Plasma Antigen Research Articles

Circulating Naturally-Occurring Anticoagulants before Treatment and after Recovery from SARS-CoV-2 Infection in Ghana

Background: Disturbance in naturally-occurring anticoagulants may contribute to the hypercoagulable state in COVID-19. This study determined the plasma antigen levels of protein C (PC), protein S (PS), antithrombin-III (AT-III), and thrombomodulin (TM) before treatment and after recovery from COVID-19. Materials and Methods: This cross-sectional study, conducted from February to August 2022 at Kumasi South Hospital, recruited sixty-five RT-PCR-confirmed COVID-19 participants. A venous blood sample was taken for full blood count (FBC) analysis using a 3-part fully automated haematology analyzer, and PC, PS, AT-III, and TM antigen levels measured using ELISA. The data were analyzed using SPSS version 26.0. P<0.05 was considered statistically significant. Results: Severe COVID-19 participants had relatively lower haemoglobin (p<0.001), RBC (p<0.001), HCT% (p<0.001) and platelets (p<0.001), but higher RDW-CV% (p=0.013), WBC (p<0.001), and absolute lymphocyte counts (p<0.001) compared to those with the non-severe form of the disease. The overall prevalence of anaemia among the participants was 58.5%, and 32 (84.2%) and 6 (15.8%) of the anaemic participants had mild and moderate anaemia respectively. Protein C (p<0.001), PS (p<0.001) and ATIII (p<0.001) levels were lower among the severe COVID-19 participants than in the non-severe group. But severe COVID-19 group had higher TM levels (p<0.001) than the non-severe group. Again, participants had higher haemoglobin (p<0.001), RBC (p<0.001), HCT% (p=0.049), absolute neutrophil count (p<0.001) and platelets (p<0.001) after recovery from COVID-19 than the values on admission. Additionally, after recovery, participants had higher levels of PC (p<0.001), PS (p<0.001), and ATIII (p<0.001), but reduced TM (p<0.001). Conclusion: Severe COVID-19 patients had higher PC, PS, and AT-III, but lower TM levels. The changes in circulating anticoagulants may contribute to the hypercoagulable state of COVID-19. Blood cell indices are negatively affected during COVID-19. Complete recovery from the SARS-CoV-2 infection normalised the haematological indices. Assessment of naturally-occurring anticoagulants and the provision of anticoagulants are recommended in the management of COVID-19. Doi: 10.28991/SciMedJ-2022-04-04-01 Full Text: PDF

CTLA4-Linked Autoimmunity in the Pathogenesis of Endometriosis and Related Infertility: A Systematic Review.

Several studies, although with conflicting results, have sought to determine the concentration of soluble CTLA4 antigens in peripheral blood plasma and peritoneal fluid in patients with endometriosis-related infertility. A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) through a search of the following databases: MEDLINE, EMBASE, Global Health, The Cochrane Library, Health Technology Assessment Database and Web of Science, and Clinical Trials research register. We included observational or prospective human and animal studies with any features related to endometriosis and/or infertility studies involving CTLA4-related pathogenesis published in English. The results of studies in which the size and characteristics of the observed groups were not stated were excluded. From the initial pool of 73 publications identified and screened, we finally included 5 articles to summarize the most recent knowledge about CTLA4-linked autoimmunity in the pathogenesis of endometriosis and related infertility. Evidence from clinical studies shows that CTLA4-based autoimmunity is involved in the maintenance of chronic inflammation in the peritoneal environment, with pre-clinical evidence of anti-CTLA antibodies as a potential novel target therapy for endometriosis. However, CTLA4 gene analyses do not support findings of CTLA4-linked autoimmunity as a primary determinant of the pathogenesis of endometriosis. These findings underlie the role of complex interactions within the family of immune checkpoint molecules involved. Further studies are needed to investigate the clinical relevance of anti-CTLA target therapy, taking into account the potential adverse events and repercussions of novel immunologic therapy modalities. However, with the general scarcity of studies investigating this topic, the clinical importance of CTLA4 autoimmunity still remains unclear.

The Association of Baseline Plasma SARS-CoV-2 Nucleocapsid Antigen Level and Outcomes in Patients Hospitalized With COVID-19.

