Detection Of IgG Research Articles

Validation of laboratory developed serology assays for detection of IgG antibody to severe acute respiratory syndrome coronavirus 2 in the South African population

Serological assays for detection of IgG, IgM or IgA against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) play an important role in surveillance, antibody persistence, vaccine coverage and infection rate. Serological assays, including both ELISA and rapid lateral flow assays, are available commercially but the cost limits their accessibility for low resource countries. Although serological assays based on mammalian-expressed SARS-CoV-2 spike protein have been previously described these assays need to be validated using samples from local populations within the continent, or country, in which they will be used. Interpretation of results could be influenced by differences in specificity and potential for pre-existing cross-reactive antibodies. In this study, we investigated two laboratory developed serological assays, an enzyme linked immunosorbent assay (ELISA) and an immunofluorescent assay (IFA), developed using recombinant SARS-CoV-2 spike protein, for use in South African populations. The tests were compared with commercially available and South Africa Health Products Regulatory Authority (SAPHRA) approved assays. A panel of 100 residual diagnostic serum samples, collected prior to the pandemic, were tested on three separate occasions to determine a suitable cut-off value for differentiation of positive from negative samples. Specificity of 96 % and 100 % for ELISA and IFA respectively was demonstrated. A total of 82/89 serum samples collected between days 2–94 after onset of illness from patients with a positive molecular result were positive for IgG antibody. The sensitivity of the laboratory developed assays on samples collected > one week after onset of illness was shown to be 100 % and 98.8 % for ELISA and IFA respectively. Positive predictive values were 92.1 % for ELISA and 91.0 % for IFA using characterization of samples as positive based on confirmation of infection using RT-PCR. Serum samples (n = 62) collected from RT-PCR positive patients infected with either ancestral, or emerging variants such as Beta or Delta, tested positive for IgG antibody (62/62) using the laboratory developed assays confirming application of the assays regardless of currently circulating variant during the time of evaluation. High concordance was demonstrated between the laboratory developed assays and the commercial immunoassay among samples collected from South African populations, although the small sample size, especially for the comparison with commercial assays, must be noted. If all quality assurance controls are in place, the use of local laboratory developed assays for high-throughput screening in resource-constrained environments is a realistic alternative option.

Antibodies to the phosphatidylserine/prothrombin complex in the diagnosis of antiphospholipid syndrome

To determine the significance of antibodies to the phosphatidylserine/prothrombin complex (aPS/PT) in patients with systemic lupus erythematosus (SLE) antiphospholipid syndrome (APS). A total of 190 patients were included in the study: 123 (64.7%) with reliable SLE and 55 (29%) with PAPS. The control group included 100 relatively healthy subjects of comparable age. All patients were tested for classical aPL as well as IgG/IgM-anti-PS/PT by enzyme immunoassay. Based on the average values of IgG/IgM aPS/PT of the control group, the levels of positivity were allocated mean (M) + 3 or 5 standard deviations (SD): M+3SD and M+5SD. IgG aPS/PT levels above 73.6 U/ml (M+5SD) were more accurate diagnostic, for IgM aPS/PT above 18.0 U/ml. IgG-aPS/PT were detected in 84 (44%) of 190 patients. Levels above diagnostic levels were detected in 68 (65%) of 104 patients with APS (55 with PAPS and 59 with SLE+APS). Thrombosis was significantly more common in patients with IgG aPS/PT compared with patients negative for IgG aPS/PT. Arterial but not venous thrombosis was associated with IgG aPS/PT positivity. The frequency of detection of IgG aPS/PT in the examined patients was 44%, IgM aPS/PT 29% and their combination 19% of 190 patients. Half of the patients with probable APS had positive IgG aPS/PT and third IgM aPS/PT. Median IgG aPS/PT were significantly higher in patients with APS compared to patients without APS and the control group. Thrombosis was associated with IgG aPS/PT. Arterial thrombosis was significantly more frequently reported in patients with IgG aPS/PT. The sensitivity of IgG aPS/PT for reliable APS at levels greater than 73.6 units/ml was 59%, specificity 92%, for IgM aPS/PT 35% and 91%, respectively.

