Hospitalization and Mortality Due to Infection Among Children and Adolescents With Systemic Lupus Erythematosus in the United States.

OBJECTIVE: We aimed to determine the frequency and types of infections in hospitalized children with childhood-onset systemic lupus erythematosus (cSLE), and to identify risk factors for intensive care unit (ICU) admission and mortality. METHODS: We conducted a retrospective study of youth aged 2 to 21 years using International Classification of Diseases (ICD) codes for SLE assigned during admission to a hospital participating in the Pediatric Health Information System, a database of United States children's hospitals, from 2009 to 2021. Generalized linear mixed effects models were used to identify risk factors for ICU admission and mortality among children hospitalized with infection. RESULTS: We identified 8588 children with cSLE and ≥ 1 hospitalization. Among this cohort, there were 26,269 hospitalizations, of which 13% had codes for infections, a proportion that increased over time (P = 0.04). Bacterial pneumonia was the most common hospitalized infection. In-hospital mortality occurred in 0.4% (n = 103) of cSLE hospitalizations for any indication and 2% of hospitalizations for infection (n = 60). The highest mortality rates occurred with Pneumocystis jirovecii pneumonia (21%) and other fungal infections (21%). Lupus nephritis (LN) and endstage renal disease (ESRD) were associated with increased odds of ICU admission (odds ratio [OR] 1.47 [95% CI 1.2-1.8] and OR 2.40 [95% CI 1.7-3.4]) among children admitted for serious infection. ESRD was associated with higher mortality (OR 2.34 [95% CI 1.1-4.9]). CONCLUSION: Hospitalizations with ICD codes for infection comprised a small proportion of cSLE admissions but accounted for the majority of mortality. The proportion of hospitalizations for infection increased over time. LN and ESRD were risk factors for poor outcomes.

Insurance Status and Tumor Necrosis Factor Inhibitor Initiation Among Children With Juvenile Idiopathic Arthritis in the CARRA Registry.

OBJECTIVE: Prompt escalation to tumor necrosis factor inhibitors (TNFis) is recommended for children with juvenile idiopathic arthritis (JIA) and ongoing disease activity despite treatment with conventional disease-modifying antirheumatic drugs (cDMARDs). It is unknown whether these recommendations are equitably followed for children with different insurance types. We assessed the association of insurance coverage on the odds and timing of TNFi use. METHODS: We conducted a retrospective study of children with newly diagnosed JIA in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry. We compared the odds of starting a TNFi in the first year and time from cDMARD to TNFi initiation between those with public and private insurance. RESULTS: We identified 1086 children with new JIA diagnoses. Publicly insured children had significantly higher active joint counts and parent/patient global assessment scores at the enrollment visit. They were also more likely to have polyarticular arthritis compared to those with private insurance. Odds of any TNFi use in the first year did not differ between publicly and privately insured children. Publicly insured children were escalated from cDMARD to TNFi more quickly than privately insured children. CONCLUSION: Children who were publicly insured had more severe disease and polyarticular involvement at registry enrollment compared to those who were privately insured. Whereas overall TNFi use did not differ between children with different insurance types, publicly insured children were escalated more quickly, consistent with their increased disease severity. Further research is needed to determine why insurance coverage type is associated with disease severity, including how other socioeconomic factors affect presentation to care.

Real-world use and outcomes of belimumab in childhood-onset lupus: A single-center retrospective study.

