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1.
J Dermatol ; 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38619119

ABSTRACT

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, aberrant immune activation, and extensive tissue fibrosis of the skin and internal organs. Because of the complicated nature of its pathogenesis, the underlying mechanisms of SSc remain incompletely understood. Angiogenic factor with a G-patch domain and a Forkhead-associated domain 1 (AGGF1) is a critical factor in angiogenesis expressed on vascular endothelial cells, associated with inflammatory and fibrotic responses. To elucidate the possible implication of AGGF1 in SSc pathogenesis, we investigated the association between serum AGGF1 levels and clinical manifestations in SSc patients. We conducted a cross-sectional analysis of AGGF1 levels in sera from 60 SSc patients and 19 healthy controls with enzyme-linked immunosorbent assay. Serum AGGF1 levels in SSc patients were significantly higher than those in healthy individuals. In particular, diffuse cutaneous SSc patients with shorter disease duration had higher levels compared to those with longer disease duration and limited cutaneous SSc patients. Patients with higher serum AGGF1 levels had a higher incidence of digital ulcers, higher modified Rodnan Skin Scores (mRSS), elevated serum Krebs von den Lungen-6 (KL-6) levels, C-reactive protein levels, and right ventricular systolic pressures (RVSP) on the echocardiogram, whereas they had reduced percentage of vital capacity (%VC) and percentage of diffusing capacity of the lungs for carbon monoxide (%DLCO) in pulmonary functional tests. In line, serum AGGF1 levels were significantly correlated with mRSS, serum KL-6 and surfactant protein D levels, RVSP, and %DLCO. These results uncovered notable correlations between serum AGGF1 levels and key cutaneous and vascular involvements in SSc, suggesting potential roles of AGGF1 in SSc pathogenesis.

2.
medRxiv ; 2024 Mar 04.
Article in English | MEDLINE | ID: mdl-38496502

ABSTRACT

Strong sex differences in the frequencies and manifestations of Long COVID (LC) have been reported with females significantly more likely than males to present with LC after acute SARS-CoV-2 infection 1-7 . However, whether immunological traits underlying LC differ between sexes, and whether such differences explain the differential manifestations of LC symptomology is currently unknown. Here, we performed sex-based multi-dimensional immune-endocrine profiling of 165 individuals 8 with and without LC in an exploratory, cross-sectional study to identify key immunological traits underlying biological sex differences in LC. We found that female and male participants with LC experienced different sets of symptoms, and distinct patterns of organ system involvement, with female participants suffering from a higher symptom burden. Machine learning approaches identified differential sets of immune features that characterized LC in females and males. Males with LC had decreased frequencies of monocyte and DC populations, elevated NK cells, and plasma cytokines including IL-8 and TGF-ß-family members. Females with LC had increased frequencies of exhausted T cells, cytokine-secreting T cells, higher antibody reactivity to latent herpes viruses including EBV, HSV-2, and CMV, and lower testosterone levels than their control female counterparts. Testosterone levels were significantly associated with lower symptom burden in LC participants over sex designation. These findings suggest distinct immunological processes of LC in females and males and illuminate the crucial role of immune-endocrine dysregulation in sex-specific pathology.

