While platelets are the cellular mediators of thrombosis, platelets are also immune cells. Platelets interact both directly and indirectly with immune cells, impacting their activation and differentiation, as well as all phases of the immune response. Megakaryocytes (Mks) are the cell source of circulating platelets, and until recently Mks were typically only considered as bone marrow (BM) resident cells. However, platelet producing Mks also reside in the lung, and lung Mks express greater levels of immune molecules compared to BM Mks. We therefore sought to define the immune functions of lung Mks. Using single cell RNA-Seq of BM and lung myeloid enriched cells, we found that lung Mks (MkL) had gene expression patterns that are similar to antigen presenting cells (APC). This was confirmed using imaging and conventional flow cytometry. The immune phenotype of Mks was plastic and driven by the tissue immune environment as evidenced by BM Mks having a MkL like phenotype under the influence of pathogen receptor challenge and lung associated immune molecules, such as IL-33. Our in vitro and in vivo assays demonstrated that MkL internalized and processed both antigenic proteins and bacterial pathogens. Furthermore, MkL induced CD4+ T cell activation in a MHC II dependent manner both in vitro and in vivo. These data indicated that Mks in the lung had key immune regulatory roles dictated in part by the tissue environment.
Daphne N. Pariser, Zachary T. Hilt, Sara K. Ture, Sara K. Blick-Nitko, Mark R. Looney, Simon J. Cleary, Estheany Roman-Pagan, Jerry Saunders II, Steve N. Georas, Janelle M. Veazey, Ferralita Madere, Laura Tesoro Santos, Allison M. Arne, Nguyen PT Huynh, Alison C. Livada, Selena M. Guerrero-Martin, Claire E. Lyons, Kelly A. Metcalf Pate, Kathleen E. McGrath, James Palis, Craig Morrell
A considerable fraction of B cells recognize SARS-CoV-2 with germline-encoded elements of their B cell receptor resulting in the production of neutralizing and non-neutralizing antibodies. We found that antibody sequences from different discovery cohorts shared biochemical properties and could be retrieved across validation cohorts confirming the stereotyped character of this naive response in COVID-19. While neutralizing antibody sequences were found independently of disease severity in line with serological data, individual non-neutralizing antibody sequences were associated with fatal clinical courses suggesting detrimental effects of these antibodies. We mined 200 immune repertoires of healthy individuals and 500 of patients with blood or solid cancers - all acquired prior to the pandemic - for SARS-CoV-2 antibody sequences. While the largely unmutated B cell rearrangements occurred in a substantial fraction of immune repertoires from young and healthy individuals, these sequences were less likely found in individuals over 60 years of age and in cancer. This reflects B cell repertoire restriction in aging and cancer and may to a certain extent explain the different clinical COVID-19 courses observed in these risk groups. Future studies will have to address if this stereotyped B cell response to SARS-CoV-2 emerging from unmutated antibody rearrangements will create long-lived memory.
Lisa Paschold, Donjete Simnica, Edith Willscher, Maria J.G.T. Vehreschild, Jochen Dutzmann, Daniel G. Sedding, Christoph Schultheiß, Mascha Binder
Psoriasis is a chronic inflammatory skin disease characterized by inflammatory cell infiltration, as well as hyperproliferation of keratinocytes in skin lesions, and is considered a metabolic syndrome. We found that the expression of galectin-7 is reduced in the skin lesions of patients with psoriasis. IL-17A and TNF-α, two cytokines intimately involved in the development of psoriatic lesions, suppressed galectin-7 expression in human primary keratinocytes (HEKn cells) and the immortalized human keratinocyte cell line HaCaT. A galectin-7 knockdown in these cells elevated the production of IL-6 and IL-8 and enhanced ERK signaling when the cells were stimulated with IL-17A. Galectin-7 attenuated IL-17A–induced production of inflammatory mediators by keratinocytes via the miR-146a–ERK pathway. Moreover, galectin-7–deficient mice showed enhanced epidermal hyperplasia and skin inflammation in response to intradermal IL-23 injection. We identified fluvastatin as an inducer of galectin-7 expression by connectivity map (cMAP) analysis, confirmed this effect in keratinocytes, and demonstrated that fluvastatin attenuated IL-6 and IL-8 production induced by IL-17A. Thus, we validate a role of galectin-7 in the pathogenesis of psoriasis, in both epidermal hyperplasia and keratinocyte-mediated inflammatory responses, and formulated a rationale for the use of statins in the treatment of psoriasis.