Rapid and Low-Cost Detection and Quantification of SARS-CoV-2 Antibody Titers of ICU Patients with Respiratory Deterioration Using a Handheld Thermo-Photonic Device.

While research suggests that COVID-19 vaccines are effective in producing anti-SARS-CoV-2 antibodies that reduce the risk of COVID-19 and its potentially severe complications, how long these antibodies persist after the infection/vaccination is unknown. Longitudinal studies and rapid and scalable platforms are needed for large-scale sero-diagnosis and vaccine evaluation. In this study, we examine the efficacy of our recently-developed handheld thermo-photonic device for rapid and low-cost assessment of the adaptive immune response of COVID+ and COVID− patients admitted to the intensive care unit (ICU) at a local hospital due to respiratory deterioration. Antibody testing included detection and quantification of IgG and IgM via thermo-photonic sensing of a commercially available COVID-19 IgG/IgM rapid test as well as standard measurements with quantitative enzyme-linked immunosorbent assays (qELISA). The results demonstrate that the thermo-photonic reader in conjunction with COVID-19 IgG/IgM test cassettes can detect and quantify IgG levels in COVID-19 antibody assays within the clinically relevant range and with a high correlation to those obtained from qELISA. We also found that the IgG antibody is more reliable for detecting individuals with an adaptive immune response to SARS-CoV-2 compared to the IgM antibody. The developed reader offers a low-cost, portable, and scalable solution for accessing the antibody titer of individuals against SARS-CoV-2 and can be used in local hospital settings.

Prevalence and Predictors of Toxoplasma gondii Infection in Psychiatric Inpatients in Fars Province, Southern Iran.

BackgroundPsychiatric patients are at increased risk of exposure to Toxoplasma gondii infection, which may be linked to their living facilities and behaviors. Limited knowledge on the prevalence of T. gondii infection and its associated risk factors in psychiatric patients are available to the international medical communities. Thus, the aim of the current study was to assess seroprevalence of T. gondii and its associated risk factors in psychiatric inpatients in Fars Province, southern Iran.MethodsThis cross-sectional study was carried out on psychiatric patients hospitalized in Ibn Sina Hospital affiliated to Shiraz University of Medical Sciences, Fars Province, southern Iran, March to July 2021. Blood samples were collected from 318 psychiatric patients and assessed for the detection of IgG against T. gondii using enzyme-linked immunosorbent assay (ELISA). Moreover, structured questionnaires were completed for the participants at the time of sampling. Logistic regression analysis was used to assess possible associations between the latent toxoplasmosis and the variables.ResultsThe overall seroprevalence of anti-T. gondii IgG in psychiatric inpatients was 22.3% (71/318; 95% CI = 17.9–27.3). Multivariate analyses revealed that age > 30 years [adjusted odds ratio (AOR) = 2.24, 95% CI = 1.10–4.60, p = 0.03], contact with cats (AOR = 2.52, 95% CI = 1.14–5.58, p = 0.03), raw vegetable consumption (AOR = 3.65, 95% CI = 1.74–7.65, p = 0.001), raw/undercooked meat consumption (AOR = 4.30, 95% CI = 1.47–12.63, p = 0.008), suicide attempt (AOR = 3.77, 95% CI = 1.58–8.97, p = 0.003) and cigarette smoking history (AOR = 0.38, 95% CI = 0.17–0.83, p = 0.02) were independent risk factors for T. gondii infection.ConclusionThe current results demonstrated that contact with cats, raw vegetable consumption and raw/undercooked meat consumption were independent risk factors for T. gondii seropositivity. Moreover, the current study showed significant associations between seropositivity of T. gondii and suicide attempts as well as negative associations between seropositivity of T. gondii and cigarette smoking in psychiatric inpatients using multivariate logistic regression.

