Association of BKV viremia and nephropathy with adverse alloimmune outcomes in kidney transplant recipients.

BACKGROUND: Immunosuppression reduction for BK polyoma virus (BKV) must be balanced against risk of adverse alloimmune outcomes. We sought to characterize risk of alloimmune events after BKV within context of HLA-DR/DQ molecular mismatch (mMM) risk score. METHODS: This single-center study evaluated 460 kidney transplant patients on tacrolimus-mycophenolate-prednisone from 2010-2021. BKV status was classified at 6-months post-transplant as "BKV" or "no BKV" in landmark analysis. Primary outcome was T-cell mediated rejection (TCMR). Secondary outcomes included all-cause graft failure (ACGF), death-censored graft failure (DCGF), de novo donor specific antibody (dnDSA), and antibody-mediated rejection (ABMR). Predictors of outcomes were assessed in Cox proportional hazards models including BKV status and alloimmune risk defined by recipient age and molecular mismatch (RAMM) groups. RESULTS: At 6-months post-transplant, 72 patients had BKV and 388 had no BKV. TCMR occurred in 86 recipients, including 27.8% with BKV and 17% with no BKV (p = .05). TCMR risk was increased in recipients with BKV (HR 1.90, (95% CI 1.14, 3.17); p = .01) and high vs. low-risk RAMM group risk (HR 2.26 (95% CI 1.02, 4.98); p = .02) in multivariable analyses; but not HLA serological MM in sensitivity analysis. Recipients with BKV experienced increased dnDSA in univariable analysis, and there was no association with ABMR, DCGF, or ACGF. CONCLUSIONS: Recipients with BKV had increased risk of TCMR independent of induction immunosuppression and conventional alloimmune risk measures. Recipients with high-risk RAMM experienced increased TCMR risk. Future studies on optimizing immunosuppression for BKV should explore nuanced risk stratification and may consider novel measures of alloimmune risk.

BK Viremia and Viruria Does Not Depend on the Type of Double-J Stent Used During Kidney Transplantation.

OBJECTIVES: BK virus is a major cause of chronic renal allograft failure.Transplant ureteral stent use has been reported as a risk factorfor BK virus infection. Recently, the use of a new type of ureteral stent (Magnetic Black Star) was reported in kidney transplant recipients. The aim ofthis preliminary report was to compare BK virus viremia and viruria occurrence depending on the type of double-J stent (standard versus Magnetic Black Star). MATERIALS AND METHODS: We included all kidney transplants performed in our center from January to December 2022. Each case had double-J stent placement. Indwelling stents were either a 6- or 7-Fr standard double-J stent or a 6-Fr Magnetic Black Star double-J stent. The type of double-J stent was chosen according to the surgeon's preference. A standard BK virus screening protocol was followed during the study period, which consisted of routine polymerase chain reaction examination of plasma and urine samples during monthly follow-ups. RESULTS: We assessed 120 patients without missing data: 92 patients received standard double-J stents and 28 patients received Magnetic Black Star stents. Patients were mostly male in the standard group (70.7%) versus the Magnetic Black Star group (42.9%) (P = .01). ABO- and HLA-incompatible transplant rates were similar in both groups. BK viremia occurrence and BK viruria occurrence were similar between groups at 1 month, 3 months, and 6 months. CONCLUSIONS: This preliminary study showed no differences concerning BKvirus infection depending on the type of double-J stents used during kidney transplant.

Outcomes of Kidneys Transplanted From Hepatitis C Viremic Donors to Naive Recipients From an Appalachian Rural Kidney Transplant Program.

