BACKGROUND: The impact of coronavirus disease 2019 on pregnant women is incompletely understood, but early data from case series suggest a variable course of illness from asymptomatic or mild disease to maternal death. It is unclear whether pregnant women manifest enhanced disease similar to influenza viral infection or whether specific risk factors might predispose to severe disease. OBJECTIVE: To describe maternal disease and obstetrical outcomes associated with coronavirus disease 2019 in pregnancy to rapidly inform clinical care. STUDY DESIGN: This is a retrospective study of pregnant patients with a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection from 6 hospital systems in Washington State between Jan. 21, 2020, and April 17, 2020. Demographics, medical and obstetrical history, and coronavirus disease 2019 encounter data were abstracted from medical records. RESULTS: A total of 46 pregnant patients with a severe acute respiratory syndrome coronavirus 2 infection were identified from hospital systems capturing 40% of births in Washington State. Nearly all pregnant individuals with a severe acute respiratory syndrome coronavirus 2 infection were symptomatic (93.5%, n¼43) and the majority were in their second or third trimester (43.5% [n¼20] and 50.0% [n¼23], respectively). Symptoms resolved in a median of 24 days (interquartile range, 13e37). Notably, 7 women were hospitalized (16%) including 1 admitted to the intensive care unit. A total of 6 cases (15%) were categorized as severe coronavirus disease 2019 with nearly all patients being either overweight or obese before pregnancy or with asthma or other comorbidities. Of the 8 deliveries that occurred during the study period, there was 1 preterm birth at 33 weeks' gestation to improve pulmonary status in a woman with class III obesity, and 1 stillbirth of unknown etiology. CONCLUSION: Severe coronavirus disease 2019 developed in approximately 15% of pregnant patients and occurred primarily in overweight or obese women with underlying conditions. Obesity and coronavirus disease 2019 may synergistically increase risk for a medically indicated preterm birth to improve maternal pulmonary status in late pregnancy. These findings support categorizing pregnant patients as a higher-risk group, particularly those with chronic comorbidities.

On behalf of the Washington State COVID-19 in Pregnancy Collaborative BACKGROUND: Evidence is accumulating that coronavirus disease 2019 increases the risk of hospitalization and mechanical ventilation in pregnant patients and for preterm delivery. However, the impact on maternal mortality and whether morbidity is differentially affected by disease severity at delivery and trimester of infection are unknown. OBJECTIVE: This study aimed to describe disease severity and outcomes of severe acute respiratory syndrome coronavirus 2 infections in pregnancy across the Washington State, including pregnancy complications and outcomes, hospitalization, and case fatality. STUDY DESIGN: Pregnant patients with a polymerase chain reactioneconfirmed severe acute respiratory syndrome coronavirus 2 infection between March 1, 2020, and June 30, 2020, were identified in a multicenter retrospective cohort study from 35 sites in Washington State. Sites captured 61% of annual state deliveries. Case-fatality rates in pregnancy were compared with coronavirus disease 2019 fatality rates in similarly aged adults in Washington State using rate ratios and rate differences. Maternal and neonatal outcomes were compared by trimester of infection and disease severity at the time of delivery. RESULTS: The principal study findings were as follows: (1) among 240 pregnant patients in Washington State with severe acute respiratory syndrome coronavirus 2 infections, 1 in 11 developed severe or critical disease, 1 in 10 were hospitalized for coronavirus disease 2019, and 1 in 80 died; (2) the coronavirus disease 2019eassociated hospitalization rate was 3.5-fold higher than in similarly aged adults in Washington State (10.0% vs 2.8%; rate ratio, 3.5; 95% confidence interval, 2.3e5.3);(3) pregnant patients hospitalized for a respiratory concern were more likely to have a comorbidity or underlying conditions including asthma, hypertension, type 2 diabetes mellitus, autoimmune disease, and class III obesity; (4) 3 maternal deaths (1.3%) were attributed to coronavirus disease 2019 for a maternal mortality rate of 1250 of 100,000 pregnancies (95% confidence interval, 257e3653); (5) the coronavirus disease 2019 case fatality in pregnancy was a significant 13.6-fold (95% confidence interval, 2.7e43.6) higher in pregnant patients than in similarly aged individuals in Washington State with an absolute difference in mortality rate of 1.2% (95% confidence interval, À0.3 to 2.6); and (6) preterm birth was significantly higher among women with severe or critical coronavirus disease 2019 at delivery than for women who had recovered from coronavirus disease 2019 (45.4% severe or critical coronavirus disease 2019 vs 5.2% mild coronavirus disease 2019; P<.001). CONCLUSION: Coronavirus disease 2019 hospitalization and casefatality rates in pregnant patients were significantly higher than in similarly aged adults in Washington State. These data indicate that pregnant patients are at risk of severe or critical disease and mortality compared to nonpregnant adults, and also...

