Ammonium chloride reduces excitatory synaptic transmission onto CA1 pyramidal neurons of mouse organotypic slice cultures.

Acute liver dysfunction commonly leads to rapid increases in ammonia concentrations in both the serum and the cerebrospinal fluid. These elevations primarily affect brain astrocytes, causing modifications in their structure and function. However, its impact on neurons is not yet fully understood. In this study, we investigated the impact of elevated ammonium chloride levels (NH4Cl, 5 mM) on synaptic transmission onto CA1 pyramidal neurons in mouse organotypic entorhino-hippocampal tissue cultures. We found that acute exposure to NH4Cl reversibly reduced excitatory synaptic transmission and affected CA3-CA1 synapses. Notably, NH4Cl modified astrocytic, but not CA1 pyramidal neuron, passive intrinsic properties. To further explore the role of astrocytes in NH4Cl-induced attenuation of synaptic transmission, we used methionine sulfoximine to target glutamine synthetase, a key astrocytic enzyme for ammonia clearance in the central nervous system. Inhibition of glutamine synthetase effectively prevented the downregulation of excitatory synaptic activity, underscoring the significant role of astrocytes in adjusting excitatory synapses during acute ammonia elevation.

Unleashing T cell anti-tumor immunity: new potential for 5-Nonloxytryptamine as an agent mediating MHC-I upregulation in tumors.

BACKGROUND: New therapies are urgently needed in melanoma, particularly in late-stage patients not responsive to immunotherapies and kinase inhibitors. To uncover novel potentiators of T cell anti-tumor immunity, we carried out an ex vivo pharmacological screen and identified 5-Nonyloxytryptamine (5-NL), a serotonin agonist, as increasing the ability of T cells to target tumor cells. METHODS: The pharmacological screen utilized lymphocytic choriomeningitis virus (LCMV)-primed splenic T cells and melanoma B16.F10 cells expressing the LCMV gp33 CTL epitope. In vivo tumor growth in C57BL/6 J and NSG mice, in vivo antibody depletion, flow cytometry, immunoblot, CRISPR/Cas9 knockout, histological and RNA-Seq analyses were used to decipher 5-NL's immunomodulatory effects in vitro and in vivo. RESULTS: 5-NL delayed tumor growth in vivo and the phenotype was dependent on the hosts' immune system, specifically CD8+ T cells. 5-NL's pro-immune effects were not directly consequential to T cells. Rather, 5-NL upregulated antigen presenting machinery in melanoma and other tumor cells in vitro and in vivo without increasing PD-L1 expression. Mechanistic studies indicated that 5-NL's induced MHC-I expression was inhibited by pharmacologically preventing cAMP Response Element-Binding Protein (CREB) phosphorylation. Importantly, 5-NL combined with anti-PD1 therapy showed significant improvement when compared to single anti-PD-1 treatment. CONCLUSIONS: This study demonstrates novel therapeutic opportunities for augmenting immune responses in poorly immunogenic tumors.

Change in Metabolomic Profile Associated with an Average Increase in Plain Water Intake of >+ 1 L/Day, Sustained Over 4 Weeks, in Healthy Young Men with Initial Total Water Intake Below 2 L/Day.

Background/Aims: Cells adapt to chronic extracellular hypotonicity by altering metabolism. Corresponding effects of sustained hypotonic exposure at the whole-person level remain to be confirmed and characterized in clinical and population-based studies. This analysis aimed to 1) describe changes in urine and serum metabolomic profiles associated with four weeks of sustained > +1 L/d drinking water in healthy, normal weight, young men, 2) identify metabolic pathways potentially impacted by chronic hypotonicity, and 3) explore if effects of chronic hypotonicity differ by type of specimen and/or acute hydration condition. Materials: Untargeted metabolomic assays were completed for specimen stored from Week 1 and Week 6 of the Adapt Study for four men (20-25 years) who changed hydration classification during that period. Each week, first-morning urine was collected after overnight food and water restriction, and urine (t+60 min) and serum (t+90 min) were collected after a 750 mL bolus of drinking water. Metaboanalyst 5.0 was used to compare metabolomic profiles. Results: In association with four weeks of > + 1 L/d drinking water, urine osmolality decreased below 800 mOsm/kg H2O and saliva osmolality decreased below 100 mOsm/kg H2O. Between Week 1 and Week 6, 325 of 562 metabolic features in serum changed by 2-fold or more relative to creatinine. Based on hypergeometric test p-value <0.05 or Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway impact factor >0.2, the sustained > + 1 L/d of drinking water was associated with concurrent changes in carbohydrate, protein, lipid, and micronutrient metabolism, a metabolomic pattern of carbohydrate oxidation via the tricarboxylic acid (TCA) cycle, instead of glycolysis to lactate, and a reduction of chronic disease risk factors in Week 6. Similar metabolic pathways appeared potentially impacted in urine, but the directions of impact differed by specimen type. Conclusion: In healthy, normal weight, young men with initial total water intake below 2 L/d, sustained > + 1 L/d drinking water was associated with profound changes in serum and urine metabolomic profile, which suggested normalization of an aestivation-like metabolic pattern and a switch away from a Warburg-like pattern. Further research is warranted to pursue whole-body effects of chronic hypotonicity that reflect cell-level effects and potential beneficial effects of drinking water on chronic disease risk.