4.
medRxiv ; 2024 Jan 12.
Article in English | MEDLINE | ID: mdl-38260484

ABSTRACT

Background: Long COVID contributes to the global burden of disease. Proposed root cause hypotheses include the persistence of SARS-CoV-2 viral reservoir, autoimmunity, and reactivation of latent herpesviruses. Patients have reported various changes in Long COVID symptoms after COVID-19 vaccinations, leaving uncertainty about whether vaccine-induced immune responses may alleviate or worsen disease pathology. Methods: In this prospective study, we evaluated changes in symptoms and immune responses after COVID-19 vaccination in 16 vaccine-naïve individuals with Long COVID. Surveys were administered before vaccination and then at 2, 6, and 12 weeks after receiving the first vaccine dose of the primary series. Simultaneously, SARS-CoV-2-reactive TCR enrichment, SARS-CoV-2-specific antibody responses, antibody responses to other viral and self-antigens, and circulating cytokines were quantified before vaccination and at 6 and 12 weeks after vaccination. Results: Self-report at 12 weeks post-vaccination indicated 10 out of 16 participants had improved health, 3 had no change, 1 had worse health, and 2 reported marginal changes. Significant elevation in SARS-CoV-2-specific TCRs and Spike protein-specific IgG were observed 6 and 12 weeks after vaccination. No changes in reactivities were observed against herpes viruses and self-antigens. Within this dataset, higher baseline sIL-6R was associated with symptom improvement, and the two top features associated with non-improvement were high IFN-ß and CNTF, among soluble analytes. Conclusions: Our study showed that in this small sample, vaccination improved the health or resulted in no change to the health of most participants, though few experienced worsening. Vaccination was associated with increased SARS-CoV-2 Spike protein-specific IgG and T cell expansion in most individuals with Long COVID. Symptom improvement was observed in those with baseline elevated sIL-6R, while elevated interferon and neuropeptide levels were associated with a lack of improvement.

5.
Nature ; 623(7985): 139-148, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37748514

ABSTRACT

Post-acute infection syndromes may develop after acute viral disease1. Infection with SARS-CoV-2 can result in the development of a post-acute infection syndrome known as long COVID. Individuals with long COVID frequently report unremitting fatigue, post-exertional malaise, and a variety of cognitive and autonomic dysfunctions2-4. However, the biological processes that are associated with the development and persistence of these symptoms are unclear. Here 275 individuals with or without long COVID were enrolled in a cross-sectional study that included multidimensional immune phenotyping and unbiased machine learning methods to identify biological features associated with long COVID. Marked differences were noted in circulating myeloid and lymphocyte populations relative to the matched controls, as well as evidence of exaggerated humoral responses directed against SARS-CoV-2 among participants with long COVID. Furthermore, higher antibody responses directed against non-SARS-CoV-2 viral pathogens were observed among individuals with long COVID, particularly Epstein-Barr virus. Levels of soluble immune mediators and hormones varied among groups, with cortisol levels being lower among participants with long COVID. Integration of immune phenotyping data into unbiased machine learning models identified the key features that are most strongly associated with long COVID status. Collectively, these findings may help to guide future studies into the pathobiology of long COVID and help with developing relevant biomarkers.


Subject(s)
Antibodies, Viral , Herpesvirus 4, Human , Hydrocortisone , Lymphocytes , Myeloid Cells , Post-Acute COVID-19 Syndrome , SARS-CoV-2 , Humans , Antibodies, Viral/blood , Antibodies, Viral/immunology , Biomarkers/blood , Cross-Sectional Studies , Herpesvirus 4, Human/immunology , Hydrocortisone/blood , Immunophenotyping , Lymphocytes/immunology , Machine Learning , Myeloid Cells/immunology , Post-Acute COVID-19 Syndrome/diagnosis , Post-Acute COVID-19 Syndrome/immunology , Post-Acute COVID-19 Syndrome/physiopathology , Post-Acute COVID-19 Syndrome/virology , SARS-CoV-2/immunology
7.
Neuron ; 110(20): 3278-3287.e8, 2022 10 19.
Article in English | MEDLINE | ID: mdl-36070749

ABSTRACT

Dysregulation of long interspersed nuclear element 1 (LINE-1, L1), a dominant class of transposable elements in the human genome, has been linked to neurodegenerative diseases, but whether elevated L1 expression is sufficient to cause neurodegeneration has not been directly tested. Here, we show that the cerebellar expression of L1 is significantly elevated in ataxia telangiectasia patients and strongly anti-correlated with the expression of epigenetic silencers. To examine the role of L1 in the disease etiology, we developed an approach for direct targeting of the L1 promoter for overexpression in mice. We demonstrated that L1 activation in the cerebellum led to Purkinje cell dysfunctions and degeneration and was sufficient to cause ataxia. Treatment with a nucleoside reverse transcriptase inhibitor blunted ataxia progression by reducing DNA damage, attenuating gliosis, and reversing deficits of molecular regulators for calcium homeostasis in Purkinje cells. Our study provides the first direct evidence that L1 activation can drive neurodegeneration.


