper T cells (TFH cells) have long been implicated in SLE pathogenesis. Yet a fraction of autoantibodies in individuals with SLE are unmutated, supporting that autoreactive B cells also differentiate outside germinal centers2. Here, we describe a CXCR5-CXCR3+ programmed death 1 (PD1)hiCD4+ helper T cell population distinct from TFH cells and expanded in both SLE blood and the tubulointerstitial areas of individuals with proliferative lupus nephritis. These cells produce interleukin-10 (IL-10) and accumulate mitochondrial reactive oxygen species as the result of reverse electron transport fueled by succinate. Furthermore, they provide B cell help, independently of IL-21, through IL-10 and succinate. Similar cells are generated in vitro upon priming naive CD4+ T cells with plasmacytoid dendritic cells activated with oxidized mitochondrial DNA, a distinct class of interferogenic toll-like receptor 9 ligand3. Targeting this pathway might blunt the initiation and/or perpetuation of extrafollicular humoral responses in SLE.

Personalized Immunomonitoring Uncovers Molecular Networks that Stratify Lupus Patients.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by loss of tolerance to nucleic acids and highly diverse clinical manifestations. To assess its molecular heterogeneity, we longitudinally profiled the blood transcriptome of 158 pediatric patients. Using mixed models accounting for repeated measurements, demographics, treatment, disease activity (DA), and nephritis class, we confirmed a prevalent IFN signature and identified a plasmablast signature as the most robust biomarker of DA. We detected gradual enrichment of neutrophil transcripts during progression to active nephritis and distinct signatures in response to treatment in different nephritis subclasses. Importantly, personalized immunomonitoring uncovered individual correlates of disease activity that enabled patient stratification into seven groups, supported by patient genotypes. Our study uncovers the molecular heterogeneity of SLE and provides an explanation for the failure of clinical trials. This approach may improve trial design and implementation of tailored therapies in genetically and clinically complex autoimmune diseases. PAPERCLIP.

IFN priming is necessary but not sufficient to turn on a migratory dendritic cell program in lupus monocytes.

Blood monocytes from children with systemic lupus erythematosus (SLE) behave similar to dendritic cells (DCs), and SLE serum induces healthy monocytes to differentiate into DCs in a type I IFN-dependent manner. In this study, we found that these monocytes display significant transcriptional changes, including a prominent IFN signature, compared with healthy controls. Few of those changes, however, explain DC function. Exposure to allogeneic T cells in vitro reprograms SLE monocytes to acquire DC phenotype and function, and this correlates with both IFN-inducible (IP10) and proinflammatory cytokine (IL-1ß and IL6) expression. Furthermore, we found that both IFN and SLE serum induce the upregulation of CCR7 transcription in these cells. CCR7 protein expression, however, requires a second signal provided by TLR agonists such as LPS. Thus, SLE serum "primes" a subset of monocytes to readily (<24 h) respond to TLR agonists and acquire migratory DC properties. Our findings might explain how microbial infections exacerbate lupus.

Increased sensitivity of the European medicines agency algorithm for classification of childhood granulomatosis with polyangiitis.

OBJECTIVE: Granulomatosis with polyangiitis (Wegener's; GPA) and other antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are rare in childhood and are sometimes difficult to discriminate. We compared use of adult-derived classification schemes for GPA against validated pediatric criteria in the ARChiVe (A Registry for Childhood Vasculitis e-entry) cohort, a Childhood Arthritis and Rheumatology Research Alliance initiative. METHODS: Time-of-diagnosis data for children with physician (MD) diagnosis of AAV and unclassified vasculitis (UCV) from 33 US/Canadian centers were analyzed. The European Medicines Agency (EMA) classification algorithm and European League Against Rheumatism/Paediatric Rheumatology International Trials Organisation/Paediatric Rheumatology European Society (EULAR/PRINTO/PRES) and American College of Rheumatology (ACR) criteria for GPA were applied to all patients. Sensitivity and specificity were calculated (MD-diagnosis as reference). RESULTS: MD-diagnoses for 155 children were 100 GPA, 25 microscopic polyangiitis (MPA), 6 ANCA-positive pauciimmune glomerulonephritis, 3 Churg-Strauss syndrome, and 21 UCV. Of these, 114 had GPA as defined by EMA, 98 by EULAR/PRINTO/PRES, and 87 by ACR. Fourteen patients were identified as GPA by EULAR/PRINTO/PRES but not by ACR; 3 were identified as GPA by ACR but not EULAR/PRINTO/PRES. Using the EMA algorithm, 135 (87%) children were classifiable. The sensitivity of the EMA algorithm, the EULAR/PRINTO/PRES, and ACR criteria for classifying GPA was 90%, 77%, and 69%, respectively, with specificities of 56%, 62%, and 67%. The relatively poor sensitivity of the 2 criteria related to their inability to discriminate patients with MPA. CONCLUSION: EULAR/PRINTO/PRES was more sensitive than ACR criteria in classifying pediatric GPA. Neither classification system has criteria for MPA; therefore usefulness in discriminating patients in ARChiVe was limited. Even when using the most sensitive EMA algorithm, many children remained unclassified.