Chapter 12a: Epidemiology by country – an overview

TBE is a flavivirus infection of the central nervous system (CNS), transmitted by ticks and in some rare instances by ingestion of unpasteurized milk. It is diagnosed in the forested belts of Northern Eurasia ranging from the UK, eastern France, The Netherlands and Norway down to Italy through central and Eastern Europe, Russia, Kazakhstan, and China to Japan. About 10,000 cases of TBE are reported annually, likely a significant underestimate as serological testing is more sporadic than complete and in some countries and, in some countries, (like Japan) not even available. The European Centre for Disease Prevention and Control (ECDC) have put TBE on their list of notifiable diseases. Their case definition requires clinical symptoms of CNS infection plus virological or serological confirmation of the infection, usually by detection of specific immunoglobulins IgG and IgM. Vaccination against TBE is on the World Health Organization's List of Essential Medicines. the safest and most effective medicines needed in a health system. Surveillance of TBE and the TBEV is incomplete. Reported incidences do not reflect actual risk since this fluctuates annually as a result of changes in exposure, vaccine uptake, intensity of case finding and reporting, climate factors, reservoir animals and ticks - just to mention the most relevant factors. For largely unknown reasons (including human behavior, improved diagnostics, or climate change) TBEV appears to be spreading north, east, west, even south and to higher altitudes to areas that were previously believed to be free of the virus.

Response to COVID-19 booster vaccinations in seronegative people with multiple sclerosis

BackgroundPeople with MS treated with anti-CD20 therapies and fingolimod often have attenuated responses to initial COVID-19 vaccination. However, uncertainties remain about the benefit of a 3rd (booster) COVID-19 vaccine in this group. MethodsPwMS without a detectable IgG response following COVID-19 vaccines 1&2 were invited to participate. Participants provided a dried blood spot +/- venous blood sample 2–12 weeks following COVID-19 vaccine 3. Humoral and T cell responses to SARS-CoV-2 spike protein and nucleocapsid antigen were measured. ResultsOf 81 participants, 79 provided a dried blood spot sample, of whom 38 also provided a whole blood sample; 2 provided only whole blood. Anti-SARS-CoV-2-spike IgG seroconversion post-COVID-19 vaccine 3 occurred in 26/79 (33%) participants; 26/40 (65%) had positive T-cell responses. Overall, 31/40 (78%) demonstrated either humoral or cellular immune response post-COVID-19 vaccine 3. There was no association between laboratory evidence of prior COVID-19 and seroconversion following vaccine 3. ConclusionsApproximately one third of pwMS who were seronegative after initial COVID-19 vaccination seroconverted after booster (third) vaccination, supporting the use of boosters in this group. Almost 8 out of 10 had a measurable immune response following 3rd COVID-19 vaccine.

Seroprevalence of Toxoplasma gondii and associated risk factors in cats from Lima, Peru.

Toxoplasmosis is an important zoonotic disease worldwide caused by the intracellular parasite Toxoplasma gondii. Cats, being hosts, act as a good sentinel for this disease. Thus, the objective of this study was to determine the seroprevalence of T. gondii in cats by examining serum from seven districts of Metropolitan Lima, Peru. We collected and analyzed 303 cat serum samples, and the owners answered a questionnaire about age, gender, lifestyle (indoors only and outdoors access) and feeding (commercial and home food). The samples were tested using indirect hemagglutination (IHA) for detection of antibody IgM and IgG. Among the animals analyzed, we found 52 (17.2%, 95% CI: 13.1% - 21.9%) seropositive cats to T. gondii, of which one corresponded to acute infection (IgM) and 51 to chronic infections (IgG). In addition, the presence of anti-T. gondii antibodies was associated with feeding commercial food and living outdoors access. Our results concluded that T. gondii infections are common in cats with owners in Metropolitan Lima and will be useful to future epidemiological studies.

Evaluation of a Multiplex Bead Assay against Single-Target Assays for Detection of IgG Antibodies to SARS-CoV-2.

