Faculty Bibliography

Type I interferon (IFN) is critical in our defense against viral infections. Increased type I IFN pathway activation is a genetic risk factor for systemic lupus erythematosus (SLE), and a number of common risk alleles contribute to the high IFN trait. We hypothesized that these common gain-of-function IFN pathway alleles may be associated with protection from mortality in acute COVID-19. We studied patients admitted with acute COVID-19 (756 European-American and 398 African-American ancestry). Ancestral backgrounds were analyzed separately, and mortality after acute COVID-19 was the primary outcome. In European-American ancestry, we found that a haplotype of interferon regulatory factor 5 (IRF5) and alleles of protein kinase cGMP-dependent 1 (PRKG1) were associated with mortality from COVID-19. Interestingly, these were much stronger risk factors in younger patients (OR=29.2 for PRKG1 in ages 45-54). Variants in the IRF7 and IRF8 genes were associated with mortality from COVID-19 in African-American subjects, and these genetic effects were more pronounced in older subjects. Combining genetic information with blood biomarker data such as C-reactive protein, troponin, and D-dimer resulted in significantly improved predictive capacity, and in both ancestral backgrounds the risk genotypes were most relevant in those with positive biomarkers (OR for death between 14 and 111 in high risk genetic/biomarker groups). This study confirms the critical role of the IFN pathway in defense against COVID-19 and viral infections, and supports the idea that some common SLE risk alleles exert protective effects in anti-viral immunity.

The search for effective COVID-19 management strategies continues to evolve. Current understanding of SARS-CoV-2 mechanisms suggests a central role for exaggerated activation of the innate immune system as an important contributor to COVID-19 adverse outcomes. The actions of colchicine, one of the oldest anti-inflammatory therapeutics, target multiple mechanisms associated with COVID-19 excessive inflammation. While many COVID-19 trials have sought to manipulate SARS-CoV-2 or dampen the inflammatory response once patients are hospitalised, few examine therapeutics to prevent the need for hospitalisation. Colchicine is easily administered, generally well tolerated and inexpensive, and holds particular promise to reduce the risk of hospitalisation and mortality due to COVID-19 in the outpatient setting. Successful outpatient treatment of COVID-19 could greatly reduce morbidity, mortality and the demand for rare or expensive care resources (front-line healthcare workers, hospital beds, ventilators, biological therapies), to the benefit of both resource-replete and resource-poor regions.

Macrophage activation syndrome (MAS) and hemophagocytic lymphohistiocytosis (HLH) are increasingly recognized as being on a continuum of cytokine storm syndromes, with different initiating pathways culminating in cytotoxic dysfunction and uncontrolled activation and proliferation of T lymphocytes and macrophages. The activated immune cells produce large amounts of proinflammatory cytokines, including interleukin 1β (IL)-1β. Management depends on the recognized diagnosis. In the setting of a cytokine storm syndrome and infection, collaborative involvement of specialists, including infectious disease and rheumatology is ideal. Anakinra, a recombinant IL-1 receptor antagonist, has been used subcutaneously and intravenously in pediatric patients and is considered a first-line treatment for MAS and secondary HLH (sHLH) among many pediatric rheumatologists. Previous reports of anakinra used in adults for treatment of MAS or sHLH are limited to subcutaneous administration. In this issue, Moneagudo et al. present a series of adult patients with sHLH treated with intravenous anakinra, including patients in whom subcutaneous anakinra was insufficient. As the authors suggest, there is a potential therapeutic use for anakinra in sHLH or the cytokine storm syndrome triggered by COVID19. Trial design will be key, with the patient subpopulation, timing of intervention, and doses tested important.