BACKGROUND & AIMS An increased number of macrophages in adipose tissue is associated with insulin resistance and metabolic dysfunction in obese people. However, little is known about other immune cells in adipose tissue from obese people, and whether they contribute to insulin resistance. We investigated the characteristics of T cells in adipose tissue from metabolically abnormal insulin-resistant obese (MAO) subjects, metabolically normal insulin-sensitive obese (MNO) subjects, and lean subjects. Insulin sensitivity was determined by using the hyperinsulinemic euglycemic clamp procedure. METHODS We assessed plasma cytokine concentrations and subcutaneous adipose tissue CD4+ T-cell populations in 9 lean, 12 MNO, and 13 MAO subjects. Skeletal muscle and liver samples were collected from 19 additional obese patients undergoing bariatric surgery to determine the presence of selected cytokine receptors. RESULTS Adipose tissue from MAO subjects had 3- to 10-fold increases in numbers of CD4+ T cells that produce interleukin (IL)-22 and IL-17 (a T-helper [Th] 17 and Th22 phenotype) compared with MNO and lean subjects. MAO subjects also had increased plasma concentrations of IL-22 and IL-6. Receptors for IL-17 and IL-22 were expressed in human liver and skeletal muscle samples. IL-17 and IL-22 inhibited uptake of glucose in skeletal muscle isolated from rats and reduced insulin sensitivity in cultured human hepatocytes. CONCLUSIONS Adipose tissue from MAO individuals contains increased numbers of Th17 and Th22 cells, which produce cytokines that cause metabolic dysfunction in liver and muscle in vitro. Additional studies are needed to determine whether these alterations in adipose tissue T cells contribute to the pathogenesis of insulin resistance in obese people.

Noroviruses are important human pathogens responsible for most cases of viral epidemic gastroenteritis worldwide. Murine norovirus-1 (MNV-1) is one of several murine noroviruses isolated from research mouse facilities and has been used as a model of human norovirus infection. MNV-1 infection has been shown to require components of innate and adaptive immunity for clearance; however, the initial host protein that recognizes MNV-1 infection is unknown. Because noroviruses are RNA viruses, we investigated whether MDA5 and TLR3, cellular sensors that recognize dsRNA, are important for the host response to MNV-1. We demonstrate that MDA5−/− dendritic cells(DC) have a defect in cytokine response to MNV-1. In addition, MNV-1 replicates to higher levels in MDA5−/− DCs as well as in MDA5−/− mice in vivo. Interestingly, TLR3−/− DCs do not have a defect in vitro, but TLR3−/− mice have a slight increase in viral titers. This is the first demonstration of an innate immune sensor for norovirus and shows that MDA5 is required for the control of MNV-1 infection. Knowledge of the host response to MNV-1 may provide keys for prevention and treatment of the human disease.