Subject(s)
DNA Transposable Elements , Reverse Transcriptase Inhibitors , Animals , Humans , Mice , Ataxia/metabolism , Calcium/metabolism , Cerebellum/metabolism , Nucleosides/metabolism , Purkinje Cells/physiology , Reverse Transcriptase Inhibitors/metabolism , Long Interspersed Nucleotide Elements
8.
medRxiv ; 2022 Aug 10.
Article in English | MEDLINE | ID: mdl-35982667

ABSTRACT

SARS-CoV-2 infection can result in the development of a constellation of persistent sequelae following acute disease called post-acute sequelae of COVID-19 (PASC) or Long COVID 1-3 . Individuals diagnosed with Long COVID frequently report unremitting fatigue, post-exertional malaise, and a variety of cognitive and autonomic dysfunctions 1-3 ; however, the basic biological mechanisms responsible for these debilitating symptoms are unclear. Here, 215 individuals were included in an exploratory, cross-sectional study to perform multi-dimensional immune phenotyping in conjunction with machine learning methods to identify key immunological features distinguishing Long COVID. Marked differences were noted in specific circulating myeloid and lymphocyte populations relative to matched control groups, as well as evidence of elevated humoral responses directed against SARS-CoV-2 among participants with Long COVID. Further, unexpected increases were observed in antibody responses directed against non-SARS-CoV-2 viral pathogens, particularly Epstein-Barr virus. Analysis of circulating immune mediators and various hormones also revealed pronounced differences, with levels of cortisol being uniformly lower among participants with Long COVID relative to matched control groups. Integration of immune phenotyping data into unbiased machine learning models identified significant distinguishing features critical in accurate classification of Long COVID, with decreased levels of cortisol being the most significant individual predictor. These findings will help guide additional studies into the pathobiology of Long COVID and may aid in the future development of objective biomarkers for Long COVID.

9.
Cell ; 185(14): 2452-2468.e16, 2022 07 07.
Article in English | MEDLINE | ID: mdl-35768006

ABSTRACT

COVID survivors frequently experience lingering neurological symptoms that resemble cancer-therapy-related cognitive impairment, a syndrome for which white matter microglial reactivity and consequent neural dysregulation is central. Here, we explored the neurobiological effects of respiratory SARS-CoV-2 infection and found white-matter-selective microglial reactivity in mice and humans. Following mild respiratory COVID in mice, persistently impaired hippocampal neurogenesis, decreased oligodendrocytes, and myelin loss were evident together with elevated CSF cytokines/chemokines including CCL11. Systemic CCL11 administration specifically caused hippocampal microglial reactivity and impaired neurogenesis. Concordantly, humans with lasting cognitive symptoms post-COVID exhibit elevated CCL11 levels. Compared with SARS-CoV-2, mild respiratory influenza in mice caused similar patterns of white-matter-selective microglial reactivity, oligodendrocyte loss, impaired neurogenesis, and elevated CCL11 at early time points, but after influenza, only elevated CCL11 and hippocampal pathology persisted. These findings illustrate similar neuropathophysiology after cancer therapy and respiratory SARS-CoV-2 infection which may contribute to cognitive impairment following even mild COVID.


Subject(s)
COVID-19 , Influenza, Human , Neoplasms , Animals , Humans , Influenza, Human/pathology , Mice , Microglia/pathology , Myelin Sheath , Neoplasms/pathology , SARS-CoV-2
10.
Proc Natl Acad Sci U S A ; 119(20): e2011665119, 2022 05 17.
Article in English | MEDLINE | ID: mdl-35549556