BACKGROUNDUndifferentiated systemic autoinflammatory diseases (USAIDs) present diagnostic and therapeutic challenges. Chronic interferon (IFN) signaling and cytokine dysregulation may identify diseases with available targeted treatments.METHODSSixty-six consecutively referred USAID patients underwent underwent screening for the presence of an interferon signature using a standardized type-I IFN-response-gene score (IRG-S), cytokine profiling, and genetic evaluation by next-generation sequencing.RESULTSThirty-six USAID patients (55%) had elevated IRG-S. Neutrophilic panniculitis (40% vs. 0%), basal ganglia calcifications (46% vs. 0%), interstitial lung disease (47% vs. 5%), and myositis (60% vs. 10%) were more prevalent in patients with elevated IRG-S. Moderate IRG-S elevation and highly elevated serum IL-18 distinguished 8 patients with pulmonary alveolar proteinosis (PAP) and recurrent macrophage activation syndrome (MAS). Among patients with panniculitis and progressive cytopenias, 2 patients were compound heterozygous for potentially novel LRBA mutations, 4 patients harbored potentially novel splice variants in IKBKG (which encodes NF-κB essential modulator [NEMO]), and 6 patients had de novo frameshift mutations in SAMD9L. Of additional 12 patients with elevated IRG-S and CANDLE-, SAVI- or Aicardi-Goutières syndrome-like (AGS-like) phenotypes, 5 patients carried mutations in either SAMHD1, TREX1, PSMB8, or PSMG2. Two patients had anti-MDA5 autoantibody-positive juvenile dermatomyositis, and 7 could not be classified. Patients with LRBA, IKBKG, and SAMD9L mutations showed a pattern of IRG elevation that suggests prominent NF-κB activation different from the canonical interferonopathies CANDLE, SAVI, and AGS.CONCLUSIONSIn patients with elevated IRG-S, we identified characteristic clinical features and 3 additional autoinflammatory diseases: IL-18-mediated PAP and recurrent MAS (IL-18PAP-MAS), NEMO deleted exon 5-autoinflammatory syndrome (NEMO-NDAS), and SAMD9L-associated autoinflammatory disease (SAMD9L-SAAD). The IRG-S expands the diagnostic armamentarium in evaluating USAIDs and points to different pathways regulating IRG expression.TRIAL REGISTRATIONClinicalTrials.gov NCT02974595.FUNDINGThe Intramural Research Program of the NIH, NIAID, NIAMS, and the Clinical Center.

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are two common autoimmune rheumatic diseases that vary in severity, clinical presentation, and disease course between individuals. Molecular and genetic studies of both diseases have identified candidate genes and molecular pathways that are linked to various disease outcomes and treatment responses. Currently, patients can be grouped into molecular subsets in each disease, and these molecular categories should enable precision medicine approaches to be applied in rheumatic diseases. In this article, we will review key lessons learned about disease heterogeneity and molecular characterization in rheumatology, which we hope will lead to personalized therapeutic strategies.

Previously, we demonstrated in test and validation cohorts that type I IFN (T1IFN) activity can predict non-response to tumor necrosis factor inhibitors (TNFi) in rheumatoid arthritis (RA). In this study, we examine the biology of non-classical and classical monocytes from RA patients defined by their pre-biologic treatment T1IFN activity. We compared single cell gene expression in purified classical (CL, n = 342) and non-classical (NC, n = 359) monocytes. In our previous work, RA patients who had either high IFNβ/α activity (>1.3) or undetectable T1IFN were likely to have EULAR non-response to TNFi. In this study comparisons were made among patients grouped according to their pre-biologic treatment T1IFN activity as clinically relevant: "T1IFN undetectable (T1IFN ND) or IFNβ/α >1.3" (n = 9) and "T1IFN detectable but IFNβ/α ≤ 1.3" (n = 6). In addition, comparisons were made among patients grouped according to their T1IFN activity itself: "T1IFN ND," "T1IFN detected and IFNβ/α ≤ 1.3," and "IFNβ/α >1.3." Major differences in gene expression were apparent in principal component and unsupervised cluster analyses. CL monocytes from the T1IFN ND or IFNβ/α >1.3 group were unlikely to express JAK1 and IFI27 (p < 0.0001 and p 0.0005, respectively). In NC monocytes from the same group, expression of IFNAR1, IRF1, TNFA, TLR4 (p ≤ 0.0001 for each) and others was enriched. Interestingly, JAK1 expression was absent in CL and NC monocytes from nine patients. This pattern most strongly associated with the IFNβ/α>1.3 group. Differences in gene expression in monocytes among the groups suggest differential IFN pathway activation in RA patients who are either likely to respond or to have no response to TNFi. Additional transcripts enriched in NC cells of those in the T1IFN ND and IFNβ/α >1.3 groups included MYD88, CD86, IRF1, and IL8. This work could suggest key pathways active in biologically defined groups of patients, and potential therapeutic strategies for those patients unlikely to respond to TNFi.