J-difference GABA-edited MRS reveals altered cerebello-thalamo-cortical metabolism in patients with hepatic encephalopathy.

Hepatic encephalopathy (HE) is a common neurological manifestation of liver cirrhosis and is characterized by an increase of ammonia in the brain accompanied by a disrupted neurotransmitter balance, including the GABAergic and glutamatergic systems. The aim of this study is to investigate metabolic abnormalities in the cerebello-thalamo-cortical system of HE patients using GABA-edited MRS and links between metabolite levels, disease severity, critical flicker frequency (CFF), motor performance scores, and blood ammonia levels. GABA-edited MRS was performed in 35 participants (16 controls, 19 HE patients) on a clinical 3 T MRI system. MRS voxels were placed in the right cerebellum, left thalamus, and left motor cortex. Levels of GABA+ and of other metabolites of interest (glutamine, glutamate, myo-inositol, glutathione, total choline, total NAA, and total creatine) were assessed. Group differences in metabolite levels and associations with clinical metrics were tested. GABA+ levels were significantly increased in the cerebellum of patients with HE. GABA+ levels in the motor cortex were significantly decreased in HE patients, and correlated with the CFF (r = 0.73; p < .05) and motor performance scores (r = -0.65; p < .05). Well-established HE-typical metabolite patterns (increased glutamine, decreased myo-inositol and total choline) were confirmed in all three regions and were closely linked to clinical metrics. In summary, our findings provide further evidence for alterations in the GABAergic system in the cerebellum and motor cortex in HE. These changes were accompanied by characteristic patterns of osmolytes and oxidative stress markers in the cerebello-thalamo-cortical system. These metabolic disturbances are a likely contributor to HE motor symptoms in HE. In patients with hepatic encephalopathy, GABA+ levels in the cerebello-thalamo-cortical loop are significantly increased in the cerebellum and significantly decreased in the motor cortex. GABA+ levels in the motor cortex strongly correlate with critical flicker frequency (CFF) and motor performance score (pegboard test tPEG), but not blood ammonia levels (NH3).

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation.

Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.

Sphingolipid subtypes differentially control proinsulin processing and systemic glucose homeostasis.

Impaired proinsulin-to-insulin processing in pancreatic ß-cells is a key defective step in both type 1 diabetes and type 2 diabetes (T2D) (refs. 1,2), but the mechanisms involved remain to be defined. Altered metabolism of sphingolipids (SLs) has been linked to development of obesity, type 1 diabetes and T2D (refs. 3-8); nonetheless, the role of specific SL species in ß-cell function and demise is unclear. Here we define the lipid signature of T2D-associated ß-cell failure, including an imbalance of specific very-long-chain SLs and long-chain SLs. ß-cell-specific ablation of CerS2, the enzyme necessary for generation of very-long-chain SLs, selectively reduces insulin content, impairs insulin secretion and disturbs systemic glucose tolerance in multiple complementary models. In contrast, ablation of long-chain-SL-synthesizing enzymes has no effect on insulin content. By quantitatively defining the SL-protein interactome, we reveal that CerS2 ablation affects SL binding to several endoplasmic reticulum-Golgi transport proteins, including Tmed2, which we define as an endogenous regulator of the essential proinsulin processing enzyme Pcsk1. Our study uncovers roles for specific SL subtypes and SL-binding proteins in ß-cell function and T2D-associated ß-cell failure.