ABSTRACT

APOBEC3A (A3A) is a cytidine deaminase that inactivates a variety of viruses through introduction of lethal mutations to the viral genome. Additionally, A3A can suppress HIV-1 transcription in a deaminase-independent manner by binding to the long terminal repeat of proviral HIV-1. However, it is unknown whether A3A targets additional host genomic loci for repression. In this study, we found that A3A suppresses gene expression by binding TTTC doublets that are in close proximity to each other. However, one TTTC motif is sufficient for A3A binding. Because TTTC doublets are present in interferon (IFN)-stimulated response elements (ISRE), we hypothesized that A3A may impact IFN-stimulated gene (ISG) expression. After scanning the human genome for TTTC doublet occurrences, we discovered that these motifs are enriched in the proximal promoters of genes associated with antiviral responses and type I IFN (IFN-I) signaling. As a proof of principle, we examined whether A3A can impact ISG15 expression. We found that A3A binding to the ISRE inhibits phosphorylated STAT-1 binding and suppresses ISG15 induction in response to IFN-I treatment. Consistent with these data, our RNA-sequencing analyses indicate that A3A loss results in increased IFN-I­dependent induction of several ISGs. This study revealed that A3A plays an unexpected role in ISG regulation and suggests that A3A contributes to a negative feedback loop during IFN signaling.


Subject(s)
Cytidine Deaminase , Cytokines , Gene Expression Regulation , Interferon-alpha , Ubiquitins , Cytidine Deaminase/genetics , Cytidine Deaminase/metabolism , Cytokines/genetics , Humans , Interferon-alpha/metabolism , Interferon-alpha/pharmacology , Response Elements , Ubiquitins/genetics
11.
BMC Cancer ; 22(1): 428, 2022 Apr 20.
Article in English | MEDLINE | ID: mdl-35443621

ABSTRACT

BACKGROUND: To evaluate the effect of regorafenib on soluble MHC class I polypeptide-related sequence A (MICA) (sMICA) level in vitro. In addition, we clinically examined whether its plasma levels were associated with regorafenib activity in terms of progression-free survival (PFS) in patients with CRC. METHODS: Human CRC cell line HCT116 and HT29 cells were treated with regorafenib and its pharmacologically active metabolites, M2 or M5 at the same concentrations as those in sera of patients. We also examined the sMICA levels and the area under the plasma concentration-time curve of regorafenib, M2 and M5. RESULTS: Regorafenib, M2, and M5 significantly suppressed shedding of MICA in human CRC cells without toxicity. This resulted in the reduced production of sMICA. In the clinical examination, patients with CRC who showed long median PFS (3.7 months) had significantly lower sMICA levels than those with shorter median PFS (1.2 months) (p = 0.045). CONCLUSIONS: MICA is an attractive agent for manipulating the immunological control of CRC and baseline sMICA levels could be a predictive biomarker for the efficacy of regorafenib treatment.


Subject(s)
Colorectal Neoplasms , Histocompatibility Antigens Class I , Biomarkers , Colorectal Neoplasms/drug therapy , Humans , Phenylurea Compounds/pharmacology , Phenylurea Compounds/therapeutic use , Pyridines
12.
Int J Urol ; 29(7): 647-655, 2022 07.
Article in English | MEDLINE | ID: mdl-35304776

ABSTRACT

OBJECTIVES: Pembrolizumab, an anti-PD-1 monoclonal antibody, revolutionized the treatment for advanced urothelial carcinoma. However, the standard treatment for patients after disease progression with pembrolizumab had not been established until the recent approval of enfortumab vedotin. We analyzed the treatment of these patients in the real world, and the patient background and outcomes. METHODS: We extracted data from 543 patients who experienced progressive disease after pembrolizumab initiation from a Japanese nation-wide cohort of platinum-refractory, metastatic urothelial carcinoma. RESULTS: The median overall survival of the 543 patients was 3.5 months (95% confidence interval 3.0-4.1). Of these, only 20.6% (n = 112) received chemotherapy as a subsequent systemic treatment after progressive disease. The regimen of chemotherapy was very diverse. The median overall survival was 11.9 months (95% confidence interval 9.2-14.7) for patients who received chemotherapy, compared to 2.4 months for those who did not receive chemotherapy (95% confidence interval 2.1-2.9; P < 0.0001). Patients who received subsequent chemotherapy were more likely to have better performance status, neutrophil-to-lymphocyte ratio <3, hemoglobin >11 mg/dL, and history of a single chemotherapeutic regimen at pembrolizumab initiation. CONCLUSIONS: This report highlights the real-world practice of the management after pembrolizumab treatment failure in the pre-enfortumab vedotin era, characterized by infrequent use of subsequent anticancer therapy comprising various regimens, reflecting the lack of a standard treatment. Clinical introduction of enfortumab vedotin is expected to improve treatment outcomes in this setting. The present study will provide important baseline data for evaluating the influence of enfortumab vedotin on clinical practices and outcomes.


