Reducing Read Time of Point-of-Care Test Does Not Affect Detection of Hepatitis C Virus and Reduces Need for Reflex RNA.

BACKGROUND & AIMS: Global elimination of hepatitis C virus (HCV) will require increases in diagnosis. Point of care (POC) tests that detect antibodies against HCV can be useful for testing large and difficult to reach populations. The most accurate POC test requires a 20 min read time to identify antibody-positive samples. We investigated whether viremic patients could be identified using a shorter read time, to increase efficiency and reduce the need for reflex tests (a follow-up test for HCV RNA on the same specimen to confirm viremia). METHODS: Patients with past or current HCV infections provided samples at 2 clinics in Canada for evaluation by the OraQuick HCV Rapid antibody POC test. A community HCV-screening program in Madrid, Spain (real-world cohort) invited people to be tested for HCV with the same OraQuick test. Patients provided samples of whole blood, via finger prick. Fingerprick samples were tested immediately after collection. In the clinic cohort, photographs of the developing test were taken at 15 second intervals, and blinded readers recorded the time to positivity. In the real-world cohort, readers recorded the OraQuick result at 5 minutes, and each minute after, up to 10 minutes, and then again at 20 minutes; viremia was then evaluated using a POC HCV RNA test (GeneXpert HCV Viral Load Assay). Sera from viremic and non-viremic clinic patients were used to quantify antibody titers to investigate the relationship between the time of band appearance and antibody concentration. Fisher's exact test and exact logistic regression were used to determine factors associated with a positive result at 5 minutes. RESULTS: Blood from all viremic patients produced a positive result in the antibody POC test by 5 min. Median time to a positive result for 171 viremic patients was 2.6 min (range, 1.8-4.6 min), vs 4.1 min (range, 2.3-14.4 min) for 108 patients with resolved infection (P < .001). The 5-min threshold identified all viremic cases among 176 HCV antibody-positive patients in the real-world cohort, confirmed by testing for HCV RNA. In the pooled cohorts, antibody positivity at 5 min identified viremic patients with 100% sensitivity (95% CI, 98.4%-100%); the negative predictive value was 100% (95% CI, 94.9%-100%). The positive predictive value at 5 min was 62.0% (95% CI, 56.7%-67.0%) and therefore insufficient alone to detect viremia; an HCV RNA test would still be necessary to confirm active infection. CONCLUSIONS: The wait time for the OraQuick HCV Rapid antibody POC blood test can be reduced from 20 min to 5 min and continue to reliably identify patients with HCV infection. Shortening the test time could increase high-throughput screening, reduce loss to follow up, and reduce the need for reflex HCV RNA testing.

Stromal TIMP3 regulates liver lymphocyte populations and provides protection against Th1 T cell-driven autoimmune hepatitis.

Lymphocyte infiltration into epithelial tissues and proinflammatory cytokine release are key steps in autoimmune disease. Although cell-autonomous roles of lymphocytes are well studied in autoimmunity, much less is understood about the stromal factors that dictate immune cell function. Tissue inhibitor of metalloproteinases 3 (TIMP3) controls systemic cytokine bioavailability and signaling by inhibiting the ectodomain shedding of cytokines and their receptors. The role of TIMP3 in cytokine biology is emerging; however, its contribution to cellular immunology remains unknown. In this study, we show that TIMP3 produced by the hepatic stroma regulates the basal lymphocyte populations in the liver and prevents autoimmune hepatitis. TIMP3 deficiency in mice led to spontaneous accumulation and activation of hepatic CD4(+), CD8(+), and NKT cells. Treatment with Con A in a model of polyclonal T lymphocyte activation resulted in a greatly enhanced Th1 cytokine response and acute liver failure, which mechanistically depended on TNF signaling. Bone marrow chimeras demonstrated that TIMP3 derived from the stromal rather than hematopoietic compartment provided protection against autoimmunity. Finally, we identified hepatocytes as the major source of Timp3 in a resting liver, whereas significant Timp3 gene transcription was induced by hepatic stellate cells in the inflamed liver. These results uncover metalloproteinase inhibitors as critical stromal factors in regulating cellular immunity during autoimmune hepatitis.