The double-stranded RNA (dsRNA) analogue poly(I:C) is a promising adjuvant for cancer vaccines because it activates both dendritic cells (DCs) and natural killer (NK) cells, concurrently promoting adaptive and innate anticancer responses. Poly(I:C) acts through two dsRNA sensors, Toll-like receptor 3 (TLR3) and melanoma differentiation-associated protein-5 (MDA5). Here, we investigated the relative contributions of MDA5 and TLR3 to poly(I:C)-mediated NK cell activation using MDA5−/−, TLR3−/−, and MDA5−/−TLR3−/− mice. MDA5 was crucial for NK cell activation, whereas TLR3 had a minor impact most evident in the absence of MDA5. MDA5 and TLR3 activated NK cells indirectly through accessory cells and induced the distinct stimulatory cytokines interferon-α and interleukin-12, respectively. To identify the relevant accessory cells in vivo, we generated bone marrow chimeras between either wild-type (WT) and MDA5−/− or WT and TLR3−/− mice. Interestingly, multiple accessory cells were implicated, with MDA5 acting primarily in stromal cells and TLR3 predominantly in hematopoietic cells. Furthermore, poly(I:C)-mediated NK cell activation was not notably impaired in mice lacking CD8α DCs, providing further evidence that poly(I:C) acts through diverse accessory cells rather than solely through DCs. These results demonstrate distinct yet complementary roles for MDA5 and TLR3 in poly(I:C)-mediated NK cell activation.

Neutrophils, historically known for their involvement in acute inflammation, are also targets for infection by many different DNA and RNA viruses. However, the mechanisms by which they recognize and respond to viral components are poorly understood. Polyinosinic:polycytidylic acid (poly(I:C)) is a synthetic mimetic of viral dsRNA that is known to interact either with endosomal TLR3 (not expressed by human neutrophils) or with cytoplasmic RNA helicases such as melanoma differentiation-associated gene 5 (MDA5) and retinoic acid-inducible gene I (RIG-I). In this study, we report that intracellularly administered poly(I:C) stimulates human neutrophils to specifically express elevated mRNA levels encoding type I IFNs, immunoregulatory cytokines, and chemokines, such as TNF-α, IL-12p40, CXCL10, CXCL8, CCL4, and CCL20, as well as classical IFN-responsive genes (IRG), including IFIT1 (IFN-induced protein with tetratricopeptide repeats 1)/IFN-stimulated gene (ISG)56, G1P2/ISG15, PKR (dsRNA-dependent protein kinase), and IFN-regulatory factor (IRF)7. Investigations into the mechanisms whereby transfected poly(I:C) promotes gene expression in neutrophils uncovered a crucial involvement of the MAPK-, PKR-, NF-κB-, and TANK (TNF receptor-associated NF-κB kinase)-binding kinase (TBK1)/IRF3-signaling transduction pathways, as illustrated by the use of specific pharmacological inhibitors. Consistent with the requirement of the cytoplasmic dsRNA pathway for antiviral signaling, human neutrophils were found to constitutively express significant levels of both MDA5 and RIG-I, but not TLR3. Accordingly, neutrophils isolated from MDA5-deficient mice had a partial impairment in the production of IFN-β and TNF-α upon infection with encephalomyocarditis virus. Taken together, our data demonstrate that neutrophils are able to activate antiviral responses via helicase recognition, thus acting at the frontline of immunity against viruses.