BACKGROUND: Studies of real-world effectiveness of belimumab in adults with systemic lupus erythematosus have shown improved disease control and decreased oral glucocorticoid use. However, belimumab use outside of clinical trial settings has not been well studied in childhood-onset systemic lupus erythematosus (cSLE). We aimed to characterize indications for belimumab use and evaluate oral glucocorticoid doses and disease activity scores in the year following belimumab initiation at a single, large pediatric rheumatology center. METHODS: We included children and young adults with cSLE who received ≥ 1 dose of belimumab. Repeated measures one-way ANOVA was used to compare SLEDAI-2K scores and prednisone-equivalent daily oral glucocorticoid doses at baseline, 6 months, and 12 months after belimumab initiation for those who continued therapy for a year. RESULTS: We identified 21 patients with cSLE who received ≥ 1 dose of belimumab. The median disease duration at belimumab initiation was 30.8 months [IQR 21.0-79.1]. At the time of belimumab initiation, 100% of patients were taking an antimalarial, 81% were on oral glucocorticoids, and 91% were on at least one conventional DMARD. Thirteen patients (62%) continued belimumab for ≥6 months and 11 (52%) for ≥12 months. Among those continuing belimumab for ≥12 months, median [IQR] oral prednisone daily doses in milligrams at baseline, 6 months, and 12 months were 12.5 [7.5-17.5], 9 [6.25-10], and 5 [5-9.5], p = 0.037, and median [IQR] SLEDAI-2K scores at baseline, 6 months, and 12 months were 8 [5.5-10.5], 6 [3.5-10], and 6 [6-8.5], p = 0.548, respectively. CONCLUSIONS: In our cohort of pediatric patients with lupus and moderate disease activity treated with belimumab for ≥12 months, daily oral glucocorticoid doses were significantly lower 6 and 12 months after belimumab initiation than baseline. Use in patients with active nephritis was uncommon. Further research is needed in a large, multicenter cohort to determine the real-world effectiveness of belimumab in children and develop guidelines for use.

Clinical features of multisystem inflammatory syndrome in children.

PURPOSE OF REVIEW: To review diagnosis, clinical characteristics and treatment of multisystem inflammatory syndrome in children (MIS-C) associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RECENT FINDINGS: MIS-C emerged in spring 2020 as a hyperinflammatory syndrome following SARS-CoV-2 exposure in children. Despite growing awareness of MIS-C, diagnosis remains challenging due to the range of phenotypes and severity. Fever accompanied by shock, cardiac dysfunction, gastrointestinal symptoms, or mucocutaneous signs suggestive of Kawasaki disease, especially in the presence of known or suspected coronavirus disease 2019 exposure, should trigger consideration of MIS-C. However, clinical presentations are highly varied and may overlap with other infectious diseases. Clinicians must maintain a high index of suspicion for MIS-C and be aware that patients may develop coronary artery aneurysms and myocarditis even with few or no Kawasaki disease symptoms. More precise diagnostic criteria and specific biomarkers are needed to aid diagnosis. Intravenous immunoglobulin (IVIG) is first-line therapy, and steroids should be considered as initial adjunctive treatment for patients with severe manifestations or other risk factors. Prompt treatment is essential, as patients may worsen acutely, though overall prognosis is reassuring. SUMMARY: MIS-C associated with SARS-CoV-2 has varied clinical manifestations. Clinicians must be aware of the common presentation and potential for decompensation and cardiac sequalae to guide appropriate evaluation and treatment.

Hospitalised infections and rituximab administration among children and adolescents with systemic lupus erythematosus from 2009 to 2021.

BACKGROUND: Rituximab is associated with high infection rates, but studies of infections following rituximab in youth with childhood-onset SLE (cSLE) are limited. We conducted a retrospective longitudinal cohort study to assess the incidence of hospitalised infections following rituximab among children with cSLE and to assess changes in hospital-based rituximab administration over time. METHODS: Youth ages 2-21 years with an International Classification of Diseases (ICD) code for SLE who received rituximab during admission to a Pediatric Health Information System hospital from 2009 to 2021 were included. Incidence rates for infections requiring hospitalisation over the 12 months following first rituximab administration were calculated. Rituximab use by year of hospital discharge was tabulated. RESULTS: We identified 1567 children with cSLE who received rituximab. 219 children were admitted with an infection within 1 year after first rituximab administration, for an incidence rate of 140 cases per 1000 patient-years. Seven children (0.44%) died during a hospitalisation with an infection in the year following rituximab administration. The most common hospitalised infections were bacterial pneumonia, sepsis and cellulitis. 12 children were hospitalised with COVID-19, none of whom died. Hospitalisations with rituximab administered decreased from 2019 to 2021. CONCLUSIONS: In this cohort of patients with cSLE who received inpatient treatment with rituximab, we observed a 14% rate of hospitalisation with infection in the year following rituximab administration among youth with cSLE. Rituximab use declined during the COVID-19 pandemic. No fatalities with COVID-19 were observed. Given the lack of outpatient data, including doses of concomitant medications and disease activity measures, further research is needed to identify risk factors for infection following rituximab among children with cSLE.