Hung-Lin Chen, Chia-Hui Lo, Chi-Chun Huang, Meng-Ping Lu, Po-Yuan Hu, Chang-Shan Chen, Di-Yen Chueh, Peilin Chen, Teng-Nan Lin, Yuan-Hsin Lo, Yu-Ping Hsiao, Daniel K. Hsu, Fu-Tong Liu
Human antibody responses to severe acute respiratory syndrome-associated coronavirus-2 (SARS-CoV-2) hold intense interest with research efforts directed at optimizing antibody-based interventions and monitoring immune status. By relating individual variations in antibody response to coronavirus disease 2019 (COVID-19) severity, beneficial antiviral immune responses may be identified in detail. In this issue of the JCI, Secchi and collaborators describe antibody response profiles in 509 COVID-19 patients from Italy during the 2020 pandemic. The research team found that multiple antibody types to multiple SARS-CoV-2 antigens developed over four weeks. Notably, IgG against the spike receptor binding domain (RBD) was predictive of survival and IgA against the viral spike protein (S protein) associated with rapid virologic clearance. These results may help guide selection of convalescent plasma, hyperimmune products, monoclonal antibodies, and vaccine strategies for COVID-19.
Jeffrey P. Henderson
A growing number of long non-coding RNAs (lncRNAs) have emerged as vital metabolic regulators. However, most human lncRNAs are non-conserved and highly tissue-specific, vastly limiting our ability to identify human lncRNA metabolic regulators (hLMRs). In this study, we establish a pipeline to identify putative hLMRs that are metabolically sensitive, disease-relevant, and population applicable. We first progressively processed multilevel human transcriptome data to select liver lncRNAs that exhibit highly dynamic expression in the general population, show differential expression in a nonalcoholic fatty liver disease (NAFLD) population, and response to dietary intervention in a small NAFLD cohort. We then experimentally demonstrated the responsiveness of selected hepatic lncRNAs to defined metabolic milieus in a liver-specific humanized mouse model. Furthermore, by extracting a concise list of protein-coding genes that are persistently correlated with lncRNAs in general and NAFLD populations, we predicted the specific function for each hLMR. Using gain- and loss-of-function approaches in humanized mice as well as ectopic expression in conventional mice, we validated the regulatory role of one non-conserved hLMR in cholesterol metabolism by coordinating with an RNA-binding protein, PTBP1, to modulate the transcription of cholesterol synthesis genes. Our work overcome the heterogeneity intrinsic to human data to enable the efficient identification and functional definition of disease-relevant human lncRNAs in metabolic homeostasis.
Xiangbo Ruan, Ping Li, Yonghe Ma, Chengfei Jiang, Yi Chen, Yu Shi, Nikhil Gupta, Fayaz Seifuddin, Mehdi Pirooznia, Yasuyuki Ohnishi, Nao Yoneda, Megumi Nishiwaki, Gabrijela Dumbovic, John L. Rinn, Yuichiro Higuchi, Kenji Kawai, Hiroshi Suemizu, Haiming Cao
Mutations in the core RNA splicing factor SF3B1 are prevalent in leukemias and uveal melanoma but hotspot SF3B1 mutations are also seen in epithelial malignancies such as breast cancer. Although hotspot mutations in SF3B1 alter hematopoietic differentiation, whether SF3B1 mutations contribute to epithelial cancer development and progression is unknown. Here, we identify that SF3B1 mutations in mammary epithelial and breast cancer cells induce a recurrent pattern of aberrant splicing leading to activation of AKT and NF-kB, enhanced cell migration, and accelerated tumorigenesis. Transcriptomic analysis of human cancer specimens, MMTV-cre Sf3b1K700E/WT mice, and isogenic mutant cell lines identified hundreds of aberrant 3’ splice sites (3’ss) induced by mutant SF3B1. Consistently between mouse and human tumors, mutant SF3B1 promoted aberrant splicing (dependent on aberrant branchpoints as well as pyrimidines downstream of the cryptic 3’ss) and consequent suppression of PPP2R5A and MAP3K7, critical negative regulators of AKT and NF-kB. Coordinate activation of NF-kB and AKT signaling was observed in the knock-in models, leading to accelerated cell migration and tumor development in combination with mutant PIK3CA but also hypersensitizing cells to AKT kinase inhibitors. These data identify hotspot mutations in SF3B1 as an important contributor to breast tumorigenesis and reveal unique vulnerabilities in cancers harboring them.
