Growth hormone–secreting (GH-secreting) pituitary tumors are driven by oncogenes that induce cAMP signaling. In this issue of the JCI, Ben-Shlomo et al. performed a whole-exome study of pituitary adenomas. GH-secreting tumors had a high frequency of whole chromosome or chromosome arm copy number alterations and were associated with an increase in the tumor protein p53 and the cyclin-dependent kinase inhibitor p21WAF1/CIP1, which are findings consistent with induction of a response to DNA damage. Further, treatment of mouse pituitary cells with cAMP pathway agonists in vitro and in vivo elicited biomarkers of DNA replication stress or double-strand breaks. The findings of Ben Shlomo et al. indicate that oncoproteins that drive constitutively high cAMP signaling pathway output in susceptible cell types can elicit DNA replication stress and may promote genomic instability.
James A. Fagin, John H. Petrini
Tuberculosis (TB) continues to affect over 10 million people per year worldwide. Despite advances in diagnosis, smear microscopy insufficiently detects pulmonary disease, with test result reporting taking longer than a day. While urine assays to detect the lipopolysaccharide lipoarabinomannan (LAM), present in mycobacterial cell walls, can provide results within minutes, the currently available assay has low sensitivity and its application is limited to patients with HIV suspected of having TB. In this issue of the JCI, Broger and Nicol et al. investigated 3 rapid urine tests in 372 ambulatory HIV-negative individuals suspected of having TB in South Africa and Peru. FujiLAM emerged as a 25-minute test to confirm TB diagnosis in the HIV-seronegative population. This study shows that FujiLAM has considerable potential to reshape the TB diagnostics landscape, making diagnosis and treatment in one office visit a reality for TB.
Elisa H. Ignatius, Keira A. Cohen, William R. Bishai
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
The disease spectrum of coronavirus disease 2019 (COVID-19) ranges from no symptoms to multisystem failure and death. Characterization of virus-specific immune responses to severe acute respiratory coronavirus 2 (SARS-CoV-2) is key to understanding disease pathogenesis, but few studies have evaluated T cell immunity. In this issue of the JCI, Sattler et al. sampled blood from subjects with COVID-19 and analyzed the activation and function of virus antigen-specific CD4+ T cells. T cells that failed to respond to peptides from the membrane, spike or nucleocapsid proteins were more common in subjects who died. In those whose T cells had the capacity to respond, older patients with more co-morbidity had larger numbers of activated T cells compared with patients that had fewer risk factors, but these cells showed impaired IFN- production. This cross-sectional study relates activated T cell responses to patient risk factors and outcome. However, T cell response trajectory over the disease course remains an open question.
Diane E. Griffin
Allergic disorders include food allergy, allergic rhinitis, and certain forms of asthma resulting from the inappropriate development of immune responses to otherwise innocuous aeroallergens and foods. In this issue of the JCI, Thouvenot and Roitel et al. explore transcription infidelity as a mechanism that underlies the ability of these benign proteins to become allergens. Some foods and bioaerosols that produce allergies have RNA polymerase with a propensity to generate RNA gaps, thereby causing translational frameshifts. These frameshifts often create cationic carboxy-terminus residues that replace hydrophobic amino acids and have enhanced MHC binding, resulting in the tendency to provoke immune responses. IgE antibody responses initiated by these variant transcripts can later lead to IgE against the native molecule and also explain how anaphylaxis may occur in individuals who lacked specific IgE when tested using native protein reagents. This study has the potential to transform the diagnosis and treatment of allergic disorders.
Retinoic acid (RA) signaling is involved in various physiological and pathological conditions, including development, tumorigenesis, inflammation, and tissue damage and repair. In kidneys, the beneficial effect of RA has been reported in multiple disease models, such as glomerulosclerosis, renal fibrosis, and acute kidney injury. In this issue of the JCI, Chen et al. report a pathway activated by RA signaling that is mediated by the retinoic acid receptor responder protein 1 (RARRES1). Specifically, RARRES1, which is proteolytically cleaved to release the extracellular domain, was endocytosed by podocytes to induce apoptosis and glomerular dysfunction kidney disease. These findings unveil the contrasting aspects, a Janus face, of RA signaling that may guide its therapeutic use.