ABSTRACTSerological assays for SARS-CoV-2 antibodies must be validated for performance with a large panel of clinical specimens. Most existing assays utilize a single antigen target and may be subject to reduced diagnostic specificity. This study evaluated a multiplex assay that detects antibodies to three SARS-CoV-2 targets. Human serum specimens (n = 323) with known previous SARS-CoV-2 exposure status were tested on a commercially available multiplex bead assay (MBA) measuring IgG to SARS-CoV-2 spike protein receptor-binding domain (RBD), nucleocapsid protein (NP), and RBD/NP fusion antigens. Assay performance was evaluated against reverse transcriptase PCR (RT-PCR) results and also compared with test results for two single-target commercial assays. The MBA had a diagnostic sensitivity of 89.8% and a specificity of 100%, with serum collection at >28 days following COVID-19 symptom onset showing the highest seropositivity rates (sensitivity: 94.7%). The MBA performed comparably to single-target assays with the ability to detect IgG against specific antigen targets, with 19 (5.9%) discrepant specimens compared to the NP IgG assay and 12 (3.7%) compared to the S1 RBD IgG assay (kappa coefficients 0.92 and 0.88 compared to NP IgG and S1 RBD IgG assays, respectively. These findings highlight inherent advantages of using a SARS-CoV-2 serological test with multiple antigen targets; specifically, the ability to detect IgG against RBD and NP antigens simultaneously. In particular, the 100.0% diagnostic specificity exhibited by the MBA in this study is important for its implementation in populations with low SARS-CoV-2 seroprevalence or where background antibody reactivity to SARS-CoV-2 antigens has been detected.IMPORTANCE Reporting of SARS-CoV-2 infections through nucleic acid or antigen based diagnostic tests severely underestimates the true burden of exposure in a population. Serological data assaying for antibodies against SARS-CoV-2 antigens offers an alternative source of data to estimate population exposure, but most current immunoassays only include a single target for antibody detection. This report outlines a direct comparison of a multiplex bead assay to two other commercial single-target assays in their ability to detect IgG against SARS-CoV-2 antigens. Against a well-defined panel of 323 serum specimens, diagnostic sensitivity and specificity were very high for the multiplex assay, with strong agreement in IgG detection for single targets compared to the single-target assays. Collection of more data for individual- and population-level seroprofiles allows further investigation into more accurate exposure estimates and research into the determinants of infection and convalescent responses.

Immunogenicity and safety of an inactivated SARS-CoV-2 vaccine in people living with HIV: A cross-sectional study.

We aimed to analyze the efficacy and safety of an inactivated SARS‐CoV‐2 vaccine in people living with HIV (PLWH). A total of 143 PLWH and 50 healthy individuals were included in this study. A commercially available magnetic chemiluminescence enzyme immunoassay kit was used to detect serum IgG and IgM antibodies against SARS‐CoV‐2. Serum levels of SARS‐CoV‐2‐specific IgG were significantly higher in the control group than in the PLWH group (p = 0.001). Overall, 76% of individuals in the control group were detected with seropositivity IgG against SARS‐CoV‐2 compared to 58% in the PLWH group (p = 0.024). In PLWH with IgG seropositivity, CD4+ T‐cell counts before antiretroviral therapy (ART) was higher (p = 0.015). Multivariable analysis indicated that CD4+ T cells at IgG detection (odds ratio [OR] = 1.004, p = 0.006) and time after vaccination (OR = 0.977, p = 0.014) were independently associated with seropositivity IgG against SARS‐CoV‐2 in PLWH. Neutralizing antibody (nAb) titers in PLWH against wild‐type SARS‐CoV‐2 were similar to those in the control group (p = 0.160). The proportion of seropositive nAbs against wild‐type SARS‐CoV‐2 was also similar (95% in the control group vs. 97% in the PLWH group, p = 0.665). Similar results were obtained when nAb was detected against the delta variants with similar titers (p = 0.355) and a similar proportion of seropositive nAbs were observed (p = 0.588). All the side effects observed in our study were mild and self‐limiting. The inactivated COVID‐19 vaccine appears to be safe with good immunogenicity in Chinese PLWH.