Bo Liu, Zhaoqi Liu, Sisi Chen, Michelle Ki, Caroline Erickson, Jorge S. Reis-Filho, Benjamin H. Durham, Qing Chang, Elisa de Stanchina, Yiwei Sun, Raul Rabadan, Omar Abdel-Wahab, Sarat Chandarlapaty
Obesity occurs when energy expenditure is outweighed by energy intake. Tuberal hypothalamic nuclei, including the arcuate nucleus (ARC), ventromedial nucleus (VMH), and dorsomedial nucleus (DMH), control for food intake and energy expenditure. Here we reported that, contrary to females, male mice lacking circadian nuclear receptors REV-ERB alpha and beta in the tuberal hypothalamus (HDKO) gained excessive weight on an obesogenic high fat diet due to both decreased energy expenditure and increased food intake during the light phase. Moreover, rebound food intake after fasting was markedly increased in HDKO mice. Integrative transcriptomic and cistromic analyses revealed that such disruption in feeding behavior was due to perturbed REV-ERB-dependent leptin signaling in the ARC. Indeed, in vivo leptin sensitivity was impaired in HDKO mice on an obesogenic diet in a diurnal manner. Thus, REV-ERBs play a crucial role in hypothalamic control of food intake and diurnal leptin sensitivity in diet-induced obesity.
Marine Adlanmerini, Hoang C. B. Nguyen, Brianna M. Krusen, Clare W. Teng, Caroline E. Geisler, Lindsey C. Peed, Bryce J. Carpenter, Matthew R. Hayes, Mitchell A. Lazar
Dysfunction of primary cilia is related to dyshomeostasis, leading to a wide range of disorders. The ventromedial hypothalamus (VMH) is known to regulate several homeostatic processes, but those modulated specifically by VMH-primary cilia are not yet known. In this study, we identify VMH-primary cilia as an important organelle that maintains energy and skeletal homeostasis by modulating the autonomic nervous system. We established loss-of-function models of primary cilia in the VMH by either targeting IFT88 (IFT88 KOSF-1) using steroidogenic factor 1-Cre (SF1-Cre) or injecting an adeno-associated virus Cre (AAV-Cre) directly into the VMH. Functional impairments of VMH-primary cilia were linked to decreased sympathetic activation and central leptin resistance, which led to marked obesity and bone density accrual. Obesity was caused by hyperphagia, decreased energy expenditure, and blunted brown fat function, as well as associated with insulin and leptin resistance. The effect of bone density accrual was independent from obesity, as it was caused by the decreased sympathetic tone resulting in increased osteoblastic and decreased osteoclastic activities in the IFT88 KOSF-1 and VMH-primary cilia knock-down mice. Overall, our current study identifies VMH-primary cilia as a critical hypothalamic organelle that maintains energy and skeletal homeostasis.
Ji Su Sun, Dong Joo Yang, Ann W. Kinyua, Seul Gi Yoon, Je Kyung Seong, Juwon Kim, Seok Jun Moon, Dong Min Shin, Yun-Hee Choi, Ki Woo Kim
Dr. Nancy Brown, Dean of the Yale School of Medicine, shares her perspective on the challenges facing women and minority faculty members and trainees in academic medicine and provides a reflection on how leaders in academic medicine can promote diversity, equity, and inclusion to enhance their success.
Nancy J. Brown
COVID-19 spans and wide range of symptoms, sometimes with profound immune system involvement. How immune cell subsets change during the disease course and with disease severity needs further study. While myeloid cells have been shown to initiate and maintain responses to pneumonia and lung inflammation, often playing a role in resolution, their involvement with COVID-19 remains unknown. In this issue of the JCI, Sánchez-Cerrillo and Pedro-Landete et al. investigated dendritic cells and monocytes from blood and bronchial secretions of patients with varying COVID-19 severity and with healthy controls. The authors conclude that circulating monocytes and DCs migrate from the blood into the inflamed lungs. While sampling differences in sex, collection timing, bacteria/fungal infection, and corticosteroid treatment limit interpretation, we believe that reprograming monocyte or macrophages by targeting immunometabolism, epigenetics, or the cytokine milieu holds promise in resolving lung-inflammation associated with COVID-19.