Levels of plasma SARS-CoV-2 nucleocapsid (N) antigen may be an important biomarker in patients with COVID-19 and enhance our understanding of the pathogenesis of COVID-19. To evaluate whether levels of plasma antigen can predict short-term clinical outcomes and identify clinical and viral factors associated with plasma antigen levels in hospitalized patients with SARS-CoV-2. Cross-sectional study of baseline plasma antigen level from 2540 participants enrolled in the TICO (Therapeutics for Inpatients With COVID-19) platform trial from August 2020 to November 2021, with additional data on day 5 outcome and time to discharge. 114 centers in 10 countries. Adults hospitalized for acute SARS-CoV-2 infection with 12 days or less of symptoms. Baseline plasma viral N antigen level was measured at a central laboratory. Delta variant status was determined from baseline nasal swabs using reverse transcriptase polymerase chain reaction. Associations between baseline patient characteristics and viral factors and baseline plasma antigen levels were assessed using both unadjusted and multivariable modeling. Association between elevated baseline antigen level of 1000 ng/L or greater and outcomes, including worsening of ordinal pulmonary scale at day 5 and time to hospital discharge, were evaluated using logistic regression and Fine-Gray regression models, respectively. Plasma antigen was below the level of quantification in 5% of participants at enrollment, and 1000 ng/L or greater in 57%. Baseline pulmonary severity of illness was strongly associated with plasma antigen level, with mean plasma antigen level 3.10-fold higher among those requiring noninvasive ventilation or high-flow nasal cannula compared with room air (95% CI, 2.22 to 4.34). Plasma antigen level was higher in those who lacked antispike antibodies (6.42 fold; CI, 5.37 to 7.66) and in those with the Delta variant (1.73 fold; CI, 1.41 to 2.13). Additional factors associated with higher baseline antigen level included male sex, shorter time since hospital admission, decreased days of remdesivir, and renal impairment. In contrast, race, ethnicity, body mass index, and immunocompromising conditions were not associated with plasma antigen levels. Plasma antigen level of 1000 ng/L or greater was associated with a markedly higher odds of worsened pulmonary status at day 5 (odds ratio, 5.06 [CI, 3.41 to 7.50]) and longer time to hospital discharge (median, 7 vs. 4 days; subhazard ratio, 0.51 [CI, 0.45 to 0.57]), with subhazard ratios similar across all levels of baseline pulmonary severity. Plasma samples were drawn at enrollment, not hospital presentation. No point-of-care test to measure plasma antigen is currently available. Elevated plasma antigen is highly associated with both severity of pulmonary illness and clinically important patient outcomes. Multiple clinical and viral factors are associated with plasma antigen level at presentation. These data support a potential role of ongoing viral replication in the pathogenesis of SARS-CoV-2 in hospitalized patients. U.S. government Operation Warp Speed and National Institute of Allergy and Infectious Diseases.

Alteration of Some Sperm Proteins, Anti-oxidants, and Prostate-specific Antigen in the Seminal Plasma of Bacteriospermic Infertile Males

Aim: To investigate the alteration of some sperm proteins, anti-oxidants, and prostate-specific antigen in the seminal plasma of bacteriospermic infertile males.
 Study Design: The study is a case-control design to investigate the semen parameters and some sperm proteins in infertile males with bacteriospermia attending urology or fertility clinics in Port Harcourt, Rivers State, Nigeria.
 Place and Duration of Study: The study was carried out in the Department of Medical Laboratory Science, Rivers State University, Port Harcourt. However, some of the Laboratory investigations were done in the Chemical Pathology Unit and Medical Microbiology Unit of the University of Port Harcourt Teaching Hospital, Port Harcourt. The Study was between the period of September 2019 and Feb. 2022.
 Methodology: A total 193 subjects were recruited of which 76 were fertile without bacterial infection, 24 were fertile with bacterial infection, 37 infertile without bacterial infection and 56 infertile with bacterial infections. Infertile males were further classified as teratozoospermic, asthenoteratozoospermic, and oligoasthenoteratozoospermic. HSP70, PKA, MDA, TAC, and GPX (in seminal plasma), PSA, and testosterone (in serum) were analyzed using ELISA while TAC was done using spectrophotometric methods. Microbial culture was done to isolate and identify bacteria in semen. Results obtained were analyzed using GraphPad Prism and SPSS.
 Results: Culture results indicated that 52% of normospermic subjects had no semen infection at the time of the investigation. On the other hand, infertile male subjects without semen infections had 18.7%, while infertile males with semen infections were seen to be 29.2%. Likewise, subjects with bacteriospermia as scanty growth had 12.5%, 9.3% moderate, and 7.3% heavy growth. Significantly higher values of HSP70, PKA, PSA, and MDA were seen in infertile males with bacteriospermia compared with control and infertile males without infection while significantly lower values were seen in TAC, GPX, OPN, and testosterone were observed in the infertile males with bacteriospermia compared with control and infertile males without infection.
 Conclusion: Bacteriospermia significantly increased lipid peroxidation cum oxidative stress leading to altered physiological sperm proteins in the seminal plasma. These alterations could also be responsible for the poor sperm qualities observed in the infertile subjects.