Assessing the performance of the Birmingham Vasculitis Activity Score at diagnosis for children with antineutrophil cytoplasmic antibody-associated vasculitis in A Registry for Childhood Vasculitis (ARChiVe).

OBJECTIVE: There are no validated tools for measuring disease activity in pediatric vasculitis. The Birmingham Vasculitis Activity Score (BVAS) is a valid disease activity tool in adult vasculitis. Version 3 (BVAS v.3) correlates well with physician's global assessment (PGA), treatment decision, and C-reactive protein in adults. The utility of BVAS v.3 in pediatric vasculitis is not known. We assessed the association of BVAS v.3 scores with PGA, treatment decision, and erythrocyte sedimentation rate (ESR) at diagnosis in pediatric antineutrophil cytoplasmic antibody-associated vasculitis (AAV). METHODS: Children with AAV diagnosed between 2004 and 2010 at all ARChiVe centers were eligible. BVAS v.3 scores were calculated with a standardized online tool (www.vasculitis.org). Spearman's rank correlation coefficient (r(s)) was used to test the strength of association between BVAS v.3 and PGA, treatment decision, and ESR. RESULTS: A total of 152 patients were included. The physician diagnosis of these patients was predominantly granulomatosis with polyangiitis (n = 99). The median BVAS v.3 score was 18.0 (range 0-40). The BVAS v.3 correlations were r(s) = 0.379 (95% CI 0.233 to 0.509) with PGA, r(s) = 0.521 (95% CI 0.393 to 0.629) with treatment decision, and r(s) = 0.403 (95% CI 0.253 to 0.533) with ESR. CONCLUSION: Applied to children with AAV, BVAS v.3 had a weak correlation with PGA and moderate correlation with both ESR and treatment decision. Prospective evaluation of BVAS v.3 and/or pediatric-specific modifications to BVAS v.3 may be required before it can be formalized as a disease activity assessment tool in pediatric AAV.

Classification, presentation, and initial treatment of Wegener's granulomatosis in childhood.

OBJECTIVE: To compare the criteria for Wegener's granulomatosis (WG) of the American College of Rheumatology (ACR) with those of the European League Against Rheumatism/Pediatric Rheumatology European Society (EULAR/PRES) in a cohort of children with WG and other antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs), and to describe the interval to diagnosis, presenting features, and initial treatment for WG. METHODS: Eligible patients had been diagnosed by site rheumatologists (termed the "MD diagnosis") since 2004. This diagnosis was used as a reference standard for sensitivity and specificity testing of the 2 WG classification criteria. Descriptive analyses were confined to ACR-classified WG patients. RESULTS: MD diagnoses of 117 patients (82 of whom were female) were WG (n = 76), microscopic polyangiitis (n = 17), ANCA-positive pauci-immune glomerulonephritis (n = 5), Churg-Strauss syndrome (n = 2), and unclassified vasculitis (n = 17). The sensitivities of the ACR and EULAR/PRES classification criteria for WG among the spectrum of AAVs were 68.4% and 73.6%, respectively, and the specificities were 68.3% and 73.2%, respectively. Two more children were identified as having WG by the EULAR/PRES criteria than by the ACR criteria. For the 65 ACR-classified WG patients, the median age at diagnosis was 14.2 years (range 4-17 years), and the median interval from symptom onset to diagnosis was 2.7 months (range 0-49 months). The most frequent presenting features by organ system were constitutional (89.2%), pulmonary (80.0%), ear, nose, and throat (80.0%), and renal (75.4%). Fifty-four patients (83.1%) commenced treatment with the combination of corticosteroids and cyclophosphamide, with widely varying regimens; the remainder received methotrexate alone (n = 1), corticosteroids alone (n = 4), or a combination (n = 6). CONCLUSION: The EULAR/PRES criteria minimally improved diagnostic sensitivity and specificity for WG among a narrow spectrum of children with AAVs. Diagnostic delays may result from poor characterization of childhood WG. Initial therapy varied considerably among participating centers.