Incidence and Risk Factors for Eosinophilia and Lung Disease in Biologic-Exposed Children With Systemic Juvenile Idiopathic Arthritis.

OBJECTIVE: Although interleukin-1 (IL-1)/IL-6 inhibitors are effective therapies for systemic juvenile idiopathic arthritis (JIA), some patients develop eosinophilia and lung disease during treatment. This study was undertaken to retrospectively evaluate incidence and risk factors for eosinophilia and describe lung disease outcomes in IL-1/IL-6 inhibitor-exposed patients with systemic JIA. METHODS: Among JIA patients at our institution exposed to interleukin-1 (IL-1)/IL-6 inhibitors (1995-2022), we compared incidence rate of eosinophilia in systemic JIA compared to other JIA, stratified by medication class (IL-1/IL-6 inhibitors, other cytokine inhibitors, methotrexate). We used Cox models to identify predictors of eosinophilia during IL-1/IL-6 inhibitor use and summarized treatment changes and outcomes after eosinophilia, including lung disease. HLA typing was performed on a clinical or research basis. RESULTS: There were 264 new medication exposures in 75 patients with systemic JIA and 41 patients with other JIA. A total of 49% of patients with systemic JIA with HLA typing (n = 45) were positive for HLA-DRB1*15 alleles. Eosinophilia was common during IL-1/IL-6 inhibitor use and did not differ by systemic JIA compared to other JIA (0.08 and 0.07 per person-year, respectively; P = 0.30). Among systemic JIA patients, pretreatment macrophage activation syndrome (MAS) was associated with a higher rate of subsequent eosinophilia on biologic therapy (unadjusted hazard ratio 3.2 [95% confidence interval 1.2-8.3]). A total of 4 of 5 patients who switched therapy within 10 weeks of eosinophilia experienced disease flare compared to none of the patients who continued the original therapy. A total of 8 of 25 patients with pulmonary evaluations had lung disease, and all had severe manifestations of systemic JIA (MAS, intensive care unit stay). One death was attributed to systemic JIA-lung disease. CONCLUSION: Eosinophilia is common in JIA patients using IL-1/IL-6 inhibitors. Severe disease may be associated with eosinophilia and lung disease in systemic JIA.

Association of Race and Ethnicity With Medication Use for Pediatric Lupus in the Childhood Arthritis and Rheumatology Research Alliance Registry.

OBJECTIVE: Black and Hispanic children with pediatric lupus (pSLE) have higher morbidity and mortality than non-Hispanic White children. The extent to which differences in outcomes are due to treatment disparities, including medication use, is unknown. We aimed to determine whether medication use in pSLE is associated with race and ethnicity in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry. METHODS: Patients with pSLE enrolled in the CARRA Registry from 2017 to 2020 were included. Multivariable mixed-effect logistic regression, adjusted for site of care, was used to compare use of antimalarials, high-dose oral glucocorticoids, and rituximab in Black and Hispanic children. RESULTS: We identified 639 children with pSLE, of whom 480 had at least 1 year of follow-up. At enrollment, 89% of patients were prescribed an antimalarial and 50% were on high-dose glucocorticoids. Of those with 1 year of follow-up, 12% received rituximab. Nephritis, shorter disease duration, and higher Systemic Lupus Erythematosus Disease Activity Index 2000 scores were associated with high-dose glucocorticoid use. Antimalarial use was higher among those with nephritis and lower in children with no insurance. Rituximab use was associated with Black race in the fixed-effects model but not when adjusted for site of care. CONCLUSION: We identified differences in medication use by race and insurance status. Site of care was associated with the racial differences observed in rituximab use. Further research is needed to optimize pSLE treatments particularly where use is highly variable, including glucocorticoid dosing and use of rituximab, and understand the impact of practice variation on disparities in pSLE outcomes.