OBJECTIVES: Before the advent of direct-acting antiviral therapy for hepatitis C virus, a large proportion of kidneys from donors with hepatitis C viremia were discarded. Hepatitis C virus is now amenable to effective treatment with excellent seronegativity rates. In this study, we review the outcomes of hepatitis C viremic kidneys transplanted into hepatitis C-naive recipients. MATERIALS AND METHODS: In this retrospective observational study, we examined 6 deceased donor kidneys with hepatitis C viremia that were transplanted into hepatitis C-naive recipients between March 2020 and April 2021 at a single center. Because of health insurance constraints, patients were treated for hepatitis C virus with glecaprevir/pibrentasvir for 8 weeks following seroconversion posttransplant. Primary outcome measured was viral seroconversion; secondary outcomes included graft function, posttransplant complications, and all-cause mortality. RESULTS: On average, patients seroconverted 6 days (range, 4-10 d) after transplant and began treatment 26 days (range, 15-37 d) after seroconversion. An 8-week course of antiviral treatment was successful in preventing acute hepatitis C virus infection in all patients. Posttransplant median creatinine was 1.96 mg/dL (range, 1-4.55 mg/dL), whereas median estimated glomerular filtration rate was 41.33 mL/min/1.73 m2 (range, 17-85 mL/min/1.73 m2). Patient survival rate was 66.7%, and death-censored graft survival rate was 100%. Two patients died from unrelated reasons: 1 from acute respiratory failure secondary to SARS-CoV-2 infection and 1 from posttransplant lymphoproliferative disorder. Two patients developed allograft rejection posttransplant (1 developed antibody mediated rejection, 1 developed borderline T-cell-mediated cellular rejection). Other major complications included neutropenia, fungal rash, SARS-CoV-2 infection, cytomegalovirus, BK virus, and Epstein-Barr virus reactivation. CONCLUSIONS: Use of hepatitis C-viremic donor kidneys for transplant is a safe option and has great potential to increase the kidney donor pool, as long as high index of suspicion is maintained for allograft rejection and opportunistic infections.

Host immunity associated with spontaneous suppression of viremia in therapy-naïve young rhesus macaques following neonatal SHIV infection.

IMPORTANCE: Despite the advent of highly active anti-retroviral therapy, people are still dying from HIV-related causes, many of whom are children, and a protective vaccine or cure is needed to end the HIV pandemic. Understanding the nature and activation states of immune cell subsets during infection will provide insights into the immunologic milieu associated with viremia suppression that can be harnessed via therapeutic strategies to achieve a functional cure, but these are understudied in pediatric subjects. We evaluated humoral and adaptive host immunity associated with suppression of viremia in rhesus macaques infected soon after birth with a pathogenic SHIV. The results from our study provide insights into the immune cell subsets and functions associated with viremia control in young macaques that may translate to pediatric subjects for the design of future anti-viral strategies in HIV-1-infected infants and children and contribute to an understudied area of HIV-1 pathogenesis in pediatric subjects.

Molecular Determinants of Mouse Adaptation of Rat Hepacivirus.

The lack of robust immunocompetent animal models for hepatitis C virus (HCV) impedes vaccine development and studies of immune responses. Norway rat hepacivirus (NrHV) infection in rats shares HCV-defining characteristics, including hepatotropism, chronicity, immune responses, and aspects of liver pathology. To exploit genetic variants and research tools, we previously adapted NrHV to prolonged infection in laboratory mice. Through intrahepatic RNA inoculation of molecular clones of the identified variants, we here characterized four mutations in the envelope proteins responsible for mouse adaptation, including one disrupting a glycosylation site. These mutations led to high-titer viremia, similar to that observed in rats. In 4-week-old mice, infection was cleared after around 5 weeks compared to 2 to 3 weeks for nonadapted virus. In contrast, the mutations led to persistent but attenuated infection in rats, and they partially reverted, accompanied by an increase in viremia. Attenuated infection in rat but not mouse hepatoma cells demonstrated that the characterized mutations were indeed mouse adaptive rather than generally adaptive across species and that species determinants and not immune interactions were responsible for attenuation in rats. Unlike persistent NrHV infection in rats, acute resolving infection in mice was not associated with the development of neutralizing antibodies. Finally, infection of scavenger receptor B-I (SR-BI) knockout mice suggested that adaptation to mouse SR-BI was not a primary function of the identified mutations. Rather, the virus may have adapted to lower dependency on SR-BI, thereby potentially surpassing species-specific differences. In conclusion, we identified specific determinants of NrHV mouse adaptation, suggesting species-specific interactions during entry. IMPORTANCE A prophylactic vaccine is required to achieve the World Health Organization's objective for hepatitis C virus elimination as a serious public health threat. However, the lack of robust immunocompetent animal models supporting hepatitis C virus infection impedes vaccine development as well as studies of immune responses and viral evasion. Hepatitis C virus-related hepaciviruses were discovered in a number of animal species and provide useful surrogate infection models. Norway rat hepacivirus is of particular interest, as it enables studies in rats, an immunocompetent and widely used small laboratory animal model. Its adaptation to robust infection also in laboratory mice provides access to a broader set of mouse genetic lines and comprehensive research tools. The presented mouse-adapted infectious clones will be of utility for reverse genetic studies, and the Norway rat hepacivirus mouse model will facilitate studies of hepacivirus infection for in-depth characterization of virus-host interactions, immune responses, and liver pathology.