Prognostic markers for the clinical course in the blood of patients with SARS-CoV-2 infection.

BACKGROUND: The presentation of peptides and the subsequent immune response depend on the MHC characteristics and influence the specificity of the immune response. Several studies have found an association between HLA variants and differential COVID-19 outcomes and have shown that HLA genotypes are associated with differential immune responses against SARS-CoV-2, particularly in severely ill patients. Information, whether HLA haplotypes are associated with the severity or length of the disease in moderately diseased individuals is absent. METHODS: Next-generation sequencing-based HLA typing was performed in 303 female and 231 male non-hospitalized North Rhine Westphalian patients infected with SARS-CoV2 during the first and second wave. For HLA-Class I, we obtained results from 528 patients, and for HLA-Class II from 531. In those patients, who became ill between March 2020 and January 2021, the 22 most common HLA-Class I (HLA-A, -B, -C) or HLA-Class II (HLA -DRB1/3/4, -DQA1, -DQB1) haplotypes were determined. The identified HLA haplotypes as well as the presence of a CCR5Δ32 mutation and number of O and A blood group alleles were associated to disease severity and duration of the disease. RESULTS: The influence of the HLA haplotypes on disease severity and duration was more pronounced than the influence of age, sex, or ABO blood group. These associations were sex dependent. The presence of mutated CCR5 resulted in a longer recovery period in males. CONCLUSION: The existence of certain HLA haplotypes is associated with more severe disease.

Hepatic encephalopathy.

Hepatic encephalopathy (HE) is a prognostically relevant neuropsychiatric syndrome that occurs in the course of acute or chronic liver disease. Besides ascites and variceal bleeding, it is the most serious complication of decompensated liver cirrhosis. Ammonia and inflammation are major triggers for the appearance of HE, which in patients with liver cirrhosis involves pathophysiologically low-grade cerebral oedema with oxidative/nitrosative stress, inflammation and disturbances of oscillatory networks in the brain. Severity classification and diagnostic approaches regarding mild forms of HE are still a matter of debate. Current medical treatment predominantly involves lactulose and rifaximin following rigorous treatment of so-called known HE precipitating factors. New treatments based on an improved pathophysiological understanding are emerging.

Acute cardiac side effects after COVID-19 mRNA vaccination: a case series.

BACKGROUND: Vaccination against SARS-CoV-2 has been the main tool to contain the pandemic. The rush development of the 3 vaccines and their expedited approval have led to inoculation of millions of patients around the world, leading to a containment of the disease. Despite continuous viral mutations and the identification of weaker variants, the severity of the infections has been mild, with many patients being either asymptomatic or recovering at home. Currently the focus has shifted from the host of organ damage related to the infection to potential side effects of the vaccine. Myocarditis has been reported as one of the potential side effects from the mRNA vaccine, affecting young healthy individuals. Up to September 30, 2021, 1.243 cases of myocarditis after vaccination with BNT162b2 Comirnaty© were registered in young adults by the Paul-Ehrlich-Institute in Germany alone. The exact pathophysiology and the risk factors for myocarditis following vaccination remain unclear. We present a case series of eight patients with cardiac symptom shortly after SARS-CoV-2 mRNA vaccination (BNT162b6, Biontech, Comirnaty© or mRNA-1237 Moderna, Spikevax©). PATIENTS AND METHODS: Eight patients between 13 and 56 years of age, vaccinated with either BNT162b2 or mRNA-1273 mRNA vaccine between January and August 2021 developed cardiac side effects shortly after either their first or second dose of the vaccine. Clinical data were retrieved from the clinical information system and analyzed. To support diagnosis of myocarditis or pericarditis, cardiac magnetic resonance imaging (MRI) was performed shortly after the onset of symptoms, with further investigations in severe cases. Symptoms were defined as dyspnea, chest pain and cardiac arrhythmia as determined by electrocardiography. RESULTS: Eight patients (5 males and 3 females) developed cardiac symptoms compatible with myocarditis, according to the CDC criteria, shortly after SARS-CoV-2 mRNA vaccination. Three patients (2 males, 1 female) required hospitalization due to severe chest pain and elevated troponin levels. All patients recovered fully within 7 days from the symptom onset. CONCLUSIONS: Our data suggest that cardiac adverse events such as myocarditis or pericarditis shortly after SARS-CoV-2 mRNA vaccination are rare but possible and occur particularly in male patients.