Pattern of Some Sperm Proteins, Anti-oxidants, Testosterone, and Prostate-Specific Antigen of Infertile Males with Sperm Cell Deformities in Port Harcourt, Rivers State

Aim: Infertility is a global problem affecting both males and females. It is a condition with psychological, economic, and medical implications resulting in trauma and stress, particularly in a society where there is a strong emphasis on childbearing. The study therefore aims to investigate the pattern of some sperm proteins, anti-oxidants, and prostate-specific antigen in the seminal plasma of infertile males with sperm cell deformities.
 Study Design: The study is a case-control study designed to investigate semen parameters and sperm proteins in infertile males with sperm cell deformities in Port Harcourt, Rivers State.
 Place and Duration of Study: The study was carried out in the Department of Medical Laboratory Science, Rivers State University, Port Harcourt. However, some of the Laboratory investigations were done in the Chemical Pathology Unit and Medical Microbiology Unit of the University of Port Harcourt Teaching Hospital, Port Harcourt. The Study was between the periods of September 2019 and Feb. 2022.
 Methodology: A total of 276 males indicated interest to participate in the study of which 193 male subjects were recruited. These subjects were grouped into normospermic males (100), azoospermic (40) and oligospermic males (53). Based on their sperm cell morphology and active motility, they were further classified into asthenozoospermic (40), oligoasthenozoospermic (48), teratozoospermic (26), asthenoteratozoospermic (32), and oligoasthenoteratozoospermic (22). HSP70, PKA, MDA, TAC, and GPX (in seminal plasma), PSA, and testosterone (in serum) were analyzed using ELISA while TAC was done using spectrophotometric methods. Results obtained were statistically analyzed using GraphPad Prism and SPSS.
 Results: Sperm motility, TSC, and normal sperm morphology were poor in oligospermic subjects but were very severe in OAT subjects. Sperm proteins were altered in subjects with abnormal sperm cell morphologies. HSP70 and PKA were significantly increased while OPN, TAC, and GPX were significantly decreased in the seminal plasma of infertile males with abnormal sperm cells. Testosterone and PSA in blood plasma were significantly lower and higher respectively.
 Conclusion: Oxidative stress played a significant role in sperm cell deformities and fertility. OAT subjects were the most affected.

Platelet thrombus formation in patients with end-stage renal disease before and after hemodialysis as measured by the total thrombus-formation analysis system

BackgroundPatients with end-stage renal disease (ESRD) receiving hemodialysis (HD) often experience bleeding. However, mechanisms behind this bleeding tendency are incompletely understood but may involve platelet dysfunction. We, therefore, studied platelet-dependent thrombus formation in flowing whole blood inside a microchip coated with collagen, and its association with circulating von Willebrand factor (VWF).MethodsBlood samples were obtained in 22 patients before and after HD. The area under the 10 min flow pressure curve in a microchip (AUC10) reflecting total platelet thrombogenicity was measured, using the Total Thrombus-formation Analysis System (T-TAS01). AUC10 < 260 indicates platelet dysfunction. VWF activity and antigen in plasma were also assayed.ResultsVWF levels were moderately elevated and increased further after HD (P < 0.01 or lower). In contrast, AUC10 before and after HD was < 260 in 17/22 patients and < 130 in 15/22 patients, with no statistically significant difference in pre- vs post-HD measurements, indicating reduced platelet thrombogenicity, but with some variability as 5/22 patients showed normal platelet responsiveness. AUC10 and VWF activity or antigen levels in plasma were not correlated, either before or after HD.ConclusionsMost ESRD patients display moderate-to-severe platelet dysfunction as assessed by shear-induced platelet-dependent thrombus formation with T-TAS01. HD does not influence platelet function despite HD-induced elevations in VWF. T-TAS01 should be further evaluated as a tool in the assessment of bleeding risk in patients on HD.Graphical abstract

Associations between coagulation factor XII, coagulation factor XI, and stability of venous thromboembolism: A case-control study

BACKGROUNDPulmonary embolism (PE) is a fatal clinical syndrome that is generally caused by an embolus from unstable deep venous thrombosis (DVT). However, clinical and biochemical factors that are related to the stability of DVT are not fully understood.AIMTo evaluate the relationships between plasma antigen levels of factor XII (FXII:Ag) and factor XI (FXI:Ag) with the stability of DVT.METHODSPatients with DVT and no PE, DVT and PE, and controls with no DVT or PE that matched for age, gender, and comorbidities were included in this study. FXII:Ag and FXI:Ag in peripheral venous blood were measured using enzyme-linked immunosorbent assays.RESULTSUsing the 95th percentile of FXI:Ag in patients with DVT and PE as the cut-off, a higher FXI:Ag was associated with a higher risk of unstable DVT (odds ratio: 3.15, 95% confidence interval: 1.18-8.43, P = 0.019). Stratified analyses showed consistent results in patients ≤ 60 years (P = 0.020), but not in those > 60 years (P = 0.346).CONCLUSIONHigher plasma FXI:Ag might be a marker for unstable DVT, which might be associated with PE in these patients.