Latency reversal plus natural killer cells diminish HIV reservoir in vivo.

HIV is difficult to eradicate due to the persistence of a long-lived reservoir of latently infected cells. Previous studies have shown that natural killer cells are important to inhibiting HIV infection, but it is unclear whether the administration of natural killer cells can reduce rebound viremia when anti-retroviral therapy is discontinued. Here we show the administration of allogeneic human peripheral blood natural killer cells delays viral rebound following interruption of anti-retroviral therapy in humanized mice infected with HIV-1. Utilizing genetically barcoded virus technology, we show these natural killer cells efficiently reduced viral clones rebounding from latency. Moreover, a kick and kill strategy comprised of the protein kinase C modulator and latency reversing agent SUW133 and allogeneic human peripheral blood natural killer cells during anti-retroviral therapy eliminated the viral reservoir in a subset of mice. Therefore, combinations utilizing latency reversal agents with targeted cellular killing agents may be an effective approach to eradicating the viral reservoir.

Episodic Detectable Viremia Does Not Affect Prognosis in Untreated Compensated Cirrhosis With Serum Hepatitis B Virus DNA <2,000 IU/mL.

INTRODUCTION: The necessity of antiviral therapy (AVT) for hepatitis B virus (HBV)-infected compensated cirrhosis with low-level viremia (LLV) is controversial. Herein, we evaluated its natural history. METHODS: From 3 tertiary hospitals, we enrolled untreated patients with compensated cirrhosis with persistent serum HBV-DNA levels <2,000 IU/mL; LLV was defined as having at least 1 detectable serum HBV-DNA (20-2,000 IU/mL) episode, whereas maintained virological response (MVR) was defined as having persistently undetectable serum HBV-DNA (<20 IU/mL). When serum HBV-DNA was ≥2,000 IU/mL during follow-up, AVT was administered according to guidelines. Study end points were development of cirrhotic complication event (CCE) or hepatocellular carcinoma (HCC). RESULTS: Among 567 patients analyzed, cumulative HCC risk at 3, 5, and 7 years was comparable between LLV (n = 391) vs MVR (n = 176) groups (5.7%, 10.7%, and 17.3% vs 7.2%, 15.5%, and 19.4%, respectively [P = 0.390]). CCE risk was also comparable between 2 groups (7.5%, 12.8%, and 13.7% vs 7.8%, 12.3%, and 14.6%, respectively [P = 0.880]). By multivariate analysis, LLV (vs MVR) was not associated with HCC or CCE risks, with adjusted hazard ratios of 1.422 (95% confidence interval [CI] 0.694-2.913; P = 0.336) and 1.816 (95% CI: 0.843-3.911; P = 0.128), respectively. Inverse probability of treatment weighting analysis yielded comparable outcomes between 2 groups, regarding HCC and CCE risks with hazard ratios of 0.903 (95% CI: 0.528-1.546; P = 0.711) and 1.192 (95% CI: 0.675-2.105; P = 0.545), respectively. DISCUSSION: Episodic LLV among untreated patients with compensated cirrhosis does not increase the risk of disease progression compared with MVR status. Thus, the benefits of AVT for episodic LLV should be re-evaluated.

Engagement of gcFKBP5/TRAF2 by spring viremia of carp virus to promote host cell apoptosis for supporting viral replication in grass carp.

Spring viremia of carp virus (SVCV) causes severe morbidity and mortality in grass carp (Ctenopharyngodon idellus) in Europe, America and several Asian countries. We found that FKBP5 (FK506-binding protein 5) is an SVCV infection response factor; however, its role in the innate immune mechanism caused by SVCV infection remains unknown. This study cloned gcFKBP5 (grass carp FKBP5) and made its mimic protein structure for function discussion. We found that gcFKBP5 expression in the primary innate immune organs of grass carp, including intestine, liver and spleen, was highly upregulated by SVCV in 24 h, with a similar result in fish cells by poly(I:C) treatment. gcFKBP overexpression aggravates viral damage to cells and increases viral replication. Furthermore, SVCV engages gcFKBP5 interacting with TRAF2 (tumour necrosis factor receptor-associated factor 2) to promote host cell apoptosis for supporting viral replication. The enhanced viral replication seems not to be due to the repression of IFN and other antiviral factors as expected. For the first time, these data show the pivotal role of gcFKBP5 in the innate immune response of grass carp to SVCV infection.