Subject(s)
Carcinoma, Transitional Cell , Urinary Bladder Neoplasms , Urologic Neoplasms , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Carcinoma, Transitional Cell/drug therapy , Humans , Practice Patterns, Physicians' , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/pathology , Urologic Neoplasms/drug therapy , Urologic Neoplasms/pathology
13.
Nat Biotechnol ; 40(5): 681-691, 2022 05.
Article in English | MEDLINE | ID: mdl-35228707

ABSTRACT

As the biomedical community produces datasets that are increasingly complex and high dimensional, there is a need for more sophisticated computational tools to extract biological insights. We present Multiscale PHATE, a method that sweeps through all levels of data granularity to learn abstracted biological features directly predictive of disease outcome. Built on a coarse-graining process called diffusion condensation, Multiscale PHATE learns a data topology that can be analyzed at coarse resolutions for high-level summarizations of data and at fine resolutions for detailed representations of subsets. We apply Multiscale PHATE to a coronavirus disease 2019 (COVID-19) dataset with 54 million cells from 168 hospitalized patients and find that patients who die show CD16hiCD66blo neutrophil and IFN-γ+ granzyme B+ Th17 cell responses. We also show that population groupings from Multiscale PHATE directly fed into a classifier predict disease outcome more accurately than naive featurizations of the data. Multiscale PHATE is broadly generalizable to different data types, including flow cytometry, single-cell RNA sequencing (scRNA-seq), single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq), and clinical variables.


Subject(s)
COVID-19 , Single-Cell Analysis , Chromatin , Humans , Single-Cell Analysis/methods , Transposases , Exome Sequencing
14.
bioRxiv ; 2022 Jan 10.
Article in English | MEDLINE | ID: mdl-35043113

ABSTRACT

Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection. Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection - without neuroinvasion - and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function. Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.

16.
PLoS Biol ; 19(8): e3001373, 2021 08.
Article in English | MEDLINE | ID: mdl-34358229

ABSTRACT

Challenges in using cytokine data are limiting Coronavirus Disease 2019 (COVID-19) patient management and comparison among different disease contexts. We suggest mitigation strategies to improve the accuracy of cytokine data, as we learn from experience gained during the COVID-19 pandemic.


Subject(s)
COVID-19/immunology , COVID-19/therapy , COVID-19/epidemiology , Cytokines/immunology , Humans , Pandemics , Patient Care/methods , SARS-CoV-2/immunology
17.
Sci Signal ; 14(690)2021 07 06.
Article in English | MEDLINE | ID: mdl-34230210

ABSTRACT

Coronavirus disease 2019 (COVID-19) has poorer clinical outcomes in males than in females, and immune responses underlie these sex-related differences. Because immune responses are, in part, regulated by metabolites, we examined the serum metabolomes of COVID-19 patients. In male patients, kynurenic acid (KA) and a high KA-to-kynurenine (K) ratio (KA:K) positively correlated with age and with inflammatory cytokines and chemokines and negatively correlated with T cell responses. Males that clinically deteriorated had a higher KA:K than those that stabilized. KA inhibits glutamate release, and glutamate abundance was lower in patients that clinically deteriorated and correlated with immune responses. Analysis of data from the Genotype-Tissue Expression (GTEx) project revealed that the expression of the gene encoding the enzyme that produces KA, kynurenine aminotransferase, correlated with cytokine abundance and activation of immune responses in older males. This study reveals that KA has a sex-specific link to immune responses and clinical outcomes in COVID-19, suggesting a positive feedback between metabolites and immune responses in males.