Differential Gene Expression in the Upper Respiratory Tract following Acute COVID-19 Infection in Ambulatory Patients That Develop Long COVID.

Background: Post-acute sequelae of COVID-19, or long COVID, is a condition characterized by persistent COVID-19 symptoms. As long COVID is defined by clinical criteria after an elapsed period, an opportunity for early intervention may aid in future prophylactic approaches; however, at present, the pathobiological mechanisms are multifactorial. By analyzing early virally infected upper respiratory tract tissue prior to eventual clinical diagnosis, it may be possible to identify biomarkers of altered immune response to facilitate future studies and interventions. Methods: This is a sub-group analysis of samples collected from those with confirmed COVID-19. RNA extraction from nasopharyngeal/mid-turbinate samples, sequencing, and bioinformatic analysis were performed to analyze long COVID and non-long COVID cohorts at day 14 post infection. Differences in mean viral load at various timepoints were analyzed as well as serological data. Results: We identified 26 upregulated genes in patients experiencing long COVID. Dysregulated pathways including complement and fibrinolysis pathways and IL-7 upregulation. Additionally, genes involved in neurotransmission were dysregulated, and the long COVID group had a significantly higher viral load and slower viral clearance. Conclusions: Uncovering early gene pathway abnormalities associated with eventual long COVID diagnosis may aid in early identification. We show that, post acute infection, in situ pathogenic deviations in viral response are associated with patients destined to meet consensus long COVID diagnosis that is entirely dependent on clinical factors. These results identify an important biological temporal window in the natural history of COVID-19 infection and long COVID pathogenesis amenable to testing from standard-of-care upper respiratory tract specimens.

Abnormal TNF activity in Timp3-/- mice leads to chronic hepatic inflammation and failure of liver regeneration.

Tumor-necrosis factor (TNF), a pleiotropic cytokine, triggers physiological and pathological responses in several organs. Here we show that deletion of the mouse gene Timp3 resulted in an increase in TNF-alpha converting enzyme activity, constitutive release of TNF and activation of TNF signaling in the liver. The increase in TNF in Timp3(-/-) mice culminated in hepatic lymphocyte infiltration and necrosis, features that are also seen in chronic active hepatitis in humans. This pathology was prevented when deletion of Timp3 was combined with Tnfrsf1a deficiency. In a liver regeneration model that requires TNF signaling, Timp3(-/-) mice succumbed to liver failure. Hepatocytes from Timp3(-/-) mice completed the cell cycle but then underwent cell death owing to sustained activation of TNF. This hepatocyte cell death was completely rescued by a neutralizing antibody to TNF. Dysregulation of TNF occurred specifically in Timp3(-/-), and not Timp1(-/-) mice. These data indicate that TIMP3 is a crucial innate negative regulator of TNF in both tissue homeostasis and tissue response to injury.

Leveraging COVID-19 vaccination to promote hepatitis C screening.

Health care initiatives, such as hepatitis C virus (HCV) screening, have been greatly overshadowed by the corona virus disease 2019 (COVID-19) pandemic. However, COVID-19 vaccination programs also provide an opportunity to engage with a high volume of people in a health care setting. We collaborated with a large COVID vaccination center to offer HCV point-of-care testing followed by dried blood spot collection for HCV RNA. Additionally, this opportunity was used to evaluate the practical significance of a 5-minute version of the OraQuick HCV antibody test in lieu of the standard 20-minute test. We tested 2317 individuals; 31 were HCV antibody positive and six were RNA positive of which four were treated and reached sustained virological response. Over a third of those surveyed said they would not have participated had the test required 20 minutes. Conclusion : Colocalizing HCV testing and linkage to care at a COVID vaccination clinic was found to be highly feasible; furthermore, a shortened antibody test greatly improves the acceptance of testing.

TIMP-3 recruits quiescent hematopoietic stem cells into active cell cycle and expands multipotent progenitor pool.