Risk-adjusted active tuberculosis case finding strategy in central Ethiopia.

Background: The World Health Organization recommends active case finding for tuberculosis (TB). Our study evaluated the targeted screening of household contacts (HHCs) of patients with contagious pulmonary tuberculosis (PTB) in Central Ethiopia. Methods: The HHCs of patients with microbiologically confirmed PTB were screened for TB symptoms and risk factors for TB transmission. Symptomatic HHCs were subjected to secondary investigation. Antimicrobial resistance was investigated among study participants. Results: Overall, 112 index patients with TB were included, and 289 HHCs from 89 households were screened. Multidrug-resistant-TB was detected in 2.7% (n=3) of index patients. The routine public health system process did not identify any TB suspects among HHCs. In total, 23.9% (n=69) of HHCs reported ≥1 TB symptom and PTB was confirmed in 2.1% (n=6). Reporting >1 TB symptom (relative risk [RR] 29.4, 95% CI 3.5-245.5, P<0.001) and night sweats (RR 27.1, 95% CI 3.2-226.6, P<0.001) were associated with the greatest relative risk. Regular alcohol consumption was identified as an individual risk factor for TB among HHCs (P=0.022). Conclusion: The MDR-TB rate among our patients was higher than recently reported for Ethiopia. Enhanced contact tracing using a risk-adjusted approach seems feasible and increases the case detection rate among HHCs of confirmed TB cases.

Swelling-induced upregulation of miR-141-3p inhibits hepatocyte proliferation.

Background & Aims: MicroRNAs (miRNAs) act as a regulatory mechanism on a post-transcriptional level by repressing gene transcription/translation and play a central role in the cellular stress response. Osmotic changes occur in a variety of diseases including liver cirrhosis and hepatic encephalopathy. Changes in cell hydration and alterations of the cellular volume are major regulators of cell function and gene expression. In this study, the modulation of hepatic gene expression in response to hypoosmolarity was studied. Methods: mRNA analyses of normo- and hypoosmotic perfused rat livers by gene expression arrays were used to identify miRNA and their potential target genes associated with cell swelling preceding cell proliferation. Selected miR-141-3p was also investigated in isolated hepatocytes treated with miRNA mimic, cell stretching, and after partial hepatectomy. Inhibitor perfusion studies were performed to unravel signalling pathways responsible for miRNA upregulation. Results: Using genome-wide transcriptomic analysis, it was shown that hypoosmotic exposure led to differential gene expression in perfused rat liver. Moreover, miR-141-3p was upregulated by hypoosmolarity in perfused rat liver and in primary hepatocytes. In concert with this, miR-141-3p upregulation was prevented after Src-, Erk-, and p38-MAPK inhibition. Furthermore, luciferase reporter assays demonstrated that miR-141-3p targets cyclin dependent kinase 8 (Cdk8) mRNA. Partial hepatectomy transiently upregulated miR-141-3p levels just after the initiation of hepatocyte proliferation, whereas Cdk8 mRNA was downregulated. The mechanical stretching of rat hepatocytes resulted in miR-141-3p upregulation, whereas Cdk8 mRNA tended to decrease. Notably, the overexpression of miR-141-3p inhibited the proliferation of Huh7 cells. Conclusions: Src-mediated upregulation of miR-141-3p was found in hepatocytes in response to hypoosmotic swelling and mechanical stretching. Because of its antiproliferative function, miR-141-3p may counter-regulate the proliferative effects triggered by these stimuli. Lay summary: In this study, we identified microRNA 141-3p as an osmosensitive miRNA, which inhibits proliferation during liver cell swelling. Upregulation of microRNA 141-3p, controlled by Src-, Erk-, and p38-MAPK signalling, results in decreased mRNA levels of various genes involved in metabolic processes, macromolecular biosynthesis, and cell cycle progression.

Physical Interaction between Embryonic Stem Cell-Expressed Ras (ERas) and Arginase-1 in Quiescent Hepatic Stellate Cells.