Performance of a rapid immuno-chromatographic test (Schistosoma ICT IgG-IgM) for detecting Schistosoma-specific antibodies in sera of endemic and non-endemic populations

BackgroundSchistosomiasis, an acute and chronic parasitic disease caused by human pathogenic Schistosoma species, is a neglected tropical disease affecting more than 220 million people worldwide.For diagnosis of schistosomiasis, stool and urine microscopy for egg detection is still the recommended method, however sensitivity of these methods is limited. Therefore, other methods like molecular detection of DNA in stool, detection of circulating cathodic antigen in urine or circulating anodic antigen in urine and serum, as well as serological tests have gained more attention. This study examines the sensitivity and specificity of a rapid diagnostic test based on immunochromatography (Schistosoma ICT IgG-IgM, LD Bio, Lyon, France) for simultaneous detection of specific IgG and IgM antibodies in serum, against Schistosoma spp. in endemic and non-endemic populations.Methodology/Principal findingsFrozen banked serum samples from patients with confirmed schistosomiasis, patients with other helminth infections, patients with seropositive rheumatoid arthritis and healthy blood donors were used to assess the sensitivity and the specificity of the Schistosoma ICT IgG-IgM rapid diagnostic test.The test showed a sensitivity of 100% in patients with parasitologically confirmed schistosomiasis, irrespective of the species (S. mansoni, S. haematobium, S. japonicum, S. mekongi). In healthy blood donors and patients with rheumatoid factor positive rheumatoid arthritis from Europe, specificity was 100%. However, in serum samples of patients with other tissue invasive helminth infections, the test showed some cross-reactivity, resulting in a specificity of 85%.Conclusion/SignificanceWith its high sensitivity, the Schistosoma ICT IgG-IgM rapid diagnostic test is a suitable screening test for detection of Schistosoma specific antibodies, including S. mekongi. However, in populations with a high prevalence of co-infection with other tissue invasive helminths, positive results should be confirmed with other diagnostic assays due to the test’s imperfect specificity.

High prevalence of SARS-Coronavirus-2 in patients with inflammatory bowel disease and the role of soluble angiotensin converting Enzyme2

Context: Patients with inflammatory bowel disease (IBD) were found to have the higher intestinal expression of Angiotensin-Converting Enzyme2 (ACE2) that could consequently increase susceptibility to COVID-19 infection. Objective: This study reports the outcomes of COVID-19 infection in a large cohort of IBD patients. We compare levels of serum ACE and IFN-α between COVID19 patients with and without IBD. We performed a cross-sectional retrospective multicenter study. Methods: We enrolled patients with IBD screened for SARS-COV-2 in six medical centres in Iran from June to November 2020. The blood samples were drawn to measure COVID-19 IgM and IgG, and serum levels of sACE2, sACE1, and interferon-α, regardless of suspicious symptoms have done the molecular test. Results: A total of 534 IBD patients were included in the study. Of these, 109 (20.0%) cases had detectable IgG and IgM against SARS-CoV-2. sACE2 levels were higher in IBD patients than controls, whereas ACE1and IFN-α levels were similar among groups.

Serological evidence of the circulation of the Rift Valley fever virus in sheep and goats slaughtered in Yaoundé, Cameroon.

BackgroundRift Valley fever (RVF) is an emerging mosquito‐borne haemorrhagic fever disease capable of causing severe outbreaks with high mortality and morbidity in human, livestock, and wildlife species, particularly in Africa. The onset of the disease in humans is often preceded by epizootic circulation in animals. Therefore, this study was conducted to investigate the seroprevalence of Rift Valley fever virus (RVFV) infection in animals slaughtered in the “Marché huitième” slaughterhouse in Yaoundé, Cameroon.MethodsA cross‐sectional study was conducted at the “Marché huitième” slaughterhouse in Yaoundé, Centre region of Cameroon in March 2020. Blood samples of two species of small ruminants (sheep and goat) were collected and processed. Serum was analysed for detection of RVFV IgG and IgM using commercial ELISA tests.ResultsOf the 191 ruminants tested, RVFV IgG antibodies were positive in 10 (5.2%). Regarding categorization of the population based on the species and gender, sheep and female animal had the highest seroprevalence of 6.4% (3/47) and 7.0% (8/115), respectively. All sera from IgG antibodies‐positive samples were negative to IgM antibodies.ConclusionThis study provides evidence of the circulation of RVFV in small ruminants sold and slaughtered at the “Marché huitième” slaughterhouse in Yaoundé and highlights the need to develop a surveillance system for this virus encompassing humans, livestock, wildlife, and vectors in Cameroon.