IntroductionInnate responses to viruses depend on pathogen recognition sensors that detect viral products and trigger the secretion of type I interferons (IFN-I), i.e., . Two types of sensors detect double-stranded (ds) RNA generated during infection with RNA viruses: endosomal TLR-3 and cytoplasmic retinoic acidinducible gene-I-like (RIG-I-like) receptors (RLR). TLR3 senses the dsRNAs that reach the endosomal compartment after phagocytosis of virally infected cells or apoptotic debris. RLRs include 2 IFNinducible helicases, melanoma differentiation-associated gene 5 (MDA5) and RIG-I, which detect dsRNA intermediates that are generated in the cytoplasm during viral replication. MDA5 specializes in the detection of picornaviruses, whereas RIG-I senses many other RNA viruses (5). These viral specificities depend on the ability of MDA5 and RIG-I to recognize dsRNA molecules of different lengths, structures, and 5′ caps (6-9).TLR3 transmits its intracellular signal through the adaptor protein Toll/IL-1 receptor domain-containing adaptor-inducing IFN-β (TRIF), which activates the transcription factor IFN regulatory factor-3 (IRF-3) and induces IFN-β production (1-4). RIG-I and MDA5 signal through another adaptor, IFN-β promoter stimulator-1 (IPS-1), which activates IRF-3 and IRF-7, inducing both IFN-β and IFN-α production. A third RLR, laboratory of genetics and physiology-2 (LGP2), detects dsRNA but lacks signaling domains and is thought to regulate MDA5 and RIG-I (10-12). IFN-I induces an antiviral state in uninfected cells and promote apoptosis of infected cells, limiting viral spread (13). Moreover, IFN-I has independent immunomodulatory effects and helps to orchestrate NK, T, and B cell responses, which facilitate viral clearance (13-15).Type I diabetes (T1D) is an autoimmune disease that is primarily caused by selective destruction of islet β cells of the endocrine pancreas by autoreactive T cells (16,17). Predisposing genetic factors, particularly MHC class II polymorphisms, play a predominant role in the pathogenesis of T1D. However, and experimental (23-25) studies have suggested that viral infections also may contribute to T1D, particularly infections by members of the enterovirus family of RNA viruses. These viruses may induce T1D by directly causing β cell damage and subsequent release of autoantigens that trigger autoreactive T cells (26)(27)(28)(29). Paradoxically, the host IFN-I response can have detrimental effects when it activates preexisting autoreactive T cells that escaped thymic selection (30-33). Accordingly, a synthetic analog of viral dsRNA, poly(I:C), precipitates diabetes in mouse and rat models, acting in part through . Consistent with this, genetic studies have recently shown that resistance to T1D is associated with polymorphisms in MDA5 that diminish the IFN-I response to dsRNA (41-44). Collectively, these studies pose a conundrum: by eliciting IFN-I response, dsRNA sensors may limit the cytopathic effect of β cell-tropic viruses, but they can also precipitate T1D by promoting IFN-I-ind...

Background During the early months of the coronavirus disease of 2019 (COVID-19) pandemic, risks to pregnant women of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were uncertain. Pregnant patients can serve as a model for the success of the clinical and public health response during public health emergencies as they are typically in frequent contact with the medical system. Population-based estimates of SARS-CoV-2 infections in pregnancy are unknown due to incomplete ascertainment of pregnancy status or inclusion of only single centers or hospitalized cases. Whether pregnant women were protected by the public health response or through their interactions with obstetrical providers in the early pandemic is poorly understood. Objective(s) To estimate the SARS-CoV-2 infection rate in pregnancy and examine disparities by race/ethnicity and English-language proficiency in Washington State. Study Design Pregnant patients with a polymerase chain reaction (PCR)-confirmed severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection diagnosed between March 1-June 30, 2020 were identified within 35 hospitals/clinic systems capturing 61% of annual deliveries in Washington State. Infection rates in pregnancy were estimated overall and by Washington State Accountable Community of Health (ACH) region and cross-sectionally compared to SARS-CoV-2 infection rates in similarly aged adults in Washington State. Race/ethnicity and language used for medical care among the pregnant patients were compared to recent data from Washington State. Results A total of 240 pregnant patients with SARS-CoV-2 infections were identified during the study period with 70.7% from minority racial and ethnic groups. The principal findings in our study are: 1) The SARS-CoV-2 infection rate in pregnancy was 13.9/1,000 deliveries (95% confidence interval [CI], 8.3-23.2) compared to 7.3/1,000 (95%CI 7.2-7.4) in 20-39 year old adults in Washington State (Rate Ratio [RR] 1.7, 95%CI 1.3-2.3), 2) the SARS-CoV-2 infection rate reduced to 11.3/1000 (95%CI 6.3-20.3) when excluding 45 cases of SARS-CoV-2 detected through asymptomatic screening (RR 1.3, 95%CI 0.96-1.9), 3) the proportion of SARS-CoV-2 cases in pregnancy among most non-white racial/ethnic groups was 2-4 fold higher than the race and ethnicity distribution of women in Washington State who delivered live births in 2018, and 5) the proportion of SARS-CoV-2 infected pregnant patients receiving medical care in a non-English language was higher than estimates of limited English proficiency in Washington State (30.4% versus 7.6%). Conclusions The SARS-CoV-2 infection rate in pregnant people was 70% higher than similarly aged adults in Washington State, which could not be completely explained by universal screening at delivery. Pregnant patients from nearly all racial/ethnic minority groups and patients receiving medical care in a non-English...