The Role of von Willebrand Factor Antigen in Predicting Survival of Patients with HBV-Related Cirrhosis

Objective The model for end-stage liver disease (MELD) scoring system cannot be used to assess the deterioration of patients with liver cirrhosis caused by infection and portal hypertension. Elevated von Willebrand factor antigen (vWF-Ag) in plasma is associated with portal pressure and complications in patients with liver cirrhosis. We aimed to evaluate whether the addition of vWF-Ag can improve the risk prediction ability of the MELD scoring system. Methods A total of 228 patients with hepatitis B virus (HBV)-related liver cirrhosis were eligible for inclusion in this retrospective study. The vWF-Ag level was assessed by enzyme-linked immunosorbent assay (ELISA). The endpoint of this study was defined as the time to liver transplantation or death. Univariate and multivariate analyses were performed to assess the risk factors associated with transplant-free mortality. Receiver operating characteristic (ROC) curve analysis was used to assess potential discriminatory variables for transplant-free mortality. Results During a median follow-up interval of 30.23 months, 124 patients (54.4%) reached the endpoint of this study. Patients who died or underwent liver transplantation had elevated levels of MELD and vWF-Ag. Moreover, vWF-Ag and MELD showed comparable predictive potential for transplant-free survival (area under the curve [AUC], vWF-Ag = 0.71; AUC, MELD = 0.73). Ultimately, vWF-Ag can significantly improve the predictive potential of MELD in determining transplant-free mortality (AUC, MELD-vWF-Ag = 0.79, P = 0.006). Conclusion An elevated vWF-Ag level was independently associated with transplant-free mortality in patients with liver cirrhosis. The inclusion of vWF-Ag in the MELD scoring system can improve mortality predictions in patients with liver cirrhosis.

Altered Maternal Antibody Profiles in Women With Human Immunodeficiency Virus Drive Changes in Transplacental Antibody Transfer.

Human immunodeficiency virus (HIV)-exposed, uninfected (HEU) children have a higher risk of severe infection, but the causes are poorly understood. Emerging data point to altered antibody transfer in women with HIV (WHIV); however, specific perturbations and the influence of antiretroviral therapy (ART) and HIV viremia remain unclear. We evaluated antigen-specific transplacental antibody transfer across 14 antigens in paired maternal and umbilical cord plasma from 352 Ugandan women; 176 were WHIV taking ART. We measured antigen-specific immunoglobulin G (IgG) sub-class (IgG1, 2, 3, 4) levels and antibody Fcγ receptor (FcγRn, 2a, 2b, 3a, 3b) binding profiles. We used partial least squares discrimi-nant analysis to define antigen-specific transplacental antibody transfer features. Global antibody transfer patterns were similar by maternal HIV serostatus, pointing to effective placental function in WHIV. However, HEU umbilical cord antibody profiles were altered, driven by perturbed WHIV seroprofiles, with higher levels of herpesvirus antibodies (P < .01 for Epstein-Barr virus, herpes simplex virus) and lower levels of classic vaccine-induced antibodies (P < .01 for tetanus, polio, Haemophilus influenzae type b), suggesting that umbilical cord antibody profile differences arise from imbalanced WHIV immunity. Abnormal WHIV antibody profiles were associated with HIV viremia, lower CD4 count, and postconception ART initiation (P = .01). Perturbed immune-dominance profiles in WHIV shift the balance of immunity delivered to neonates. Perturbed HIV-associated maternal antibody profiles are a key determinant of com-promised neonatal immunity. Maternal vaccination interventions may promote transfer of relevant, effective antibodies to protect HEU children against early-life infections.

Measurement of Severe Acute Respiratory Syndrome Coronavirus 2 Antigens in Plasma of Pediatric Patients With Acute Coronavirus Disease 2019 or Multisystem Inflammatory Syndrome in Children Using an Ultrasensitive and Quantitative Immunoassay.