Prevalence of hepatitis B and D viruses in HIV-infected persons in the Socialist Republic of Vietnam

The aim of this study was to estimate the prevalence of hepatitis B and D viruses among HIV-infected residents of South Vietnam.Materials and methods. The study material was represented by 316 blood serum samples collected from HIV-infected residents of the Socialist Republic of Vietnam taking antiretroviral therapy. The subjects were examined for the presence of HBV markers with a qualitative detection of HBsAg, HBs IgG, HBcore IgG, anti-HDV, DNA HBV, and RNA HDV. HBV and HDV complete genomes nucleotide sequences were obtained for 23 samples from HIV+HBV+HDV co-infected patients. Amplification and subsequent sequencing of HBV and HDV were performed using nested PCR with pair’s overlapping primers jointly flanking the complete HBV and HDV genomes, respectively.Results. Serological markers of HBV and HDV were presented in the following ratios: HBsAg — 9.17%, anti-HBs Ig G — 10.44%, anti-HBcore Ig G — 42.08%, total anti-HDV — 9.81%. HBV DNA was detected in 32.58% of cases, including 23.41% of HBsAg-negative individuals. HDV RNA was detected in 24.13% of HBsAg-positive individuals and 21.62% of HBsAg-negative, which amounted to 22.33% of HBV-positive individuals and 7.27% of the total group, respectively. In phylogenetic analysis, HBV subgenotype B4 (60.89%) prevailed among HIV-infected patients compared to C1 (21.73%), B2 (8.7%), C2 (4.34%) and C5 (4.34%). Phylogenetic analysis of HDV nucleotide sequences showed the prevalence of HDV genotype 1 (78.26%) compared to genotype 2 (21.74%). The hepatitis Delta virus prevalence in patients with HIV+HBV coinfection, and the prevalence of seronegative HDV in patients with OBI indicate the need to use PCR in hepatitis highly endemic regions for hepatitis B and hepatitis D screening of the general population and especially those at-risk groups.

Immune surveillance for six vaccinable pathogens using paired plasma and dried blood spots in HIV infected and uninfected children in Kinshasa

Child vaccination reduces infant mortality rates. HIV-infected children present higher risk of diseases than non-infected. We report the protection coverage rates for 6 vaccine-preventable diseases in a paediatric population from the Democratic Republic of the Congo (DRC) and the impact of HIV infection, providing the first data on the validity of dried blood samples (DBS) to monitor the immune protection. During 2016–2018 DBS from 143 children/adolescents were collected in Kinshasa (DRC), being 52 HIV-infected. Forty-two had a paired plasma sample. Protective IgG was quantified (VirClia-IgG,VIRCELL) to obtain the optimal cut-off in IgG detection in DBS. ROC curves were generated with R software and statistical analyses with Stata. Protective IgG levels varied across pathogens, not reaching herd immunity. HIV-infected presented lower vaccine protection than uninfected for all analyzed pathogens, except rubella, with statistically significant differences for measles (30.8% vs. 53.8%; p = 0.008) and tetanus (3.8% vs. 22%; p = 0.0034). New cut-offs were calculated when using DBS to improve test performance. We reinforce the necessity to increase pediatric vaccination coverage in Kinshasa, especially in HIV seropositive, with less capacity to maintain adequate antibody levels. DBS were useful to monitor vaccination coverage in seroprevalence studies in resource-limited settings, after optimizing the cut-off value for each pathogen.