The Mouse Cytomegalovirus G Protein-Coupled Receptor Homolog, M33, Coordinates Key Features of In Vivo Infection via Distinct Components of Its Signaling Repertoire.

Common to all cytomegalovirus (CMV) genomes analyzed to date is the presence of G protein-coupled receptors (GPCR). Animal models of CMV provide insights into their role in viral fitness. The mouse cytomegalovirus (MCMV) GPCR, M33, facilitates dendritic cell (DC)-dependent viremia, the extravasation of blood-borne infected DCs to the salivary gland, and the frequency of reactivation events from latently infected tissue explants. Constitutive G protein-coupled M33 signaling is required for these phenotypes, although the contribution of distinct biochemical pathways activated by M33 is unknown. M33 engages Gq/11 to constitutively activate phospholipase C ß (PLCß) and downstream cyclic AMP response-element binding protein (CREB) in vitro. Identification of a MCMV M33 mutant (M33ΔC38) for which CREB signaling was disabled but PLCß activation was preserved provided the opportunity to investigate their relevance in vivo. Following intranasal infection with MCMV M33ΔC38, the absence of M33 CREB Gq/11-dependent signaling correlated with reduced mobilization of lytically-infected DCs to the draining lymph node high endothelial venules (HEVs) and reduced viremia compared with wild type MCMV. In contrast, M33ΔC38-infected DCs within the vascular compartment extravasated to the salivary glands via a pertussis toxin-sensitive, Gi/o-dependent, and CREB-independent mechanism. In the context of MCMV latency, spleen explants from M33ΔC38-infected mice were markedly attenuated for reactivation. Taken together, these data demonstrate that key features of the MCMV life cycle are coordinated in diverse tissues by distinct pathways of the M33 signaling repertoire. IMPORTANCE G protein-coupled receptors (GPCRs) act as cell surface molecular "switches" that regulate the cellular response to environmental stimuli. All cytomegalovirus (CMV) genomes analyzed to date possess GPCR homologs with phylogenetic evidence for independent gene capture events, signifying important in vivo roles. The mouse CMV (MCMV) GPCR homolog, designated M33, is important for cell-associated virus spread and the establishment and/or reactivation of latent MCMV infection. The signaling repertoire of M33 is distinct from cellular GPCRs and little is known of the relevance of component signaling pathways for in vivo M33 function. In this report, we showed that temporal and tissue-specific M33 signaling was required to facilitate in vivo infection. Understanding the relevance of the viral GPCR signaling profiles for in vivo function will provide opportunities for future targeted interventions.

A Possible Sterilizing Cure of HIV-1 Infection Without Stem Cell Transplantation.

BACKGROUND: A sterilizing cure of HIV-1 infection has been reported in 2 persons living with HIV-1 who underwent allogeneic hematopoietic stem cell transplantations from donors who were homozygous for the CCR5Δ32 gene polymorphism. However, this has been considered elusive during natural infection. OBJECTIVE: To evaluate persistent HIV-1 reservoir cells in an elite controller with undetectable HIV-1 viremia for more than 8 years in the absence of antiretroviral therapy. DESIGN: Detailed investigation of virologic and immunologic characteristics. SETTING: Tertiary care centers in Buenos Aires, Argentina, and Boston, Massachusetts. PATIENT: A patient with HIV-1 infection and durable drug-free suppression of HIV-1 replication. MEASUREMENTS: Analysis of genome-intact and replication-competent HIV-1 using near-full-length individual proviral sequencing and viral outgrowth assays, respectively; analysis of HIV-1 plasma RNA by ultrasensitive HIV-1 viral load testing. RESULTS: No genome-intact HIV-1 proviruses were detected in analysis of a total of 1.188 billion peripheral blood mononuclear cells and 503 million mononuclear cells from placental tissues. Seven defective proviruses, some of them derived from clonally expanded cells, were detected. A viral outgrowth assay failed to retrieve replication-competent HIV-1 from 150 million resting CD4+ T cells. No HIV-1 RNA was detected in 4.5 mL of plasma. LIMITATIONS: Absence of evidence for intact HIV-1 proviruses in large numbers of cells is not evidence of absence of intact HIV-1 proviruses. A sterilizing cure of HIV-1 can never be empirically proved. CONCLUSION: Genome-intact and replication-competent HIV-1 were not detected in an elite controller despite analysis of massive numbers of cells from blood and tissues, suggesting that this patient may have naturally achieved a sterilizing cure of HIV-1 infection. These observations raise the possibility that a sterilizing cure may be an extremely rare but possible outcome of HIV-1 infection. PRIMARY FUNDING SOURCE: National Institutes of Health and Bill & Melinda Gates Foundation.