Franco R. D'Alessio, Nicola M. Heller
BACKGROUND. Transcriptome sequencing (RNA-seq) improves diagnostic rates in individuals with suspected Mendelian conditions to varying degrees, primarily by directing the prioritization of candidate DNA variants identified on exome or genome sequencing (ES/GS). Here we implemented an RNA-seq guided method to diagnose individuals across a wide range of ages and clinical phenotypes. METHODS. One hundred fifteen undiagnosed adult and pediatric patients with diverse phenotypes and 67 family members (182 total individuals) underwent RNA-seq from whole blood and fibroblasts at the Baylor College of Medicine (BCM) Undiagnosed Diseases Network (UDN) clinical site from 2014-2020. We implemented a workflow to detect outliers in gene expression and splicing for cases that remained undiagnosed despite standard genomic and transcriptomic analysis. RESULTS. The transcriptome-directed approach resulted in a diagnostic rate of 12% across the entire cohort, or 17% after excluding cases solved on ES/GS alone. Newly diagnosed conditions included Koolen-de Vries syndrome (KANSL1), Renpenning syndrome (PQBP1), TBCK-associated encephalopathy, NSD2- and CLTC-related intellectual disability, and others, all with negative conventional genomic testing, including ES and chromosomal microarray (CMA). Fibroblasts exhibited higher and more consistent expression of clinically relevant genes than whole blood. In solved cases with RNA-seq from both tissues, the causative defect was missed in blood in half the cases but none from fibroblasts. CONCLUSION. For our cohort of undiagnosed individuals with suspected Mendelian conditions, transcriptome-directed genomic analysis facilitated diagnoses, primarily through the identification of variants missed on ES and CMA.
David R. Murdock, Hongzheng Dai, Lindsay C. Burrage, Jill A. Rosenfeld, Shamika Ketkar, Michaela F. Müller, Vicente A. Yépez, Julien Gagneur, Pengfei Liu, Shan Chen, Mahim Jain, Gladys Zapata, Carlos A. Bacino, Hsiao-Tuan Chao, Paolo Moretti, William J. Craigen, Neil A. Hanchard, Brendan Lee
Protein tyrosine phosphatase non-receptor type 2 (PTPN2) recently emerged as a promising cancer immunotherapy target. We set to investigate the functional role of PTPN2 in the pathogenesis of human colorectal carcinoma (CRC) as its role in immune-silent solid tumors is poorly understood. We demonstrate that in human CRC, increased PTPN2 expression and activity correlated with disease progression and decreased immune responses in tumor tissues. Particularly, stage II and III tumors displayed enhanced PTPN2 protein expression in tumor-infiltrating T-cells and increased PTPN2 levels negatively correlated with PD1, CTLA4, STAT1 and granzyme A. In vivo, T-cell and dendritic cell-specific PTPN2 deletion reduced tumor burden in several CRC models by promoting CD44+ effector/memory T-cells, as well as CD8+ T-cell infiltration and cytotoxicity into the tumor. In direct relevance to CRC treatment, T-cell-specific PTPN2 deletion potentiated anti-PD-1 efficacy and induced anti-tumor memory formation upon tumor re-challenge in vivo. Our data suggest a role for PTPN2 in suppressing anti-tumor immunity and promoting tumor development in CRC patients. Our in vivo results uncover PTPN2 as a key player in controlling immunogenicity of CRC, with the strong potential to be exploited to promote cancer immunotherapy.
Egle Katkeviciute, Larissa Hering, Ana Montalban-Arques, Philipp Busenhart, Marlene Schwarzfischer, Roberto Manzini, Javier Conde, Kirstin Atrott, Silvia Lang, Gerhard Rogler, Elisabeth Naschberger, Vera S. Schellerer, Michael Stürzl, Andreas Rickenbacher, Matthias Turina, Achim Weber, Sebastian Leibl, Gabriel E. Leventhal, Mitchell Levesque, Onur Boyman, Michael Scharl, Marianne R. Spalinger
Four different endemic coronaviruses (eCoVs) are etiologic agents for the seasonal “common cold,” and these eCoVs share extensive sequence homology with human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Here, we show that individuals with as compared to without a relatively recent documented eCoV were tested at greater frequency for respiratory infections but had similar rate of SARS-CoV-2 acquisition. Importantly, the patients with a previously detected eCoV had less severe coronavirus disease-2019 (COVID-19) illness. Our observations suggest that pre-existing immune responses against endemic human coronaviruses can mitigate disease manifestations from SARS-CoV-2 infection.