Regulating transition of hematopoietic stem cells (HSCs) between quiescent and cycling states is critical for maintaining homeostasis of blood cell production. The cycling states of HSCs are regulated by the extracellular factors such as cytokines and extracellular matrix; however, the molecular circuitry for such regulation remains elusive. Here we show that tissue inhibitor of metalloproteinase-3 (TIMP-3), an endogenous regulator of metalloproteinases, stimulates HSC proliferation by recruiting quiescent HSCs into the cell cycle. Myelosuppression induced TIMP-3 in the bone marrow before hematopoietic recovery. Interestingly, TIMP-3 enhanced proliferation of HSCs and promoted expansion of multipotent progenitors, which was achieved by stimulating cell-cycle entry of quiescent HSCs without compensating their long-term repopulating activity. Surprisingly, this effect did not require metalloproteinase inhibitory activity of TIMP-3 and was possibly mediated through a direct inhibition of angiopoietin-1 signaling, a critical mediator for HSC quiescence. Furthermore, bone marrow recovery from myelosuppression was accelerated by over-expression of TIMP-3, and in turn, impaired in TIMP-3-deficient animals. These results suggest that TIMP-3 may act as a molecular cue in response to myelosuppression for recruiting dormant HSCs into active cell cycle and may be clinically useful for facilitating hematopoietic recovery after chemotherapy or ex vivo expansion of HSCs.

A collaborative approach to hepatitis C testing in two First Nations communities of northwest Ontario.

Background: Two remote First Nations communities each collaborated with an urban-based liver clinic to organize wide-spread testing, followed by linkage to care for hepatitis C virus (HCV). Method: Involvement of community members was central to planning and conduct of the programs. Samples were obtained using dry blood spot cards (DBS). A week-long pilot study in Community 1 investigated the effectiveness of the program, using DBS. Community 2, being larger, more remote, and known to be endemic for HCV was more challenging. Three-week-long testing drives plus a stand-alone testing day were used to collect samples over 5 months. Public Health Agency (PHAC)'s National Laboratory for HIV Reference Services (NLHRS) received and tested the DBS samples for HCV and other blood-borne infections. Outcomes were measured by number of people tested, the quality of the tests, and community members' satisfaction with the program and retained knowledge about HCV, based on interviews. Results: In Community 1, 226 people were tested for HCV over 4 days. 85% agreed to human immunodeficiency virus (HIV) testing as well. In Community 2, 484 people, one-half of the adult population, were tested. Surveys of participants showed food was the most significant draw, and Facebook the most effective way to inform people of the events. Interviews with staff and participants showed a high level of satisfaction. Conclusion: The results suggest this is an effective approach to testing for HCV in unusually challenging settings. Lessons from the program include the power of community involvement; and the effectiveness of a highly targeted health initiative when developed through collaboration.

Birth cohort hepatitis C antibody prevalence in real-world screening settings in Ontario.

Background: Widespread screening and treatment of hepatitis C virus (HCV) is required to decrease late-stage liver disease and liver cancer. Clinical practice guidelines and Canadian Task Force on Preventative Health Care recommendations differ on the value of one-time birth cohort (1945-75) HCV screening in Canada. To assess the utility of this approach, we conducted a real-world analysis of HCV antibody (Ab) prevalence among birth cohort individuals seen in different clinical contexts. Methods: Cross-sectional study of individuals born between 1945 and 1975 who completed HCV Ab testing at multiple participating centres in Ontario, Canada between January 2016 and December 2020. Differences in prevalence were compared by year of birth, gender, and setting. Results: Among 16,672 birth cohort individuals tested, HCV Ab prevalence was 3.2%. Prevalence was higher among younger individuals which increased from 0.9% among those born between 1945 and 1956 to 4.6% among those born between 1966 and 1975. Prevalence was higher among males (4.4%) compared with females (2.0%) and differed by test site. In primary care, the prevalence was 0.5%, whereas the prevalence was highest among those tested at drug treatment centres (28.7%) and through community outreach (14.0%). Conclusions: HCV Ab prevalence remains high in the 1945-1975 birth cohort. These data highlight the need to re-evaluate existing Canadian Preventative Task Force recommendations, to consider incorporating one-time birth cohort and/or other population-based approaches to HCV screening into the clinical workflow as a preventative health measure, and to increase training among community providers to screen for and treat HCV.

Evaluation of Dried Blood Spot Testing for SARS-CoV-2 Serology Using a Quantitative Commercial Assay.