Role of African Swine Fever Virus Proteins EP153R and EP402R in Reducing Viral Persistence in Blood and Virulence in Pigs Infected with BeninΔDP148R.

The limited knowledge on the role of many of the approximately 170 proteins encoded by African swine fever virus restricts progress toward vaccine development. Previously, the DP148R gene was deleted from the genome of genotype I virulent Benin 97/1 isolate. This virus, BeninΔDP148R, induced transient moderate clinical signs after immunization and high levels of protection against challenge. However, the BeninΔDP148R virus and genome persisted in blood over a prolonged period. In the current study, deletion of either EP402R or EP153R genes individually or in combination from BeninΔDP148R genome was shown not to reduce virus replication in macrophages in vitro. However, deletion of EP402R dramatically reduced the period of infectious virus persistence in blood in immunized pigs from 28 to 14 days and virus genome from 59 to 14 days while maintaining high levels of protection against challenge. The additional deletion of EP153R (BeninΔDP148RΔEP153RΔEP402R) further attenuated the virus, and no viremia or clinical signs were observed postimmunization. This was associated with decreased protection and detection of moderate levels of challenge virus in blood. Interestingly, the deletion of EP153R alone from BeninΔDP148R did not result in further virus attenuation and did not reduce the period of virus persistence in blood. These results show that EP402R and EP153R have a synergistic role in reducing clinical signs and levels of virus in blood. IMPORTANCE African swine fever virus (ASFV) causes a disease of domestic pigs and wild boar which results in death of almost all infected animals. The disease has a high economic impact, and no vaccine is available. We investigated the role of two ASFV proteins, called EP402R and EP153R, in determining the levels and length of time virus persists in blood from infected pigs. EP402R causes ASFV particles and infected cells to bind to red blood cells. Deletion of the EP402R gene dramatically reduced virus persistence in blood but did not reduce the level of virus. Deletion of the EP153R gene alone did not reduce the period or level of virus persistence in blood. However, deleting both EP153R and EP402R resulted in undetectable levels of virus in blood and no clinical signs showing that the proteins act synergistically. Importantly, the infected pigs were protected following infection with the wild-type virus that kills pigs.

Herpes DNAemia and TTV Viraemia in Intensive Care Unit Critically Ill Patients: A Single-Centre Prospective Longitudinal Study.

Introduction: We analysed blood DNAemia of TTV and four herpesviruses (CMV, EBV, HHV6, and HSV-1) in the REAnimation Low Immune Status Marker (REALISM) cohort of critically ill patients who had presented with either sepsis, burns, severe trauma, or major surgery. The aim was to identify common features related to virus and injury-associated pathologies and specific features linking one or several viruses to a particular pathological context. Methods: Overall and individual viral DNAemia were measured over a month using quantitative PCR assays from the 377 patients in the REALISM cohort. These patients were characterised by clinical outcomes [severity scores, mortality, Intensive Care Unit (ICU)-acquired infection (IAI)] and 48 parameters defining their host response after injury (cell populations, immune functional assays, and biomarkers). Association between viraemic event and clinical outcomes or immune markers was assessed using χ2-test or exact Fisher's test for qualitative variables and Wilcoxon test for continuous variables. Results: The cumulative incidence of viral DNAemia increased from below 4% at ICU admission to 35% for each herpesvirus during the first month. EBV, HSV1, HHV6, and CMV were detected in 18%, 12%, 10%, and 9% of patients, respectively. The incidence of high TTV viraemia (>10,000 copies/ml) increased from 11% to 15% during the same period. Herpesvirus viraemia was associated with severity at admission; CMV and HHV6 viraemia correlated with mortality during the first week and over the month. The presence of individual herpesvirus during the first month was significantly associated (p < 0.001) with the occurrence of IAI, whilst herpesvirus DNAemia coupled with high TTV viraemia during the very first week was associated with IAI. Herpesvirus viraemia was associated with a lasting exacerbated host immune response, with concurrent profound immune suppression and hyper inflammation, and delayed return to immune homeostasis. The percentage of patients presenting with herpesvirus DNAemia was significantly higher in sepsis than in all other groups. Primary infection in the hospital and high IL10 levels might favour EBV and CMV reactivation. Conclusion: In this cohort of ICU patients, phenotypic differences were observed between TTV and herpesviruses DNAemia. The higher prevalence of herpesvirus DNAemia in sepsis hints at further studies that may enable a better in vivo understanding of host determinants of herpesvirus viral reactivation. Furthermore, our data suggest that EBV and TTV may be useful as additional markers to predict clinical deterioration in ICU patients.