BackgroundDetection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood has high sensitivity in adults with acute coronavirus disease 2019 (COVID-19), but sensitivity in pediatric patients is unclear. Recent data suggest that persistent SARS-CoV-2 spike antigenemia may contribute to multisystem inflammatory syndrome in children (MIS-C). We quantified SARS-CoV-2 nucleocapsid (N) and spike (S) antigens in blood of pediatric patients with either acute COVID-19 or MIS-C using ultrasensitive immunoassays (Meso Scale Discovery).MethodsPlasma was collected from inpatients (<21 years) enrolled across 15 hospitals in 15 US states. Acute COVID-19 patients (n = 36) had a range of disease severity and positive nasopharyngeal SARS-CoV-2 RT-PCR within 24 hours of blood collection. Patients with MIS-C (n = 53) met CDC criteria and tested positive for SARS-CoV-2 (RT-PCR or serology). Controls were patients pre–COVID-19 (n = 67) or within 24 hours of negative RT-PCR (n = 43).ResultsSpecificities of N and S assays were 95–97% and 100%, respectively. In acute COVID-19 patients, N/S plasma assays had 89%/64% sensitivity; sensitivities in patients with concurrent nasopharyngeal swab cycle threshold (Ct) ≤35 were 93%/63%. Antigen concentrations ranged from 1.28–3844 pg/mL (N) and 1.65–1071 pg/mL (S) and correlated with disease severity. In MIS-C, antigens were detected in 3/53 (5.7%) samples (3 N-positive: 1.7, 1.9, 121.1 pg/mL; 1 S-positive: 2.3 pg/mL); the patient with highest N had positive nasopharyngeal RT-PCR (Ct 22.3) concurrent with blood draw.ConclusionsUltrasensitive blood SARS-CoV-2 antigen measurement has high diagnostic yield in children with acute COVID-19. Antigens were undetectable in most MIS-C patients, suggesting that persistent antigenemia is not a common contributor to MIS-C pathogenesis.

Responses to a Neutralizing Monoclonal Antibody for Hospitalized Patients With COVID-19 According to Baseline Antibody and Antigen Levels : A Randomized Controlled Trial.

In a randomized, placebo-controlled, clinical trial, bamlanivimab, a SARS-CoV-2-neutralizing monoclonal antibody, given in combination with remdesivir, did not improve outcomes among hospitalized patients with COVID-19 based on an early futility assessment. To evaluate the a priori hypothesis that bamlanivimab has greater benefit in patients without detectable levels of endogenous neutralizing antibody (nAb) at study entry than in those with antibodies, especially if viral levels are high. Randomized, placebo-controlled trial. (ClinicalTrials.gov: NCT04501978). Multicenter trial. Hospitalized patients with COVID-19 without end-organ failure. Bamlanivimab (7000 mg) or placebo. Antibody, antigen, and viral RNA levels were centrally measured on stored specimens collected at baseline. Patients were followed for 90 days for sustained recovery (defined as discharge to home and remaining home for 14 consecutive days) and a composite safety outcome (death, serious adverse events, organ failure, or serious infections). Among 314 participants (163 receiving bamlanivimab and 151 placebo), the median time to sustained recovery was 19 days and did not differ between the bamlanivimab and placebo groups (subhazard ratio [sHR], 0.99 [95% CI, 0.79 to 1.22]; sHR> 1 favors bamlanivimab). At entry, 50% evidenced production of anti-spike nAbs; 50% had SARS-CoV-2 nucleocapsid plasma antigen levels of at least 1000 ng/L. Among those without and with nAbs at study entry, the sHRs were 1.24 (CI, 0.90 to 1.70) and 0.74 (CI, 0.54 to 1.00), respectively (nominal P for interaction= 0.018). The sHR (bamlanivimab vs. placebo) was also more than 1 for those with plasma antigen or nasal viral RNA levels above median level at entry and was greatest for those without antibodies and with elevated levels of antigen (sHR, 1.48 [CI, 0.99 to 2.23]) or viral RNA (sHR, 1.89 [CI, 1.23 to 2.91]). Hazard ratios for the composite safety outcome (<1 favors bamlanivimab) also differed by serostatus at entry: 0.67 (CI, 0.37 to 1.20) for those without and 1.79 (CI, 0.92 to 3.48) for those with nAbs. Subgroup analysis of a trial prematurely stopped because of futility; small sample size; multiple subgroups analyzed. Efficacy and safety of bamlanivimab may differ depending on whether an endogenous nAb response has been mounted. The limited sample size of the study does not allow firm conclusions based on these findings, and further independent trials are required that assess other types of passive immune therapies in the same patient setting. U.S. government Operation Warp Speed and National Institute of Allergy and Infectious Diseases.