Dried blood spots (DBS) are commonly used for serologic testing for viruses and provide an alternative collection method when phlebotomy and/or conventional laboratory testing are not readily available. DBS collection could be used to facilitate widespread testing for SARS-CoV-2 antibodies to document past infection, vaccination, and potentially immunity. We investigated the characteristics of Roche's Anti-SARS-CoV-2 (S) assay, a quantitative commercial assay for antibodies against the spike glycoprotein. Antibody levels were reduced relative to plasma following elution from DBS. Quantitative results from DBS samples were highly correlated with values from plasma (r2 = 0.98), allowing for extrapolation using DBS results to accurately estimate plasma antibody levels. High concordance between plasma and fingerpick DBS was observed in PCR-confirmed COVID-19 patients tested 90 days or more after the diagnosis (45/46 matched; 1/46 mismatched plasma vs. DBS). The assessment of antibody responses to SARS-CoV-2 using DBS may be feasible using a quantitative anti-S assay, although false negatives may rarely occur in those with very low antibody levels.

Peginterferon lambda for the treatment of outpatients with COVID-19: a phase 2, placebo-controlled randomised trial.

BACKGROUND: To date, only monoclonal antibodies have been shown to be effective for outpatients with COVID-19. Interferon lambda-1 is a type III interferon involved in innate antiviral responses with activity against respiratory pathogens. We aimed to investigate the safety and efficacy of peginterferon lambda in the treatment of outpatients with mild-to-moderate COVID-19. METHODS: In this double-blind, placebo-controlled trial, outpatients with laboratory-confirmed COVID-19 were randomly assigned to a single subcutaneous injection of peginterferon lambda 180 µg or placebo within 7 days of symptom onset or first positive swab if asymptomatic. Participants were randomly assigned (1:1) using a computer-generated randomisation list created with a randomisation schedule in blocks of four. At the time of administration, study nurses received a sealed opaque envelope with the treatment allocation number. The primary endpoint was the proportion of patients who were negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA on day 7 after the injection, analysed by a χ2 test following an intention-to-treat principle. Prespecified analysis of the primary endpoint, adjusted for baseline viral load, using bivariate logistic regression was done. The trial is now complete. This trial is registered with ClinicalTrials.gov, NCT04354259. FINDINGS: Between May 18, and Sept 4, 2020, we recruited 30 patients per group. The decline in SARS-CoV-2 RNA was greater in those treated with peginterferon lambda than placebo from day 3 onwards, with a difference of 2·42 log copies per mL at day 7 (p=0·0041). By day 7, 24 (80%) participants in the peginterferon lambda group had an undetectable viral load, compared with 19 (63%) in the placebo group (p=0·15). After controlling for baseline viral load, patients in the peginterferon lambda group were more likely to have undetectable virus by day 7 than were those in the placebo group (odds ratio [OR] 4·12 [95% CI 1·15-16·73; p=0·029). Of those with baseline viral load above 106 copies per mL, 15 (79%) of 19 patients in the peginterferon lambda group had undetectable virus on day 7, compared with six (38%) of 16 in the placebo group (OR 6·25 [95% CI 1·49-31·06]; p=0·012). Peginterferon lambda was well tolerated, and adverse events were similar between groups with mild and transient aminotransferase, concentration increases more frequently observed in the peginterferon lambda group. Two individuals met the threshold of grade 3 increase, one in each group, and no other grade 3 or 4 laboratory adverse events were reported. INTERPRETATION: Peginterferon lambda accelerated viral decline in outpatients with COVID-19, increasing the proportion of patients with viral clearance by day 7, particularly in those with high baseline viral load. Peginterferon lambda has potential to prevent clinical deterioration and shorten duration of viral shedding. FUNDING: The Toronto COVID-19 Action Initiative, University of Toronto, and the Ontario First COVID-19 Rapid Research Fund, Toronto General & Western Hospital Foundation.

Hepatitis C Core-Antigen Testing from Dried Blood Spots.