Siglec-9 defines and restrains a natural killer subpopulation highly cytotoxic to HIV-infected cells.

Siglec-9 is an MHC-independent inhibitory receptor expressed on a subset of natural killer (NK) cells. Siglec-9 restrains NK cytotoxicity by binding to sialoglycans (sialic acid-containing glycans) on target cells. Despite the importance of Siglec-9 interactions in tumor immune evasion, their role as an immune evasion mechanism during HIV infection has not been investigated. Using in vivo phenotypic analyses, we found that Siglec-9+ CD56dim NK cells, during HIV infection, exhibit an activated phenotype with higher expression of activating receptors and markers (NKp30, CD38, CD16, DNAM-1, perforin) and lower expression of the inhibitory receptor NKG2A, compared to Siglec-9- CD56dim NK cells. We also found that levels of Siglec-9+ CD56dim NK cells inversely correlate with viral load during viremic infection and CD4+ T cell-associated HIV DNA during suppressed infection. Using in vitro cytotoxicity assays, we confirmed that Siglec-9+ NK cells exhibit higher cytotoxicity towards HIV-infected cells compared to Siglec-9- NK cells. These data are consistent with the notion that Siglec-9+ NK cells are highly cytotoxic against HIV-infected cells. However, blocking Siglec-9 enhanced NK cells' ability to lyse HIV-infected cells, consistent with the known inhibitory function of the Siglec-9 molecule. Together, these data support a model in which the Siglec-9+ CD56dim NK subpopulation is highly cytotoxic against HIV-infected cells even whilst being restrained by the inhibitory effects of Siglec-9. To harness the cytotoxic capacity of the Siglec-9+ NK subpopulation, which is dampened by Siglec-9, we developed a proof-of-concept approach to selectively disrupt Siglec/sialoglycan interactions between NK and HIV-infected cells. We achieved this goal by conjugating Sialidase to several HIV broadly neutralizing antibodies. These conjugates selectively desialylated HIV-infected cells and enhanced NK cells' capacity to kill them. In summary, we identified a novel, glycan-based interaction that may contribute to HIV-infected cells' ability to evade NK immunosurveillance and developed an approach to break this interaction.

Patterns of serum immune biomarkers during elephant endotheliotropic herpesvirus viremia in Asian and African elephants.

Hemorrhagic disease (HD) caused by a group of elephant endotheliotropic herpesviruses (EEHV) is one of the leading causes of death for young elephants in human care. These viruses are widespread and typically persist latently in adult elephants with no negative effects; however, in juvenile Asian and more recently young African elephants, the onset of disease can be rapid and the mortality rate high. Measuring biomarkers associated with the immune response could be beneficial to understanding underlying disease processes, as well as the management of infection and HD. The goal of this study was to measure acute phase proteins and cytokines in serum collected from elephants infected with EEHV (13 Asian and 1 African) and compare concentrations according to presence, severity and outcome of disease. Serum amyloid A (SAA) and haptoglobin (HP) were higher in elephants with EEHV viremia than those without; concentrations increased with increasing viral load, and were higher in fatal cases compared to those that survived. In Asian elephants, SAA was also higher during EEHV1 viremia compared to EEHV5. Cytokine concentrations were typically low, and no statistical differences existed between groups. However, in individuals with detectable levels, longitudinal profiles indicated changes in tumor necrosis factor alpha (TNF-α) and interleukin-2 (IL-2) that may reflect an immune response to EEHV infection. However, the overall low concentrations detected using previously validated assays do not support the presence of a 'cytokine storm' and suggest more work is needed to understand if sub-optimal immune responses could be involved in disease progression. These results highlight the potential benefit of measuring circulating biomarker concentrations, such as APPs and cytokines, to improve our understanding of EEHV viremia and HD, assist with monitoring the progression of disease and determining the impact of interventions.

Correlation between low-level viremia and hepatitis B-related hepatocellular carcinoma and recurrence: a retrospective study.