Qingqing Wei, Zheng Dong
NK cells are responsible for defense against viral infections and cancer. Although activated NK cells are armed to combat tumors, the tumor microenvironment (TME) contains ROS, which suppress NK cell antitumor activity. In this issue of the JCI, Yang, Neo, and colleagues explored NK cell resistance to oxidative stress in vitro and in human non–small-cell lung cancer (NSCLC). High surface thiol density and elevated expression of the ROS scavenger thioredoxin (Trx1) protected NK cells from ROS. Trx1 and thiol levels were higher in IL-15– than in IL-2–primed NK cells. Tumor-infiltrating Trx1+ NK cells were present in patients with NSCLC with elevated ROS levels in the tumor. Smokers scored higher for the ROS signature, which predicted poor prognosis, compared with nonsmokers. This study explains how activated NK cells survive in the ROS-rich TME and suggests that smokers with lung cancer may benefit from therapies using IL-15–primed NK cells.
Theresa L. Whiteside
In a stunningly short period of time, the unexpected coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has turned the unprepared world topsy-turvy. Although the rapidity with which the virus struck was indeed overwhelming, scientists throughout the world have also been up to the task of deciphering the mechanisms by which SARS-CoV-2 induces the multisystem- and multiorgan-inflammatory response that, collectively, contribute to the high mortality rate in affected individuals. In this issue of the JCI, Skendros et al., is one such team who report that the complement system plays a substantial role in creating the hyper-inflammation and thrombotic microangiopathy that appear to contribute to the severity of COVID-19. In support of the hypothesis that the complement system along with neutrophils and platelets contributes to COVID-19, the authors presented empirical evidence showing that treatment with the complement inhibitor, compstatin Cp-40, inhibited the expression of tissue factor in neutrophils. These results confirm that the complement axis plays a critical role and suggests that targeted therapy using complement inhibitors is a potential therapeutic option to treat COVID-19 induced inflammation.
Berhane Ghebrehiwet, Ellinor I. Peerschke
People with COVID-19 can develop pneumonia and severe inflammatory response with excessive cytokine release known as the cytokine storm. The Janus kinase inhibitor baricitinib used to treat rheumatoid arthritis reduces inflammation by modifying the cytokine pathway. In this issue of the JCI, Bronte and Ugel et al. performed an observational longitudinal study to evaluated the use of baricitinib in 20 patients with COVID-19. Treated subjects showed reduced levels of plasma interleukin (IL)-6, tumor necrosis factor (TNF), IL-1β and phosphorylated STAT3 and swift lymphocyte restoration. Notably, these patients had a dramatically favorable clinical outcome. While bias can plague uncontrolled research, this study has biological credibility and warrants randomized control studies.
David L. Thomas
Idiopathic CD4+ T cell lymphocytopenia (ICL) is a heterogeneous syndrome presenting with persistent CD4+ T cell lymphopenia of unknown origin, and opportunistic infections in some patients. The underlying pathogenesis and appropriate management remain understudied. In this issue of the JCI, Perez-Diez and Wong et al. assessed the prevalence of autoantibodies from the sera of 51 adult ICL patients (out of a cohort of 72). Some patients showed high levels of IgG and IgM autoantibodies against numerous autoantigens, and some autoantibodies were specific for lymphocytes. The researchers implicate these autoantibodies as a possible pathogenic mechanism responsible for the reduction in circulating CD4+ T cells. This study goes beyond defining a mechanism in a complex, poorly defined disease; it also brings a renewed focus on ICL that will likely result in improved diagnostic evaluation and treatment.
Jose S. Campos, Sarah E. Henrickson, Roshini S. Abraham
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