In order to expand hepatitis C virus (HCV) screening, a change in the diagnostic paradigm is warranted to improve accessibility and decrease costs, such as utilizing dried blood spot (DBS) collection. In our study, blood from 68 patients with chronic HCV infection was spotted onto DBS cards and stored at the following temperatures for one week: -80 °C, 4 °C, 21 °C, 37 °C, and alternating 37 °C and 4 °C; to assess whether temperature change during transportation would affect sensitivity. Sample was eluted from the DBS cards and tested for HCV antibodies (HCV-Ab) and HCV core antigen (core-Ag). HCV-Abs were detected from 68/68 DBS samples at -80 °C, 4 °C, 21 °C, and 67/68 at 37 °C and alternating 37 °C and 4 °C. Sensitivity of core-Ag was as follows: 94% (-80 °C), 94% (4 °C), 91% (21 °C), 93% (37 °C), and 93% (37 °C/4 °C). Not only did temperature not greatly affect sensitivity, but sensitivities are higher than previously reported, and support the use of this assay as an alternative to HCV RNA. We then completed a head-to-head comparison (n = 49) of venous versus capillary samples, and one versus two DBS. No difference in core-Ag sensitivity was observed by sample type, but there was an improvement when using two spots. We conclude that HCV-Abs and core-Ag testing from DBS cards has high diagnostic accuracy and could be considered as an alternative to HCV RNA in certain settings.

Timp3 deficiency in insulin receptor-haploinsufficient mice promotes diabetes and vascular inflammation via increased TNF-alpha.

Activation of inflammatory pathways may contribute to the beginning and the progression of both atherosclerosis and type 2 diabetes. Here we report a novel interaction between insulin action and control of inflammation, resulting in glucose intolerance and vascular inflammation and amenable to therapeutic modulation. In insulin receptor heterozygous (Insr+/-) mice, we identified the deficiency of tissue inhibitor of metalloproteinase 3 (Timp3, an inhibitor of both TNF-alpha-converting enzyme [TACE] and MMPs) as a common bond between glucose intolerance and vascular inflammation. Among Insr+/- mice, those that develop diabetes have reduced Timp3 and increased TACE activity. Unchecked TACE activity causes an increase in levels of soluble TNF-alpha, which subsequently promotes diabetes and vascular inflammation. Double heterozygous Insr+/-Timp3+/- mice develop mild hyperglycemia and hyperinsulinemia at 3 months and overt glucose intolerance and hyperinsulinemia at 6 months. A therapeutic role for Timp3/TACE modulation is supported by the observation that pharmacological inhibition of TACE led to marked reduction of hyperglycemia and vascular inflammation in Insr+/- diabetic mice, as well as by the observation of increased insulin sensitivity in Tace+/- mice compared with WT mice. Our results suggest that an interplay between reduced insulin action and unchecked TACE activity promotes diabetes and vascular inflammation.

TIMP-3 deficiency leads to dilated cardiomyopathy.

BACKGROUND: Despite the mounting clinical burden of heart failure, the biomolecules that control myocardial tissue remodeling are poorly understood. TIMP-3 is an endogenous inhibitor of matrix metalloproteinases (MMPs) that has been found to be deficient in failing human myocardium. We hypothesized that TIMP-3 expression prevents maladaptive tissue remodeling in the heart, and accordingly, its deficiency in mice would alone be sufficient to trigger progressive cardiac remodeling and dysfunction similar to human heart failure. METHODS AND RESULTS: Mice with a targeted timp-3 deficiency were evaluated with aging and compared with age-matched wild-type littermates. Loss of timp-3 function triggered spontaneous LV dilatation, cardiomyocyte hypertrophy, and contractile dysfunction at 21 months of age consistent with human dilated cardiomyopathy. Its absence also resulted in interstitial matrix disruption with elevated MMP-9 activity, and activation of the proinflammatory tumor necrosis factor-alpha cytokine system, molecular hallmarks of human myocardial remodeling. CONCLUSIONS: TIMP-3 deficiency disrupts matrix homeostasis and the balance of inflammatory mediators, eliciting the transition to cardiac dilation and dysfunction. Therapeutic restoration of myocardial TIMP-3 may provide a novel approach to limit cardiac remodeling and the progression to failure in patients with dilated cardiomyopathy.