Subject(s)
COVID-19/immunology , Kynurenic Acid/immunology , SARS-CoV-2 , Adult , Aged , COVID-19/blood , Case-Control Studies , Cytokine Release Syndrome/blood , Cytokine Release Syndrome/etiology , Cytokine Release Syndrome/immunology , Cytokines/blood , Cytokines/immunology , Female , Humans , Kynurenic Acid/blood , Logistic Models , Male , Metabolic Networks and Pathways/immunology , Metabolomics , Middle Aged , Multivariate Analysis , Severity of Illness Index , Sex Factors , Signal Transduction/immunology , Tryptophan/metabolism
18.
Hinyokika Kiyo ; 67(5): 191-195, 2021 May.
Article in Japanese | MEDLINE | ID: mdl-34126662

ABSTRACT

75 year-old man followed up regularly for the treatment of lung cancer came to our hospital with a chief complaint of general malaise. Blood test results showed deterioration in the renal function, and computed tomography (CT) confirmed left hydronephrosis. He was admitted to the hospital with the diagnosis of obstructive pyelonephritis. Despite antibiotic therapy after the left ureteral stent placement, CT on day 19 of hospitalization showed an enlarged soft tissue shadow along the renal pelvis and ureter, which was suspected to be peripelvic urinary extravasation caused by stent occlusion. We decided that conservative treatment would not improve his condition and conducted surgical therapy considering the possibility of malignancy. Intraoperatively, viscous and fragile tumor affected the renal pelvis and ureter. The operation resulted in left nephrectomy because radical resection was impossible. The pathological diagnosis was sarcomatoid urothelial carcinoma of the renal pelvis with ureter origin. He died due to multipleorgan failureon day 20 after theope ration. Were port a caseof sarcomatoid urothelial carcinoma in the upper urinary tract that was difficult to diagnose preoperatively based on imaging studies.


Subject(s)
Carcinoma, Transitional Cell , Kidney Neoplasms , Ureter , Ureteral Neoplasms , Carcinoma, Transitional Cell/diagnostic imaging , Carcinoma, Transitional Cell/surgery , Humans , Kidney Neoplasms/diagnostic imaging , Kidney Neoplasms/surgery , Kidney Pelvis/diagnostic imaging , Kidney Pelvis/surgery , Male , Nephrectomy , Ureteral Neoplasms/diagnostic imaging , Ureteral Neoplasms/surgery
19.
Science ; 371(6527): 347-348, 2021 Jan 22.
Article in English | MEDLINE | ID: mdl-33479140
20.
medRxiv ; 2020 Sep 08.
Article in English | MEDLINE | ID: mdl-32935119

ABSTRACT

Coronavirus disease-2019 (COVID-19) has poorer clinical outcomes in males compared to females, and immune responses underlie these sex-related differences in disease trajectory. As immune responses are in part regulated by metabolites, we examined whether the serum metabolome has sex-specificity for immune responses in COVID-19. In males with COVID- 19, kynurenic acid (KA) and a high KA to kynurenine (K) ratio was positively correlated with age, inflammatory cytokines, and chemokines and was negatively correlated with T cell responses, revealing that KA production is linked to immune responses in males. Males that clinically deteriorated had a higher KA:K ratio than those that stabilized. In females with COVID-19, this ratio positively correlated with T cell responses and did not correlate with age or clinical severity. KA is known to inhibit glutamate release, and we observed that serum glutamate is lower in patients that deteriorate from COVID-19 compared to those that stabilize, and correlates with immune responses. Analysis of Genotype-Tissue Expression (GTEx) data revealed that expression of kynurenine aminotransferase, which regulates KA production, correlates most strongly with cytokine levels and aryl hydrocarbon receptor activation in older males. This study reveals that KA has a sex-specific link to immune responses and clinical outcomes, in COVID-19 infection.

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