Longitudinal assessment of preparation for care transition among adolescents and young adults with rheumatologic disease: a single-center pilot study.

Adolescents and young adults (AYA) with rheumatologic diseases are at high risk for poor outcomes and gaps in care when transitioning from pediatric to adult care. However, tools for evaluating transition readiness and assessing the impact of transition interventions are limited. We implemented a written transition policy at our pediatric rheumatology center and evaluated preparation for transition among AYA 16 and older before and after distribution. 31 of 77 patients completed the follow-up survey (response rate 40%). Patient report of transition counseling increased following written transition policy implementation, though these results were not statistically significant in our small cohort. Most follow-up respondents (n = 19, 61%) had not yet completed care transfer; 4 (13%) had arranged a visit with an adult rheumatologist and 8 (26%) had fully transitioned to adult care. Those who successfully completed care transfer were older, had completed higher levels of education, and had significantly higher baseline transition preparation scores compared to those with no transfer arranged or planned visit only. Our single-center pilot study demonstrated that longitudinal assessment of transition preparation is feasible and that scores are significantly associated with care transfer outcomes. Tracking transition preparation over time may provide practices with information on areas of highest need for transition guidance and predict successful transfer among AYA with rheumatologic disease.

Differentiating multisystem inflammatory syndrome in children: a single-centre retrospective cohort study.

OBJECTIVE: Features of multisystem inflammatory syndrome in children (MIS-C) overlap with other febrile illnesses, hindering prompt and accurate diagnosis. The objectives of this study were to identify clinical and laboratory findings that distinguished MIS-C from febrile illnesses in which MIS-C was considered but ultimately excluded, and to examine the diseases that most often mimicked MIS-C in a tertiary medical centre. STUDY DESIGN: We identified all children hospitalised with fever who were evaluated for MIS-C at our centre and compared clinical signs and symptoms, SARS-CoV-2 status and laboratory studies between those with and without MIS-C. Multivariable logistic LASSO (least absolute shrinkage and selection operator) regression was used to identify the most discriminative presenting features of MIS-C. RESULTS: We identified 50 confirmed MIS-C cases (MIS-C+) and 68 children evaluated for, but ultimately not diagnosed with, MIS-C (MIS-C-). In univariable analysis, conjunctivitis, abdominal pain, fatigue, hypoxaemia, tachypnoea and hypotension at presentation were significantly more common among MIS-C+ patients. MIS-C+ and MIS-C- patients had similar elevations in C-reactive protein (CRP), but were differentiated by thrombocytopenia, lymphopenia, and elevated ferritin, neutrophil/lymphocyte ratio, BNP and troponin. In multivariable analysis, predictors of MIS-C included age, neutrophil/lymphocyte ratio, platelets, conjunctivitis, oral mucosa changes, abdominal pain and hypotension. CONCLUSIONS: Among hospitalised children undergoing evaluation for MIS-C, children with MIS-C were older, more likely to present with conjunctivitis, oral mucosa changes, abdominal pain and hypotension, and had higher neutrophil/lymphocyte ratios and lower platelet counts. These data may be helpful for discrimination of MIS-C from other febrile illnesses, including bacterial lymphadenitis and acute viral infection, with overlapping features.

Pediatric to Adult Transition Literature: Scoping Review and Rheumatology Research Prioritization Survey Results.