Manish Sagar, Katherine Reifler, Michael Rossi, Nancy S. Miller, Pranay Sinha, Laura White, Joseph P. Mizgerd
BACKGROUND. Serological assays are of critical importance to investigate correlates of response and protection in COVID-19, to define previous exposure to SARS-CoV-2 in populations and to verify the development of an adaptive immune response in infected individuals. METHODS. We studied 509 confirmed COVID-19 patients from the San Raffaele Hospital of Milan and 480 pre-pandemic organ donor sera collected in 2010-2012. Using fluid-phase luciferase immune precipitation (LIPS) assays, we characterized IgG, IgM, IgA antibodies to the spike Receptor Binding Domain (RBD), S1+S2, nucleocapsid, and ORF6 to 10 of SARS-CoV-2, to the HCoV-OC43 and HCoV-HKU1 betacoronaviruses spike S2, and the H1N1Ca2009 flu virus hemagglutinin. Sequential samples at 1 and 3 months post-hospital discharge were also tested in 95 patients for SARS-CoV-2 RBD antibodies. RESULTS. Antibodies developed rapidly against multiple SARS-CoV-2 antigens in 95% of patients by 4 weeks post-symptoms onset and IgG to the RBD increased until the 3rd month of follow-up. We observed a major synchronous expansion of antibodies to the HCoV-OC43 and HCoV-HKU1 spike S2. A likely co-infection with influenza was neither linked to a more severe presentation of the disease nor to a worse outcome. Of the measured antibody responses positivity for IgG against the SARS-CoV-2 spike RBD was predictive of survival. CONCLUSIONS. The measurement of antibodies to selected epitopes of SARS-CoV-2 antigens can offer a more accurate assessment of the humoral response in patients and its impact on survival. The presence of partially cross-reactive antibodies with other betacoronoviruses is likely to impact on serological assay specificity and interpretation.
Massimiliano Secchi, Elena Bazzigaluppi, Cristina Brigatti, Ilaria Marzinotto, Cristina Tresoldi, Patrizia Rovere-Querini, Andrea Poli, Antonella Castagna, Gabriella Scarlatti, Alberto Zangrillo, Fabio Ciceri, Lorenzo Piemonti, Vito Lampasona
Dysfunction of immune and vascular systems has been implicated in aging and Alzheimer’s disease; however, their interrelatedness remains poorly understood. The complement pathway is a well-established regulator of innate immunity in the brain. Here, we report robust age-dependent increases in vascular inflammation, peripheral lymphocyte infiltration, and blood-brain barrier (BBB) permeability. These phenotypes were subdued by global inactivation and by endothelial-specific ablation of C3ar1. Using an in vitro model of the BBB, we identify intracellular Ca2+ as a downstream effector of C3a-C3aR signaling and a functional mediator of VE-cadherins junction and barrier integrity. Endothelial C3ar1 inactivation also dampened microglia reactivity and improved hippocampal and cortical volumes in the aging brain, demonstrating a crosstalk between brain vasculature dysfunction and immune cell activation and neurodegeneration. Further, prominent C3aR-dependent vascular inflammation is also observed in a tau transgenic mouse model. Our studies suggest that heightened C3a-C3aR signaling through endothelial cells promotes vascular inflammation and BBB dysfunction and contribute to overall neuroinflammation in aging and neurodegenerative disease.
Nicholas E. Propson, Ethan R. Roy, Alexandra Litvinchuk, Jorg Köhl, Hui Zheng
Protection of the brain from viral infections involves the type I interferon (IFN-I) system, defects in which renders humans susceptible to herpes simplex encephalitis (HSE). However, excessive cerebral IFN-I levels leads to pathologies, suggesting the need for tight regulation of responses. Based on data from mouse models, human HSE cases, and primary cell culture systems, we here show that microglia and other immune cells undergo apoptosis in the HSV-1-infected brain through a mechanism dependent on the cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) pathway, but independent of IFN-I. HSV-1 infection of microglia induced cGAS-dependent apoptosis at high viral doses, while lower viral doses led to IFN-I responses. Importantly, inhibition of caspase activity prevented microglial cell death and augmented IFN-I responses. Accordingly, HSV-1-infected organotypic brain slices, or mice treated with caspase inhibitor, exhibited lower viral load and improved outcome of infection. Collectively, we identify an activation-induced apoptosis program in brain immune cells which down-modulates local immune responses.