A Rapid Point-of-Care Test for the Serodiagnosis of Hepatitis Delta Virus Infection

Hepatitis Delta virus (HDV) is a satellite of the Hepatitis B virus (HBV) and causes severe liver disease. The estimated prevalence of 15–20 million infected people worldwide may be underestimated as international diagnostic guidelines are not routinely followed. Possible reasons for this include the limited awareness among healthcare providers, the requirement for costly equipment and specialized training, and a lack of access to reliable tests in regions with poor medical infrastructure. In this study, we developed an HDV rapid test for the detection of antibodies against the hepatitis delta antigen (anti-HDV) in serum and plasma. The test is based on a novel recombinant large hepatitis delta antigen that can detect anti-HDV in a concentration-dependent manner with pan-genotypic activity across all known HDV genotypes. We evaluated the performance of this test on a cohort of 474 patient samples and found that it has a sensitivity of 94.6% (314/332) and a specificity of 100% (142/142) when compared to a diagnostic gold-standard ELISA. It also works robustly for a broad range of anti-HDV titers. We anticipate this novel HDV rapid test to be an important tool for epidemiological studies and clinical diagnostics, especially in regions that currently lack access to reliable HDV testing.

SARS-CoV-2 Nucleocapsid Plasma Antigen for Diagnosis and Monitoring of COVID-19.

BackgroundDetection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen in blood has been described, but the diagnostic and prognostic role of antigenemia is not well understood. This study aimed to determine the frequency, duration, and concentration of nucleocapsid antigen in plasma and its association with coronavirus disease 2019 (COVID-19) severity.MethodsWe utilized an ultrasensitive electrochemiluminescence immunoassay targeting SARS-CoV-2 nucleocapsid antigen to evaluate 777 plasma samples from 104 individuals with COVID-19. We compared plasma antigen to respiratory nucleic acid amplification testing (NAAT) in 74 individuals with COVID-19 from samples collected ±1 day of diagnostic respiratory NAAT and in 52 SARS-CoV-2–negative individuals. We used Kruskal–Wallis tests, multivariable logistic regression, and mixed-effects modeling to evaluate whether plasma antigen concentration was associated with disease severity.ResultsPlasma antigen had 91.9% (95% CI 83.2%–97.0%) clinical sensitivity and 94.2% (84.1%–98.8%) clinical specificity. Antigen-negative plasma samples belonged to patients with later respiratory cycle thresholds (Ct) when compared with antigen-positive plasma samples. Median plasma antigen concentration (log10 fg/mL) was 5.4 (interquartile range 3.9–6.0) in outpatients, 6.0 (5.4–6.5) in inpatients, and 6.6 (6.1–7.2) in intensive care unit (ICU) patients. In models adjusted for age, sex, diabetes, and hypertension, plasma antigen concentration at diagnosis was associated with ICU admission [odds ratio 2.8 (95% CI 1.2–6.2), P=.01] but not with non-ICU hospitalization. Rate of antigen decrease was not associated with disease severity.ConclusionsSARS-CoV-2 plasma nucleocapsid antigen exhibited comparable diagnostic performance to upper respiratory NAAT, especially among those with late respiratory Ct. In addition to currently available tools, antigenemia may facilitate patient triage to optimize intensive care utilization.

Von Willebrand factor exerts hepatoprotective effects in acute but not chronic cholestatic liver injury in mice

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system, including elevated levels of the platelet-adhesive protein von Willebrand factor (VWF). Carbon tetrachloride-induced liver fibrosis is reduced in VWF-deficient mice, but it is unclear if VWF plays a pathologic role in all settings of liver fibrosis. Indeed, several studies suggest an anti-fibrotic role for components of the hemostatic system, including platelets, in experimental settings of bile duct fibrosis. However, the role of VWF in this specific pathology has not been examined. We tested the hypothesis that VWF exerts hepatoprotective effects in experimental bile duct injury. Wild-type and VWF-deficient (VWF−/−) mice were challenged with the bile duct toxicant alpha-naphthylisothiocyanate (ANIT) and the impact of VWF deficiency on acute cholestatic liver injury and chronic liver fibrosis was determined. Acute ANIT (60 mg/kg, po)-induced cholestatic liver injury was associated with increased VWF plasma antigen and activity levels. VWF deficiency enhanced ANIT-induced hepatocellular injury, evidenced by increased plasma ALT activity and area of hepatocellular necrosis. Surprisingly, platelet accumulation within necrotic areas was increased in ANIT-challenged VWF−/− mice compared to wild-type mice. Compared to acute ANIT challenge, hepatic platelet accumulation was modest and appeared to be VWF-dependent in mice exposed to ANIT diet (0.05 %) for 6 weeks. However, contrasting the role of VWF after acute ANIT challenge, VWF deficiency did not impact biliary fibrosis induced by chronic ANIT exposure. The results suggest that VWF plays dichotomous roles in experimental acute and chronic ANIT-induced cholestatic liver injury.