BACKGROUND: Low-level viremia generally refers to detectable HBV DNA levels lower than 2000 IU/mL. Studies show that low-level viremia is a risk factor for hepatocellular carcinoma. The aim of this study was to explore the characteristics of low-level viremia patients with hepatitis B-related hepatocellular carcinoma and identify prognostic factors after curative hepatectomy. METHODS: Data from chronic hepatitis B patients with hepatocellular carcinoma receiving curative hepatectomy for the first time in the first hospital of China Medical University were studied. Patients were divided into two groups based on preoperative HBV DNA levels: group 1 (low-level viremia group, HBV DNA < 2000 IU/mL) and group 2 (HBV DNA ≥ 2000 IU/mL). RESULTS: Of the 212 patients, 104 patients were in group 1 and 108 patients were in group 2. There was a lower proportion of patients with HBsAg levels > 250 IU/mL (the upper limit of detection in our laboratory) in group 1 than in group 2 (71.2% vs. 86.1%, P < 0.01). The percentage of patients with a tumor diameter < 5 cm was 67.3% in group 1 and 37.0% in group 2 (P < 0.000). The percentage of tumor recurrence was 40.4% (42) in group 1 and 54.6% (59) in group 2 (P < 0.05). Median recurrence-free survival was 30.1 months in group 1 and 17.6 months in group 2 (P < 0.01). Multivariate analysis showed that a tumor diameter ≥ 5 cm (hazard ratio [HR] = 1.819, 95% confidence interval [CI] 1.193-2.775, P = 0.005), intrahepatic metastasis (HR = 1.916, 95% CI 1.077-3.407, P = 0.027), and an HBV DNA level ≥ 100 IU/mL (the lower limit of detection in our laboratory, HR = 2.943, 95% CI 1.916-4.520, P < 0.000) were independent prognostic factors associated with an increased risk of hepatocellular carcinoma recurrence. CONCLUSION: Preoperative low-level viremia was related with a long tumor recurrence interval and complete virologic response after curative hepatectomy was associated with a lower risk of hepatocellular carcinoma recurrence.

Evaluation of TTV replication as a biomarker of immune checkpoint inhibitors efficacy in melanoma patients.

Torque Teno Virus (TTV) is a small, non-enveloped, single-stranded and circular DNA virus that infects the majority of the population worldwide. Increased levels of plasma TTV viral load have been observed in various situations of immune deficiency or dysregulation, and several studies have suggested that TTV levels may be inversely correlated with immune competence. The measurement of TTV viremia by qPCR has been proposed as a potential biomarker for the follow-up of functional immune competence in immunosuppressed individuals, particularly hematopoietic stem cell transplant recipients. We hypothesized that TTV viral load could be used as a prognostic marker of immune checkpoint inhibitor (ICI) efficacy, and therefore investigated the TTV viral load in melanoma patients treated with nivolumab or pembrolizumab before and after 6 months of treatment. In the present study, TTV viral load was not different in melanoma patients before anti-PD-1 introduction compared to healthy volunteers, was not modified by ICI treatment and did not allowed to distinguish patients with treatment-sensitive tumor from patients with treatment-resistant tumor.

Is Monitoring of Cytomegalovirus Disease Required in Nontransplant Pediatric Acute Lymphoblastic Leukemia?

INTRODUCTION: Cytomegalovirus (CMV) infections in developing countries are experienced at an early age. This study was performed to investigate the frequency of reactivation and risk factors of infection acquired at an early age of nontransplant acute lymphoblastic leukemia (ALL) patients receiving immunosuppressive therapy with weekly monitoring of CMV levels in Turkey. MATERIALS AND METHODS: This was a retrospective, single-center study of 172 pediatric patients (102 boys and 70 girls) with ALL. All patients were monitored routinely for CMV-DNA at the initial presentation of leukemia and twice a week during chemotherapy. The CMV immunoglobulin (Ig)M/IgG titers were measured at admission. RESULTS: CMV seropositivity at baseline was 90,11%. The overall prevalence of CMV infection (viremia) was 70.34%, 116 of whom were seropositive for CMV IgG and 5 of whom were negative for CMV at the time of ALL diagnosis. Reactivation was more common than de novo CMV infections (P=0.000). CMV seropositivity at the beginning of the leukemia diagnosis was found to be an independent predictor for developing CMV infection (P=0.001). A total of 60 CMV infection episodes were treated with antivirals. Four of these included organ involvement. The duration of CMV-DNA viremia episodes was longer in patients with CMV-DNA ≥1000 copies/mL (n=45) than in those with lower CMV-DNA levels (P=0.002). Infection was shown not to be associated with chemotherapy phase. CONCLUSION: This study suggests the importance of monitoring for CMV infections in developing countries because of frequent reactivations in seropositive ALL patients. It should be kept in mind that low CMV-DNA levels may also lead to organ involvement.