Prevalence of antibodies to the hepatitis E virus in the population of the Republic of Belarus

Rationale. Hepatitis E (HE) is a zooanthroponosis. Domestic pigs are the main reservoir for hepatitis E virus (HEV) in the Republic of Belarus (RB). Considering the well-developed pig farming, there is a high risk of infection spread among the population; however, the scale of virus circulation and patterns of HE epidemiology in the above region are still insufficiently explored.The aim of the study is to assess HEV seroprevalence specific for the HE epidemic process in RB.Materials and methods. Serum samples (n = 2,784) collected from patients of infectious disease departments at hospitals (n = 1,669) and relatively healthy people (n = 1,114) from different RB regions were used to measure the activity of alanine aminotransferase (ALT) by a kinetic rate method as well as IgG antibodies to HEV by the enzyme-linked immunosorbent assay (ELISA).Results. In the group of healthy people, anti-HEV IgG were detected in 7.3% (95% CI, 5.8–9.0). In the group of patients with liver disorders, the detection frequency was significantly higher, reaching 11.2% (95% CI, 9.6–12.9). In the groups of healthy people and patients with elevated ALT levels, the HEV seroprevalence did not depend on their gender or the region of residence. The anti-HEV IgG detection frequency gradually increased among olderage patients and reached the peak levels (15.9% on average) in the over-64 age group.Conclusions. RB is characterized by intensive HEV circulation, while the HE epidemic process is characterized by a latent nature. The actual prevalence of HЕ seromarkers among the RB population exceeds the frequency of diagnosed cases, suggesting insufficient vigilance of healthcare workers towards HE and subclinical forms of infection in most of the patients.

Immune complexes as a tool for strongyloidiasis immunodiagnosis in kidney and liver transplant candidate.

Strongyloidiasis is a chronic and asymptomatic infection in immunocompetent patients. Immunocompromised patients, such as organ transplant candidates, can develop severe forms of this disease, and the best way to prevent progression to these forms is early diagnosis. Serological techniques using specific IgG and immune complexes (IC) detection can help in the diagnosis of these patients. This study aimed to detect specific anti-Strongyloides IC and IgG antibodies in kidney transplant (KT) and liver transplant (LT) candidates. A total of 100 blood samples was collected from transplant candidates (50 blood samples each from KT and LT candidates). Serum was obtained and analysed using enzyme-linked immunosorbent assay for IC and IgG detections. The IC levels showed frequencies of 18% and 2% in the KT and LT groups, respectively, whereas anti-Strongyloides IgG was detected in 34% and 12% of KT and LT candidates, respectively. The correlation between IC and IgG detection is poor in KT candidates, while in LT candidates, there is a significant positive correlation. The detection of IC can be an additional tool for the diagnosis of strongyloidiasis, especially when associated with the detection of specific IgG anti-Strongyloides antibodies.

A molecularly imprinted electrochemical sensor with tunable electrosynthesized Cu-MOFs modification for ultrasensitive detection of human IgG

Human IgG is one of the most important immunoglobulins in the human body. The present study described the fabrication of four kinds of layer-by-layer structures of copper metal-organic frameworks (Cu-MOFs) on the working electrode by electrodeposition, which were then applied as an electrochemical sensor for the sensitive determination of IgG in serum. First, MOFs synthesized using different deposition potentials are expected to have varied morphology and properties. Herein, four copper MOFs (Cu-MOFs) were electrosynthesized by a simple and direct reduction approach. The as-synthesized Cu-MOFs exhibit varied morphology and electrocatalytic behavior. Then, IgG was employed as a template in the electropolymerization of pyrrole-imprinted films on the surface of glassy carbon electrodes. Finally, the template protein was removed to form a molecularly imprinted film with the capability to qualitatively and quantitatively signaling of IgG. Under optimized conditions, the sensor for IgG exhibits a wide detection range of 0.01–10 ng mL−1 with a limit of detection (LOD) of 3 pg mL−1 (S/N = 3). Besides, other parameters including the selectivity, reproducibility (RSD 3.6%), and recovery rate (95.2–102.0%) are all satisfactory. The practicability of the sensor was verified by detecting IgG in human serum samples, which indicated that the sensor was suitable for potential clinical applications.

Molecular Evaluation of Human Parvovirus B19 Infection and Associated Risk Factors among Pregnant Women in Bushehr Province, Southern Iran.