Caracterización clínica y epidemiológica de pacientes con enfermedad de von Willebrand que consultan por sangrado uterino anormal atendidas en una institución de alto nivel de complejidad.

Objective: Characterize clinically and epidemiologically patients with von Willebrand disease and abnormal uterine bleeding. Methods: A cross-sectional descriptive observational study was carried out. The study population was women with a diagnosis of von Willebrand’s disease who consulted in a highly complex institution in the city of Medellín. The analysis was carried out through the SPSS V 24 program. Results: 70 patients were included, 50 of these were discarded because they did not present abnormal uterine bleeding or had other diagnoses that could intervene in the characterization as antiphospholipid syndrome. The median age of the included patients was 19.5 years (Min: 11, Max: 52). 9 patients (60%) used contraceptive methods, the reported methods were combined oral contraceptives (26.7%), intrauterine devices (20%) and surgical methods (13.3%). Regarding the clinical characterization, it was found that the most frequent manifestations were the presence of bruises 40% (8) and epistaxis 40% (8). Most of the patients, 65% (13) had not received treatment for abnormal uterine bleeding. Laboratory tests showed the following: hemoglobin 13 g/dL (6.6 - 15.7), hematocrit 37.5% (20.3 - 46.1), platelets 279,000 cells/mm3 (106,000 - 393,000), von Willebrand factor plasma antigen 68.5 IU (19.7 - 205), von Willebrand factor plasma activity 44 IU (23 - 126). Conclusion: Abnormal uterine hemorrhage is a frequent manifestation in women with von Willebrand disease and can present at different stages of life, despite its diagnosis, women do not receive management of this clinical manifestation until their consultation with gynecology. Key words: von Willebrand Diseases, von Willebrand Factor, Abnormal uterine bleeding, Metrorrhagia.

Detection of Borrelia burgdorferi antigens in tissues and plasma during early infection in a mouse model

Borrelia burgdorferi is the causative agent of Lyme borreliosis, which is the most common tick-borne human disease in Europe and North America. Currently, the diagnosis of Lyme borreliosis is based on serological tests allowing indirect detection of anti-Borrelia antibodies produced by patients. Their main drawback is a lack of sensitivity in the early phase of disease and an incapacity to prove an active infection. Direct diagnostic tests are clearly needed. The objectives of this study were to produce tools allowing sensitive detection of potential circulating Borrelia antigens and to evaluate them in a mouse model. We focused on two potential early bacterial makers, the highly variable OspC protein and the conserved protein FlaB. High-affinity monoclonal antibodies were produced and used to establish various immunoassays and western blot detection. A very good limit of detection for OspC as low as 17 pg/mL of sample was achieved with SPIE-IA. In infected mice, we were able to measure OspC in plasma with a mean value of 10 ng/mL at 7 days post-inoculation. This result suggests that OspC could be a good blood marker for diagnosis of Lyme borreliosis and that the tools developed during this study could be very useful.

Multiple diagnostic tests demonstrate an increased risk of canine heartworm disease in northern Queensland, Australia

BackgroundCanine heartworm (Dirofilaria immitis) is a life-threatening infection of dogs with a global distribution. Information on the prevalence of D. immitis and associated risk factors for canine heartworm antigen positivity—and thus disease—in Australia is scarce or outdated. The current reference method for D. immitis diagnosis in dogs is via the detection of heartworm antigen in blood using commercially available microwell-based enzyme-linked immunosorbent assays (ELISAs). Heat treatment of canine plasma prior to testing has been suggested to increase test sensitivity. The aim of the current study was to estimate the prevalence of D. immitis in dogs confined to shelters in Queensland, Australia. The impact of heat treatment on antigen test results was also assessed.MethodsBlood samples (n = 166) were collected directly from dogs in seven shelters across Queensland (latitudinal span of approx. 1700 km) into EDTA blood collection tubes. A commercially available ELISA (DiroCHEK®) was used to detect canine heartworm antigen in untreated and heat-treated plasma. Whole blood was concurrently tested for the presence of microfilariae and D. immitis DNA using a modified Knott’s test and real-time PCR, respectively. Risk factors (age, gender, source, location) associated with the odds of positivity for canine heartworm were assessed using binary logistic regression models.ResultsA total of 16 dogs (9.6%; 95% confidence interval [CI]: 5.9–15.2%) were positive for canine heartworm based on combined test results. Heat treatment did not impact on the positivity of D. immitis antigen within samples (Cohen’s kappa = 0.98), but the optical density was significantly increased in paired plasma samples for D. immitis antigen-positive samples (Wilcoxon matched-pairs signed rank test, two-tailed P < 0.01). Location of the dog in a shelter in northern Queensland was the only risk factor significantly associated with the odds of a dog being more likely to be D. immitis antigen positive (odds ratio: 4.39; 95% CI: 1.26–13.51). All samples positive for the modified Knott’s test were also positive for D. immitis DNA by PCR.ConclusionsThis study demonstrated the presence of heartworm-positive dogs in shelters in Queensland, with positive animals significantly more likely to occur in northern Queensland than southern Queensland. Sustained testing for the presence of D. immitis microfilariae and antigen remain important diagnostic tools in areas with known and re-emerging canine heartworm activity.Graphical

Association of semi-quantitative cryptococcal antigen results in plasma with subclinical cryptococcal meningitis and mortality among patients with advanced HIV disease.