Embryonic stem cell-expressed Ras (ERas) is an atypical constitutively active member of the Ras family and controls distinct signaling pathways, which are critical, for instance, for the maintenance of quiescent hepatic stellate cells (HSCs). Unlike classical Ras paralogs, ERas has a unique N-terminal extension (Nex) with as yet unknown function. In this study, we employed affinity pull-down and quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses and identified 76 novel binding proteins for human and rat ERas Nex peptides, localized in different subcellular compartments and involved in various cellular processes. One of the identified Nex-binding proteins is the nonmitochondrial, cytosolic arginase 1 (ARG1), a key enzyme of the urea cycle and involved in the de novo synthesis of polyamines, such as spermidine and spermine. Here, we show, for the first time, a high-affinity interaction between ERas Nex and purified ARG1 as well as their subcellular colocalization. The inhibition of ARG1 activity strikingly accelerates the activation of HSCs ex vivo, suggesting a central role of ARG1 activity in the maintenance of HSC quiescence.

Single MHC-I Expression Promotes Virus-Induced Liver Immunopathology.

Major histocompatibility complex I (MHC-I) molecules present epitopes on the cellular surface of antigen-presenting cells to prime cytotoxic clusters of differentiation 8 (CD8)+ T cells (CTLs), which then identify and eliminate other cells such as virus-infected cells bearing the antigen. Human hepatitis virus cohort studies have previously identified MHC-I molecules as promising predictors of viral clearance. However, the underlying functional significance of these predictions is not fully understood. Here, we show that expression of single MHC-I isomers promotes virus-induced liver immunopathology. Specifically, using the lymphocytic choriomeningitis virus (LCMV) model system, we found MHC-I proteins to be highly up-regulated during infection. Deletion of one of the two MHC-I isomers histocompatibility antigen 2 (H2)-Db or H2-Kb in C57Bl/6 mice resulted in CTL activation recognizing the remaining MHC-I with LCMV epitopes in increased paucity. This increased CTL response resulted in hepatocyte death, increased caspase activation, and severe metabolic changes in liver tissue following infection with LCMV. Moreover, depletion of CTLs abolished LCMV-induced pathology in these mice with resulting viral persistence. In turn, natural killer (NK) cell depletion further increased antiviral CTL immunity and clearance of LCMV even in the presence of a single MHC-I isomer. Conclusion: Our results suggest that uniform MHC-I molecule expression promotes enhanced CTL immunity during viral infection and contributes to increased CTL-mediated liver cell damage that was alleviated by CD8 or NK cell depletion.

Hyperammonemia-induced changes in the cerebral transcriptome and proteome.

Molecular alterations underlying cerebral impairment in hyperammonemic disorders such as in hepatic encephalopathy (HE) are only poorly understood. Using transcriptomics and proteomics on brains of mice with systemic hyperammonemia resulting from knockout of hepatic glutamine synthetase (LGS-KO) we identified up to 214 genes and 34 proteins whose expressions were altered in brains of LGS-KO mice in a brain region-specific way. Differentially expressed genes were enriched for those related to oxidative stress, cell proliferation, heme metabolism and others. Due to their particularly high expression changes, coactivator associated arginine methyltransferase 1 (CARM1), TROVE2 and Lipocalin-2 (LCN2) were selected for further analyses. All selected candidates were expressed by astrocytes in rodent brain and challenging cultured astrocytes with NH4Cl changed their protein and mRNA levels similar to what was found in brains of LGS-KO mice. Further functional analyses suggested a role of CARM1 for senescence, TROVE2 for RNA quality control and LCN2 for disturbed iron homeostasis in ammonia-exposed astrocytes. LCN2 protein and Trove2 mRNA were also elevated in cerebral cortex of ammonium acetate-challenged rats and in post mortem brain tissue from patients with liver cirrhosis and HE, respectively. This study identified new molecular players potentially relevant for cerebral dysfunction in HE.

Prevalence and characterization of antimicrobial resistance among gram-negative bacteria isolated from febrile hospitalized patients in central Ethiopia.