The transition from pediatric to adult care is the focus of growing research. It is important to identify how to direct future research efforts for maximum effect. Our goals were to perform a scoping review of the transition literature, highlight gaps in transition research, and offer stakeholder guidance on the importance and feasibility of research questions designed to fill identified gaps. The transition literature on rheumatic diseases and other common pediatric-onset chronic diseases was grouped and summarized. Based on the findings, a survey was developed and disseminated to pediatric rheumatologists and young adults with rheumatic diseases as well as their caregivers. The transitional care needs of patients, healthcare teams, and caregivers is well described in the literature. While various transition readiness scales exist, no longitudinal posttransfer study confirms their predictive validity. Multiple outcome measures are used alone or in combination to define a successful transition or intervention. Multimodal interventions are most effective at improving transition-related outcomes. How broader health policy affects transition is poorly studied. Research questions that ranked highest for importance and feasibility included those related to identifying and tracking persons with psychosocial vulnerabilities or other risk factors for poor outcomes. Interventions surrounding improving self-efficacy and health literacy were also ranked highly. In contrast to healthcare teams (n = 107), young adults/caregivers (n = 23) prioritized research surrounding improved work, school, or social function. The relevant transition literature is summarized and future research questions prioritized, including the creation of processes to identify and support young adults vulnerable to poor outcomes.

Disordered T cell-B cell interactions in autoantibody-positive inflammatory arthritis.

T peripheral helper (Tph) cells, identified in the synovium of adults with seropositive rheumatoid arthritis, drive B cell maturation and antibody production in non-lymphoid tissues. We sought to determine if similarly dysregulated T cell-B cell interactions underlie another form of inflammatory arthritis, juvenile oligoarthritis (oligo JIA). Clonally expanded Tph cells able to promote B cell antibody production preferentially accumulated in the synovial fluid (SF) of oligo JIA patients with antinuclear antibodies (ANA) compared to autoantibody-negative patients. Single-cell transcriptomics enabled further definition of the Tph gene signature in inflamed tissues and showed that Tph cells from ANA-positive patients upregulated genes associated with B cell help to a greater extent than patients without autoantibodies. T cells that co-expressed regulatory T and B cell-help factors were identified. The phenotype of these Tph-like Treg cells suggests an ability to restrain T cell-B cell interactions in tissues. Our findings support the central role of disordered T cell-help to B cells in autoantibody-positive arthritides.

An Evidence-Based Guideline Improves Outcomes for Patients With Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome.

OBJECTIVE: To compare clinical outcomes in children with hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) who were managed before and after implementation of an evidence-based guideline (EBG). METHODS: A management algorithm for MAS-HLH was developed at our institution based on literature review, expert opinion, and consensus building across multiple pediatric subspecialties. An electronic medical record search retrospectively identified hospitalized patients with MAS-HLH in the pre-EBG (October 15, 2015, to December 4, 2017) and post-EBG (January 1, 2018, to January 21, 2020) time periods. Predetermined outcome metrics were evaluated in the 2 cohorts. RESULTS: After the EBG launch, 57 children were identified by house staff as potential patients with MAS-HLH, and rheumatology was consulted for management. Ultimately, 17 patients were diagnosed with MAS-HLH by the treating team. Of these, 59% met HLH 2004 criteria, and 94% met 2016 classification criteria for MAS complicating systemic juvenile idiopathic arthritis. There was a statistically significant reduction in mortality from 50% before implementation of the EBG to 6% in the post-EBG cohort (P = 0.02). There was a significant improvement in time to 50% reduction in C-reactive protein level in the post-EBG vs pre-EBG cohorts (log-rank P < 0.01). There were trends toward faster time to MAS-HLH diagnosis, faster initiation of immunosuppressive therapy, shorter length of hospital stay, and more rapid normalization of MAS-HLH-related biomarkers in the patients post-EBG. CONCLUSION: While the observed improvements may be partially attributed to advances in treatment of MAS-HLH that have accumulated over time, this analysis also suggests that a multidisciplinary treatment pathway for MAS-HLH contributed meaningfully to favorable patient outcomes.

Assessing preparation for care transition among adolescents with rheumatologic disease: a single-center assessment with patient survey.