We evaluated two single-step laboratory tests that can quantify the amount of cryptococcal antigen in plasma of patients with advanced HIV disease and could thus gauge the risk of concurrent cryptococcal meningitis and subsequent mortality. These tests are not a substitute for a lumbar puncture.

Clinical utility of antigen carbohydrate 125 for planning the optimal length of stay in acute heart failure

BackgroundThe optimal length of stay (LOS) in patients hospitalized for acute heart failure (AHF) remains controversial. Plasma antigen carbohydrate 125 (CA125) has emerged as a reliable proxy of congestion. We aimed to evaluate whether there is a differential impact of LOS on the risk of 6-month AHF readmission across CA125 levels. MethodsThis is a retrospective study that included 1,387 patients discharged for AHF in two third-level centers. CA125 was measured 48±24 h after admission. The association between CA125 and LOS with the risk of subsequent AHF readmission at 6 months was analyzed by Cox regression analysis accounting for death as a competing event. ResultsThe median (IQR) age of the sample was 78 (69–83) years, 625 (41.1%) patients were women, and 832 (60%) exhibited preserved left ventricular ejection fraction. The median LOS and CA125 were 6 (4–9) days and 36 (17–83) U/mL, respectively. A total of 707 (51%) patients displayed high CA125 levels (≥35 U/mL). At 6 months, 87 deaths (6,3%) and 304 AHF readmissions (21,9%) were registered, respectively. A multivariate analysis revealed a differential effect of LOS on 6-month AHF readmission across CA125 levels (p-value for interaction=0.010). In those with CA125<35 U/mL, LOS≥7 days did not modify the risk (HR:1.31; 95% CI: 0.92-1.87, p=0.131). Conversely, in those with CA125≥35 U/mL, LOS≥7 days was associated with a lower risk of AHF readmission (HR:0.70; 95% CI: 0.51-0.98, p=0.036). ConclusionsIn patients with AHF, high CA125 levels may identify those patients that benefit from a more prolonged hospitalization in terms of reducing the risk of mid-term AHF readmissions.

Seroprevalence and Risk Factors Associated with Human Immunodeficiency Virus Infection Type 1 in Donors of the National Blood Transfusion Center of Libreville (Gabon)

Background: Transmission of HIV through blood transfusion remains a public health problem, particularly in countries in Sub-Saharan Africa. However, no study has determined the epidemiological data regarding HIV-1 infection in Gabonese blood donors. The objective of this study is to assess the seroprevalence of HIV-1 and the risk factors associated with infection in donors from the National Blood Transfusion Center in Libreville (Gabon).&#x0D; Methods: A cross-sectional study carried out from June to August 2020 in 3669 persons donating blood at the National Blood Transfusion Center (NBTC). The ELISA technique (Evolis®, BioRad), the chemiluminescence technique (Cobas® e601, Roche), and the SD Bioline® HIV 1/2 test (Standard Diagnostics. Inc) were used for the detection of anti-HIV-1/2 antibodies and P24 antigen in donor plasma. Data were analyzed using SPSS software version 21.0, with p˂.05 considered statistically significant. &#x0D; Results: The seropositivity rate HIV-1 was 0.8% (30/3669) (95% CI: 0.5; 1.1). The study was composed of 79.4% men and 20.6% women. The most representative age group was of 25-34 years with 54.5%. The seropositivity of men, women, and unrelated voluntary donors was 0.7%, 1.2%, and 1.0%, respectively. The risk factors such as the first blood donation (Adjusted Odds Ratio (AOR) = 0.1 [0.0 ;0.4], P= .002), multiple sexual partners (AOR = 6.2 [2.2;17.2], P= .001), primary educational level (AOR = 10.1 [1.4;75], P = .024), and dental care (AOR = 3.6 [1.2;11], P = .024) were significantly associated with HIV infection. About 0.14% of the patients had co-infection.&#x0D; Conclusion: In the Gabonese context, about one out of a hundred blood donors are HIV-infected. These carriers of HIV infection in the blood banks are mainly new donors with multiple sexual partners, limited education, and poor dental care.