Line S. Reinert, Ahmad S. Rashidi, Diana N. Tran, Georgios Katzilieris-Petras, Astrid K. Hvidt, Mette Gohr, Stefanie Fruhwürth, Chiranjeevi Bodda, Martin K. Thomsen, Mikkel H. Vendelbo, Ahmad Raza Khan, Brian Hansen, Petra Bergström, Lotta Agholme, Trine H. Mogensen, Maria H. Christensen, Jens R. Nyengaard, Ganes C. Sen, Henrik Zetterberg, Georges M.G.M. Verjans, Soren R. Paluden
Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost the CD8+ T cell-mediated cytotoxicity. However, this action is eventually dependent on the efficient recognition of tumor-specific antigens via T cell receptors. One primary mechanism by which tumor cells evade immune surveillance is to downregulate their antigen presentation. Little progress has been made towards harnessing potential therapeutic targets for enhancing antigen presentation on the tumor cell. Here, we identified MAL2 as a key player that determines the turnover of the antigen-loaded MHC-I complex and reduces the antigen presentation on tumor cells. MAL2 promotes the endocytosis of tumor antigens via direct interaction with the MHC-I complex and endosome-associated RAB proteins. In preclinical models, depletion of MAL2 in breast tumor cells profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that MAL2 is a potential therapeutic target for breast cancer immunotherapy.
Yuanzhang Fang, Lifei Wang, Changlin Wan, Yifan Sun, Kevin Van der Jeught, Zhuolong Zhou, Tianhan Dong, Ka Man So, Tao Yu, Yujing Li, Haniyeh Eyvani, Austyn Colter, Edward Dong, Sha Cao, Jin Wang, Bryan P. Schneider, George Sandusky, Yunlong Liu, Chi Zhang, Xiongbin Lu, Xinna Zhang
Diffuse intrinsic pontine glioma (DIPG) kills more children than any other type of brain tumor. Despite clinical trials testing many chemotherapeutic agents, palliative radiotherapy remains the standard treatment. Here, we utilized Cre/loxP technology to show that deleting Ataxia telangiectasia mutated (Atm) in primary mouse models of DIPG can enhance tumor radiosensitivity. Genetic deletion of Atm improved survival of mice with p53 deficient but not p53 wild-type gliomas following radiotherapy. Similar to patients with DIPG, mice with p53 wild-type tumors had improved survival after radiotherapy independent of Atm deletion. Primary p53 wild-type tumor cell lines induced proapoptotic genes after radiation and repressed the NRF2 target, NAD(P)H quinone dehydrogenase 1 (Nqo1). Tumors lacking p53 and Ink4a/Arf expressed the highest level of Nqo1 and were most resistant to radiation, but deletion of Atm enhanced the radiation response. These results suggest that tumor genotype may determine whether inhibition of ATM during radiotherapy will be an effective clinical approach to treat DIPGs.
Katherine Deland, Bryce F. Starr, Joshua S. Mercer, Jovita Byemerwa, Donna M. Crabtree, Nerissa T. Williams, Lixia Luo, Yan Ma, Mark Chen, Oren J. Becher, David G Kirsch
Dr. John Carethers discusses challenges to the advancement of underrepresented minorities in medicine and effective strategies for institutions to promote diversity. He proposes that diversity should be a fourth pillar in the mission of academic medicine, alongside research, education, and clinical care.
John M. Carethers
While corticosteroids dampen the dysregulated immune system and sometimes are prescribed as an adjunctive treatment for pneumonia, their effectiveness in the treatment of coronavirus 2019 (COVID-19) remains controversial. In this issue of the JCI, Liu and Zhang et al. evaluated corticosteroid treatment in more than 400 patients with severe COVID-19. The authors assessed subjects retrospectively for cardiac and liver injury, shock, ventilation, mortality, and viral clearance. Corticosteroids in severe COVID-19 related acute respiratory distress syndrome (ARDS) was associated with increased mortality and delayed viral clearance. Here, we consider how to reconcile the negative effects of corticosteroids revealed by Liu and Zhang et al. with the favorable effects (reduced mortality) that were described in the RECOVERY trial. We posit that treatment timing, dosage, and COVID-19 disease severity determine immune response and viral outcome. Patients with moderate-to-severe COVID-19 pneumonia are likely to benefit from moderate dose corticosteroid treatment when administered relatively late in the disease course.
Michael A. Matthay, Katherine D. Wick