BACKGROUND: Despite the risk for poor outcomes and gaps in care in the transfer from pediatric to adult care, most pediatric rheumatology centers lack formal transition pathways. As a first step in designing a pathway, we evaluated preparation for transition in a single-center cohort of adolescents and young adults (AYA) with rheumatologic conditions using the ADolescent Assessment of Preparation for Transition (ADAPT) survey. FINDINGS: AYA most frequently endorsed receiving counseling on taking charge of their health and remembering to take medications. Less than half reported receiving specific counseling about transferring to an adult provider. AYA with lower education attainment compared with those who had attended some college or higher had lower scores in self-management (1.51 vs 2.52, p = 0.0002), prescription medication counseling (1.96 vs 2.41, p = 0.029), and transfer planning (0.27 vs 1.62, p < 0.001). AYA with a diagnosis of MCTD, Sjögren's or SLE had higher self-management scores than those with other diagnoses (2.6 vs 1.9; p = 0.048). Non-white youth indicated receiving more thorough medication counseling than white youth (2.71 vs 2.07, p = 0.027). When adjusting for age, educational attainment remained an independent predictor of transfer planning (p = 0.037). AYA with longer duration of seeing their physician had higher transition preparation scores (p = 0.021). CONCLUSION: Few AYA endorsed receiving comprehensive transition counseling, including discussion of transfer planning. Those who were younger and with lower levels of education had lower preparation scores. A long-term relationship with providers was associated with higher scores. Further research, including longitudinal assessment of transition preparation, is needed to evaluate effective processes to assist vulnerable populations.

Mistaken MIS-C: A Case Series of Bacterial Enteritis Mimicking MIS-C.

Multisystem inflammatory syndrome in children following severe acute respiratory syndrome coronavirus 2 infection is characterized by fever, elevated inflammatory markers, and multisystem organ involvement. Presentations are variable but often include gastrointestinal symptoms. We describe 5 children with fever and gastrointestinal symptoms initially concerning for multisystem inflammatory syndrome in children who were ultimately diagnosed with bacterial enteritis, highlighting the diagnostic challenges presented by the severe acute respiratory syndrome coronavirus 2 pandemic.

Non-SARS-CoV-2 Infections Among Patients Evaluated for MIS-C Associated With COVID-19.

Clinical features of Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 are nonspecific. In this retrospective cohort study of 39 patients evaluated for MIS-C, 11 had non-SARS-CoV-2 infections, 3 of whom were also diagnosed with MIS-C. Clinical features were similar in patients with MIS-C and patients with non-SARS-CoV-2 infections. Clinicians should consider non-SARS-CoV-2 infections in patients undergoing MIS-C evaluation.

Socioeconomic and Racial and/or Ethnic Disparities in Multisystem Inflammatory Syndrome.

OBJECTIVES: To characterize the socioeconomic and racial and/or ethnic disparities impacting the diagnosis and outcomes of multisystem inflammatory syndrome in children (MIS-C). METHODS: This multicenter retrospective case-control study was conducted at 3 academic centers from January 1 to September 1, 2020. Children with MIS-C were compared with 5 control groups: children with coronavirus disease 2019, children evaluated for MIS-C who did not meet case patient criteria, children hospitalized with febrile illness, children with Kawasaki disease, and children in Massachusetts based on US census data. Neighborhood socioeconomic status (SES) and social vulnerability index (SVI) were measured via a census-based scoring system. Multivariable logistic regression was used to examine associations between SES, SVI, race and ethnicity, and MIS-C diagnosis and clinical severity as outcomes. RESULTS: Among 43 patients with MIS-C, 19 (44%) were Hispanic, 11 (26%) were Black, and 12 (28%) were white; 22 (51%) were in the lowest quartile SES, and 23 (53%) were in the highest quartile SVI. SES and SVI were similar between patients with MIS-C and coronavirus disease 2019. In multivariable analysis, lowest SES quartile (odds ratio 2.2 [95% confidence interval 1.1-4.4]), highest SVI quartile (odds ratio 2.8 [95% confidence interval 1.5-5.1]), and racial and/or ethnic minority background were associated with MIS-C diagnosis. Neither SES, SVI, race, nor ethnicity were associated with disease severity. CONCLUSIONS: Lower SES or higher SVI, Hispanic ethnicity, and Black race independently increased risk for MIS-C. Additional studies are required to target interventions to improve health equity for children.