SARS-CoV-2 viremia is associated with distinct proteomic pathways and predicts COVID-19 outcomes.

BACKGROUNDSARS-CoV-2 plasma viremia has been associated with severe disease and death in COVID-19 in small-scale cohort studies. The mechanisms behind this association remain elusive.METHODSWe evaluated the relationship between SARS-CoV-2 viremia, disease outcome, and inflammatory and proteomic profiles in a cohort of COVID-19 emergency department participants. SARS-CoV-2 viral load was measured using a quantitative reverse transcription PCR-based platform. Proteomic data were generated with Proximity Extension Assay using the Olink platform.RESULTSThis study included 300 participants with nucleic acid test-confirmed COVID-19. Plasma SARS-CoV-2 viremia levels at the time of presentation predicted adverse disease outcomes, with an adjusted OR of 10.6 (95% CI 4.4-25.5, P < 0.001) for severe disease (mechanical ventilation and/or 28-day mortality) and 3.9 (95% CI 1.5-10.1, P = 0.006) for 28-day mortality. Proteomic analyses revealed prominent proteomic pathways associated with SARS-CoV-2 viremia, including upregulation of SARS-CoV-2 entry factors (ACE2, CTSL, FURIN), heightened markers of tissue damage to the lungs, gastrointestinal tract, and endothelium/vasculature, and alterations in coagulation pathways.CONCLUSIONThese results highlight the cascade of vascular and tissue damage associated with SARS-CoV-2 plasma viremia that underlies its ability to predict COVID-19 disease outcomes.FUNDINGMark and Lisa Schwartz; the National Institutes of Health (U19AI082630); the American Lung Association; the Executive Committee on Research at Massachusetts General Hospital; the Chan Zuckerberg Initiative; Arthur, Sandra, and Sarah Irving for the David P. Ryan, MD, Endowed Chair in Cancer Research; an EMBO Long-Term Fellowship (ALTF 486-2018); a Cancer Research Institute/Bristol Myers Squibb Fellowship (CRI2993); the Harvard Catalyst/Harvard Clinical and Translational Science Center (National Center for Advancing Translational Sciences, NIH awards UL1TR001102 and UL1TR002541-01); and by the Harvard University Center for AIDS Research (National Institute of Allergy and Infectious Diseases, 5P30AI060354).

Zebrafish otud6b Negatively Regulates Antiviral Responses by Suppressing K63-Linked Ubiquitination of irf3 and irf7.

Ovarian tumor domain-containing 6B (OTUD6B) belongs to the OTU deubiquitylating enzyme family. In this study, we report that zebrafish otud6b is induced upon viral infection, and overexpression of otud6b suppresses cellular antiviral response. Disruption of otud6b in zebrafish increases the survival rate upon spring viremia of carp virus and grass carp reovirus exposure. Further assays indicate that otud6b interacts with irf3 and irf7 and diminishes traf6-mediated K63-linked polyubiquitination of irf3 and irf7. In addition, the OTU domain is required for otud6b to repress IFN-1 activation and K63-linked polyubiquitination of irf3 and irf7. Moreover, otud6b also attenuates tbk1 to bind to irf3 and irf7, resulting in the impairment of irf3 and irf7 phosphorylation. This study provides, to our knowledge, novel insights into otud6b function and sheds new lights on the regulation of irf3 and irf7 by deubiquitination in IFN-1 signaling.

In-depth single-cell analysis of translation-competent HIV-1 reservoirs identifies cellular sources of plasma viremia.

Clonal expansion of HIV-infected cells contributes to the long-term persistence of the HIV reservoir in ART-suppressed individuals. However, the contribution from cell clones that harbor inducible proviruses to plasma viremia is poorly understood. Here, we describe a single-cell approach to simultaneously sequence the TCR, integration sites and proviral genomes from translation-competent reservoir cells, called STIP-Seq. By applying this approach to blood samples from eight participants, we show that the translation-competent reservoir mainly consists of proviruses with short deletions at the 5'-end of the genome, often involving the major splice donor site. TCR and integration site sequencing reveal that cell clones with predicted pathogen-specificity can harbor inducible proviruses integrated into cancer-related genes. Furthermore, we find several matches between proviruses retrieved with STIP-Seq and plasma viruses obtained during ART and upon treatment interruption, suggesting that STIP-Seq can capture clones that are responsible for low-level viremia or viral rebound.