BACKGROUND: Infectious diseases are among the leading causes of death in many low-income countries, such as Ethiopia. Without reliable local data concerning causative pathogens and antimicrobial resistance, empiric treatment is suboptimal. The objective of this study was to characterize gram-negative bacteria (GNB) as pathogens and their resistance pattern in hospitalized patients with infections in central Ethiopia. METHODS: Patients ≥ 1 year of age with fever admitted to the Asella Referral and Teaching Hospital from April 2016 to June 2018 were included. Blood and other appropriate clinical specimens were collected and cultured on appropriate media. Antibiotic susceptibility testing (AST) was performed using the Kirby-Bauer method and VITEK® 2. Species identification and detection of resistance genes were conducted using MALDI-ToF MS (VITEK® MS) and PCR, respectively. RESULTS: Among the 684 study participants, 54.2% were male, and the median age was 22.0 (IQR: 14-35) years. Blood cultures were positive in 5.4% (n = 37) of cases. Among other clinical samples, 60.6% (20/33), 20.8% (5/24), and 37.5% (3/8) of swabs/pus, urine and other body fluid cultures, respectively, were positive. Among 66 pathogenic isolates, 57.6% (n = 38) were GNB, 39.4% (n = 26) were gram-positive, and 3.0% (n = 2) were Candida species. Among the isolated GNB, 42.1% (16/38) were Escherichia coli, 23.7% (9/38) Klebsiella pneumoniae and 10.5% (4/38) Pseudomonas aeruginosa. In total, 27/38 gram-negative isolates were available for further analysis. Resistance rates were as follows: ampicillin/sulbactam, 92.6% (n = 25); cefotaxime, 88.9% (n = 24); ceftazidime, 74.1% (n = 20); cefepime, 74.1% (n = 20); gentamicin, 55.6% (n = 15); piperacillin/tazobactam, 48.1% (n = 13); meropenem, 7.4% (n = 2); and amikacin, 3.7% (n = 1). The blaNDM-1 gene was detected in one K. pneumoniae and one Acinetobacter baumannii isolate, which carried an additional blaOXA-51 gene. The ESBL enzymes were detected in 81.5% (n = 22) of isolates as follows: TEM, 77.2% (n = 17); CTX-M-1 group, 68.2% (n = 15); SHV group, 27.3% (n = 6); and CTX-M-9 group, 9.1% (n = 2). Based on the in vitro antimicrobial susceptibility results, empiric treatment initiated in 13 of 18 (72.2%) patients was likely ineffective. CONCLUSION: We report a high prevalence of ESBL-producing bacteria (81.5%) and carbapenem resistance (7.4%), with more than half of GNB carrying two or more ESBL enzymes resulting in suboptimal empiric antibiotic therapy. These findings indicate a need for local and national antimicrobial resistance surveillance and the strengthening of antimicrobial stewardship programs.

BAFF Attenuates Immunosuppressive Monocytes in the Melanoma Tumor Microenvironment.

Emerging evidence indicates B-cell activating factor (BAFF, Tnfsf13b) to be an important cytokine for antitumor immunity. In this study, we generated a BAFF-overexpressing B16.F10 melanoma cell model and found that BAFF-expressing tumors grow more slowly in vivo than control tumors. The tumor microenvironment (TME) of BAFF-overexpressing tumors had decreased myeloid infiltrates with lower PD-L1 expression. Monocyte depletion and anti-PD-L1 antibody treatment confirmed the functional importance of monocytes for the phenotype of BAFF-mediated tumor growth delay. RNA sequencing analysis confirmed that monocytes isolated from BAFF-overexpressing tumors were characterized by a less exhaustive phenotype and were enriched for in genes involved in activating adaptive immune responses and NF-κB signaling. Evaluation of patients with late-stage metastatic melanoma treated with inhibitors of the PD-1/PD-L1 axis demonstrated a stratification of patients with high and low BAFF plasma levels. Patients with high BAFF levels experienced lower responses to anti-PD-1 immunotherapies. In summary, these results show that BAFF, through its effect on tumor-infiltrating monocytes, not only impacts primary tumor growth but can serve as a biomarker to predict response to anti-PD-1 immunotherapy in advanced disease. SIGNIFICANCE: The BAFF cytokine regulates monocytes in the melanoma microenvironment to suppress tumor growth, highlighting the importance of BAFF in antitumor immunity.

Characterization of HIV-1 drug resistance among patients with failure of second-line combined antiretroviral therapy in central Ethiopia.