Th1 polarization defines the synovial fluid T cell compartment in oligoarticular juvenile idiopathic arthritis.

Oligoarticular juvenile idiopathic arthritis (oligo JIA) is the most common form of chronic inflammatory arthritis in children, yet the cause of this disease remains unknown. To understand immune responses in oligo JIA, we immunophenotyped synovial fluid T cells with flow cytometry, bulk RNA-Seq, single-cell RNA-Seq (scRNA-Seq), DNA methylation studies, and Treg suppression assays. In synovial fluid, CD4+, CD8+, and γδ T cells expressed Th1-related markers, whereas Th17 cells were not enriched. Th1 skewing was prominent in CD4+ T cells, including Tregs, and was associated with severe disease. Transcriptomic studies confirmed a Th1 signature in CD4+ T cells from synovial fluid. The regulatory gene expression signature was preserved in Tregs, even those exhibiting Th1 polarization. These Th1-like Tregs maintained Treg-specific methylation patterns and suppressive function, supporting the stability of this Treg population in the joint. Although synovial fluid CD4+ T cells displayed an overall Th1 phenotype, scRNA-Seq uncovered heterogeneous effector and regulatory subpopulations, including IFN-induced Tregs, peripheral helper T cells, and cytotoxic CD4+ T cells. In conclusion, oligo JIA is characterized by Th1 polarization that encompasses Tregs but does not compromise their regulatory identity. Targeting Th1-driven inflammation and augmenting Treg function may represent important therapeutic approaches in oligo JIA.

Distinct clinical and immunological features of SARS-CoV-2-induced multisystem inflammatory syndrome in children.

BACKGROUNDPediatric SARS-CoV-2 infection can be complicated by a dangerous hyperinflammatory condition termed multisystem inflammatory syndrome in children (MIS-C). The clinical and immunologic spectrum of MIS-C and its relationship to other inflammatory conditions of childhood have not been studied in detail.METHODSWe retrospectively studied confirmed cases of MIS-C at our institution from March to June 2020. The clinical characteristics, laboratory studies, and treatment response were collected. Data were compared with historic cohorts of Kawasaki disease (KD) and macrophage activation syndrome (MAS).RESULTSTwenty-eight patients fulfilled the case definition of MIS-C. Median age at presentation was 9 years (range: 1 month to 17 years); 50% of patients had preexisting conditions. All patients had laboratory confirmation of SARS-CoV-2 infection. Seventeen patients (61%) required intensive care, including 7 patients (25%) who required inotrope support. Seven patients (25%) met criteria for complete or incomplete KD, and coronary abnormalities were found in 6 cases. Lymphopenia, thrombocytopenia, and elevation in inflammatory markers, D-dimer, B-type natriuretic peptide, IL-6, and IL-10 levels were common but not ubiquitous. Cytopenias distinguished MIS-C from KD and the degree of hyperferritinemia and pattern of cytokine production differed between MIS-C and MAS. Immunomodulatory therapy given to patients with MIS-C included intravenous immune globulin (IVIG) (71%), corticosteroids (61%), and anakinra (18%). Clinical and laboratory improvement were observed in all cases, including 6 cases that did not require immunomodulatory therapy. No mortality was recorded in this cohort.CONCLUSIONMIS-C encompasses a broad phenotypic spectrum with clinical and laboratory features distinct from KD and MAS.FUNDINGThis work was supported by the National Institutes of Health, National Institute of Arthritis and Musculoskeletal and Skin Diseases; the National Institute of Allergy and Infectious Diseases; Rheumatology Research Foundation Investigator Awards and Medical Education Award; Boston Children's Hospital Faculty Career Development Awards; the McCance Family Foundation; and the Samara Jan Turkel Center.