Given the importance of human parvovirus B19 infection during pregnancy and the potential risks to the fetus, this study was designed to determine the prevalence, genotypic pattern, and risk factors of parvovirus B19 infection among a population-based sample of pregnant women in Bushehr Province, southern Iran. A total of 824 pregnant women were enrolled in this study. Serum samples were screened for the detection of anti-parvovirus B19 IgM and IgG by ELISA. The molecular evaluation was performed by nested polymerase chain reaction, targeting the non-structural protein 1-viral protein 1 unique region of the genome, and sequencing. Of 824 pregnant women, 330 (40.1%) were positive for anti-parvovirus B19 IgG and 50 women (6.1%) had anti-parvovirus B19 IgM. A greater rate of anti-parvovirus B19 IgG seroprevalence was observed in women older than 39 years, in Afghan immigrants, and in those women with more parities. Anti-parvovirus B19 IgM seroprevalence decreased with increasing gestational age and was significantly greater among women in the first trimester of pregnancy and among residents of the city of Borazjan. Moreover, 0.73% of the pregnant women had parvovirus B19 viremia with genotype 1 and subtype 1a. Parvovirus B19 DNA was detected in the samples collected in late autumn and winter, which is a rainy season associated with temperate climes in southern Iran. According to the results of this study, approximately 60% of pregnant women in this region are serologically negative and susceptible to parvovirus B19 infection. Therefore, assessment for maternal parvovirus B19 infection is important and should be considered as part of the fetal-maternal health policy in Iran.

Helminth Infections in Children.

Helminth Infections in Children.

Antibody response to the COVID-19 ChAdOx1nCov-19 and BNT162b vaccines after temporary suspension of DMARD therapy in immune-mediated inflammatory disease (RESCUE).

ObjectiveTo assess the antibody response to disease-modifying antirheumatic drug (DMARD) therapy after the first and second dose of the ChAdOx1nCov-19 (AstraZeneca (AZ)) and BNT162b (Pfizer) vaccines in patients with immune-mediated inflammatory disease (IMID) compared with controls and if withholding therapy following the first vaccination dose has any effect on seroconversion and SARS-CoV-2 antibody (Ab) levels.MethodsA multicentre three-arm randomised controlled trial compared the immunogenicity of the Pfizer and AZ vaccines in adult patients on conventional synthetic (csDMARD), biologic (bDMARD) or targeted synthetic (tsDMARD) therapy for IMID (n=181) with a control group (n=59). Patients were randomised to continue or withhold DMARD therapy for 1–2 weeks post first dose vaccination only. Serum SARS-CoV-2 IgG detection (IgG ≥1.0 U/mL) and titres against the S1/S2 proteins were measured at baseline, 3–4 weeks post first vaccination and 4 weeks post second vaccination.ResultsAZ vaccination was given to 47.5%, 41.5% and 52.5% in the continue, withhold and control groups, respectively while Pfizer vaccination was given to 52.5%, 58.5% and 47.5% among the continue, withhold and control groups, respectively. Seroconversion rates following the first dose in the AZ and Pfizer groups were only 27.3% vs 79.2% (p=0.000) and 64.58% vs 100% (p=0.000), respectively in the IMID groups who continued therapy compared with the AZ and Pfizer controls, respectively. Withholding DMARD therapy following the first vaccination dose resulted in higher seroconversion to 67.7% and 84.1% in the AZ and Pfizer groups, respectively. Following the second AZ and Pfizer vaccinations when all DMARDs were continued, despite a slightly lower seroconversion rate (83.7% vs 100%, p=0.000 and 95.9% vs 100%, p=0.413), respectively, the mean SARS-CoV2 IgG Ab titres were not significantly different in the csDMARD and bDMARD groups compared with the controls regardless of hold while it was significantly lower in patients taking tsDMARD (12.88 vs 79.49 U/mL, p=0.000).ConclusionsFollowing the first vaccination dose, antibody responses were lower in IMID on DMARD therapy, however the final responses were excellent regardless of hold with the exception of the tsDMARD group where withholding therapy is recommended. At least 2 vaccinations are therefore recommended preferably with an messenger RNA vaccine.Trial registration numberANZCTR: 12621000661875.