Objective/UNASSIGNED: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/UNASSIGNED: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. Spearman correlation and mixed models were used to examine whether cytokines at a previous visit predict change in disease activity at the next visit. Results/UNASSIGNED:< 0.001) disease activity scores. Preliminary results revealed significant correlations of previous IFNCK score and IL-6 with subsequent disease activity measures, but after adjustment for multiple visits per patient, these associations did not reach statistical significance. Conclusion/UNASSIGNED:There is a potential relationship between IFNCK and other cytokine scores seen in adult and juvenile DM with future disease states.

OBJECTIVE: We describe a 38-year-old woman presenting with a history of inflammatory arthritis, rash and daily fevers. She was noted to have chronic parvoviral infection with persistently detectable viral titers and a novel mutation in the ELANE gene. ELANE encodes neutrophil elastase, a neutrophil serine protease with important antimicrobial effects and is found as part of neutrophil extracellular trap (NET) complexes. Pathogenic ELANE mutations have been described in forms of hereditary neutropenia. However, our patient was never neutropenic. Because of the striking clinical scenario, we investigated this mutation functionally. METHODS: NET formation by neutrophils was assessed by scanning electron microscopy. Neutrophil activation and neutrophil elastase production were studied by flow cytometry and fluorescent substrate based functional assay, respectively. Multiplex assay was used to quantitate neutrophil inflammatory cytokine production. PYMOL software was used to generate three-dimensional models of mutant elastase. RESULTS: The patient's activated neutrophils demonstrated significantly decreased ability to form NETs by scanning electron microscopy, as well as quantitative defects in neutrophil activation and neutrophil elastase activity. The patient's neutrophils demonstrated altered levels of IL-12 and IL-8 - key cytokines for antiviral immunity and neutrophil chemotaxis. Three-dimensional mapping revealed that the mutation could alter protein folding and surface charge distribution, potentially perturbing protein trafficking. Thus, the mutation could impact neutrophil function by decreasing NETosis, and altering key antiviral activities of neutrophils. CONCLUSIONS: This is the first report of a human pathogenic ELANE mutation associated with a defect in NET-osis and a distinct syndrome of recurrent viral infection and chronic inflammation.

OBJECTIVE: Studies suggest that circulating type I interferon (IFN) may predict response to biological agents in rheumatoid arthritis (RA). Prediction of response prior to initiating therapy would represent a major advancement. METHODS: We studied sera from a test set of 32 patients with RA from the Auto-immune Biomarkers Collaborative Network Consortium and a validation set of 92 patients with RA from the Treatment Efficacy and Toxicity in Rheumatoid Arthritis Database and Repository registry. The test set included those with good response or no response to tumour necrosis factor (TNF) inhibitors at 14 weeks by European League Against Rheumatism criteria. The validation set included subjects with good, moderate or no response at 12 weeks. Total serum type I IFN activity, IFN-alpha and IFN-beta activity were measured using a functional reporter cell assay. RESULTS: In the test set, an increased ratio of IFN-beta to IFN-alpha (IFN-beta/alpha activity ratio) in pretreatment serum associated with lack of response to TNF inhibition (p=0.013). Anti-cyclic citrullinated peptide antibody titre and class of TNF inhibitor did not influence this relationship. A receiver-operator curve supported a ratio of 1.3 as the optimal cut-off. In the validation set, subjects with an IFN-beta/alpha activity ratio >1.3 were significantly more likely to have non-response than good response (OR=6.67, p=0.018). The test had 77% specificity and 45% sensitivity for prediction of non-response compared with moderate or good response. Meta-analysis of test and validation sets confirmed strong predictive capacity of IFN-beta/alpha activity ratio (p=0.005). CONCLUSIONS: Increased pretreatment serum IFN-beta/alpha ratio strongly associated with non-response to TNF inhibition. This study supports further investigation of serum type I IFN in predicting outcome of TNF inhibition in RA.