Ectodomain shedding of EGFR ligands and TNFR1 dictates hepatocyte apoptosis during fulminant hepatitis in mice.

The cell death receptor Fas plays a role in the establishment of fulminant hepatitis, a major cause of drug-induced liver failure. Fas activation elicits extrinsic apoptotic and hepatoprotective signals; however, the mechanisms by which these signals are integrated during disease are unknown. Tissue inhibitor of metalloproteinases 3 (TIMP3) controls the critical sheddase a disintegrin and metalloproteinase 17 (ADAM17) and may dictate stress signaling. Using mice and cells lacking TIMP3, ADAM17, and ADAM17-regulated cell surface molecules, we have found that ADAM17-mediated ectodomain shedding of TNF receptors and EGF family ligands controls activation of multiple signaling cascades in Fas-induced hepatitis. We demonstrated that TNF signaling promoted hepatotoxicity, while excessive TNF receptor 1 (TNFR1) shedding in Timp3-/- mice was protective. Compound Timp3-/-Tnf-/- and Timp3-/-Tnfr1-/- knockout conferred complete resistance to Fas-induced toxicity. Loss of Timp3 enhanced metalloproteinase-dependent EGFR signaling due to increased release of the EGFR ligands TGF-alpha, amphiregulin, and HB-EGF, while depletion of shed amphiregulin resensitized Timp3-/- hepatocytes to apoptosis. Finally, adenoviral delivery of Adam17 prevented acetaminophen-induced liver failure in a clinically relevant model of Fas-dependent fulminant hepatitis. These findings demonstrate that TIMP3 and ADAM17 cooperatively dictate cytokine signaling during death receptor activation and indicate that regulated metalloproteinase activity integrates survival and death signals during acute hepatotoxic stress.

Tissue inhibitor of metalloproteinase 3 regulates TNF-dependent systemic inflammation.

Host response to infectious agents must be rapid and powerful. One mechanism is the release of presynthesized membrane-bound TNF. TNF shedding is mediated by TNF-alpha converting enzyme, which is selectively inhibited by the tissue inhibitor of metalloproteinase 3 (TIMP3). We show that loss of TIMP3 impacts innate immunity by dysregulating cleavage of TNF and its receptors. Cultured timp3-/- macrophages release more TNF in response to LPS than wild-type macrophages. In timp3-/- mice, LPS causes serum levels of TNF and its receptors to rise more rapidly and remain higher compared with wild-type mice. The altered kinetics of ligand and receptor shedding enhances TNF signaling in timp3-/- mice, indicated by elevated serum IL-6. Physiologically, timp3-/- mice are more susceptible to LPS-induced mortality. Ablation of the TNF receptor gene p55 (Tnfrsf1a) or treatment with a synthetic metalloproteinase inhibitor rescues timp3-/- mice. Thus, TIMP3 is essential for normal innate immune function.

Lack of tissue inhibitor of metalloproteinases-3 results in an enhanced inflammatory response in antigen-induced arthritis.

Tissue inhibitor of metalloproteinases-3 (TIMP-3) is known to inhibit matrix metalloproteinases, aggrecanases, and tumor necrosis factor (TNF)-alpha-converting enzyme (TACE, ADAM17). These metalloproteases participate in different aspects of joint destruction in inflammatory arthritis. To determine the relative importance of this inhibitor in joint pathology, wild-type and Timp3-/- mice were immunized with methylated bovine serum albumin followed by arthritis induction by intra-articular injection of the same antigen. Animals were monitored for up to 14 days after challenge, and joint tissues were analyzed by routine and Safranin O staining and for the presence of aggrecan neoepitopes produced by metalloprotease cleavage. Serum TNF-alpha was measured by immunoassay. Compared to wild-type animals, Timp3-/- mice showed a dramatic increase in the initial inflammatory response to intra-articular antigen injection, and serum TNF-alpha levels were greatly elevated in the Timp3-/- animals after immunization. However, these differences in clinical features disappeared by days 7 to 14. No difference in Safranin O staining or aggrecan cleavage site neoepitope abundance was seen. Thus, in inflammatory joint disease TIMP-3 likely dampens the inflammatory response of TNF-alpha by reducing ADAM17 activity.