BACKGROUND: As a consequence of the improved availability of combined antiretroviral therapy (cART) in resource-limited countries, an emergence of HIV drug resistance (HIVDR) has been observed. We assessed the prevalence and spectrum of HIVDR in patients with failure of second-line cART at two HIV clinics in central Ethiopia. METHODS: HIV drug resistance was analysed in HIV-1-infected patients with virological failure of second-line cART using the geno2pheno application. RESULTS: Among 714 patients receiving second-line cART, 44 (6.2%) fulfilled the criteria for treatment failure and 37 were eligible for study inclusion. Median age was 42 years [interquartile range (IQR): 20-45] and 62.2% were male. At initiation of first-line cART, 23 (62.2%) were WHO stage III, mean CD4 cell count was 170.6 (range: 16-496) cells/µL and median (IQR) HIV-1 viral load was 30 220 (7963-82 598) copies/mL. Most common second-line cART regimens at the time of failure were tenofovir disoproxil fumarate (TDF)-lamivudine (3TC)-ritonavir-boosted atazanavir (ATV/r) (19/37, 51.4%) and zidovudine (ZDV)-3TC-ATV/r (9/37, 24.3%). Genotypic HIV-1 resistance testing was successful in 35 (94.6%) participants. We found at least one resistance mutation in 80% of patients and 40% carried a protease inhibitor (PI)-associated mutation. Most common mutations were M184V (57.1%), Y188C (25.7%), M46I/L (25.7%) and V82A/M (25.7%). High-level resistance against the PI ATV (10/35, 28.6%) and lopinavir (LPV) (5/35, 14.3%) was reported. As expected, no resistance mutations conferring integrase inhibitor resistance were detected. CONCLUSIONS: We found a high prevalence of resistance mutations, also against PIs (40%), as the national standard second-line cART components. Resistance testing before switching to second- or third-line cART is warranted.

Association of HLA genotypes, AB0 blood type and chemokine receptor 5 mutant CD195 with the clinical course of COVID-19.

BACKGROUND: COVID-19, the pandemic disease caused by infection with SARS-CoV-2, may take highly variable clinical courses, ranging from symptom-free and pauci-symptomatic to fatal disease. The goal of the current study was to assess the association of COVID-19 clinical courses controlled by patients' adaptive immune responses without progression to severe disease with patients' Human Leukocyte Antigen (HLA) genetics, AB0 blood group antigens, and the presence or absence of near-loss-of-function delta 32 deletion mutant of the C-C chemokine receptor type 5 (CCR5). PATIENT AND METHODS: An exploratory observational study including 157 adult COVID-19 convalescent patients was performed with a median follow-up of 250 days. The impact of different HLA genotypes, AB0 blood group antigens, and the CCR5 mutant CD195 were investigated for their role in the clinical course of COVID-19. In addition, this study addressed levels of severity and morbidity of COVID-19. The association of the immunogenetic background parameters were further related to patients' humoral antiviral immune response patterns by longitudinal observation. RESULTS: Univariate HLA analyses identified putatively protective HLA alleles (HLA class II DRB1*01:01 and HLA class I B*35:01, with a trend for DRB1*03:01). They were associated with reduced durations of disease instead decreased (rather than increased) total anti-S IgG levels. They had a higher virus neutralizing capacity compared to non-carriers. Conversely, analyses also identified HLA alleles (HLA class II DQB1*03:02 und HLA class I B*15:01) not associated with such benefit in the patient cohort of this study. Hierarchical testing by Cox regression analyses confirmed the significance of the protective effect of the HLA alleles identified (when assessed in composite) in terms of disease duration, whereas AB0 blood group antigen heterozygosity was found to be significantly associated with disease severity (rather than duration) in our cohort. A suggestive association of a heterozygous CCR5 delta 32 mutation status with prolonged disease duration was implied by univariate analyses but could not be confirmed by hierarchical multivariate testing. CONCLUSION: The current study shows that the presence of HLA class II DRB1*01:01 and HLA class I B*35:01 is of even stronger association with reduced disease duration in mild and moderate COVID-19 than age or any other potential risk factor assessed. Prospective studies in larger patient populations also including novel SARS-CoV-2 variants will be required to assess the impact of HLA genetics on the capacity of mounting protective vaccination responses in the future.