IgG ELISA Test Research Articles

Retrospective Comparison of Two Aspergillus IgG Enzyme Immunoassays for Diagnosing Pulmonary Aspergillosis.

Aspergillus-specific antibodies are diagnostic indicators of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). Tests for detecting Aspergillus-specific antibodies were not used clinically in Japan, and the production of the Aspergillus precipitin test was discontinued. Thus, alternative tests for diagnosing aspergillosis are urgently needed. We retrospectively evaluated 64 patients with suspected ABPA and CPA who underwent precipitin antibody testing. Serum Aspergillus IgG levels were measured and compared using the Bordier Aspergillus fumigatus ELISA and the Platelia Aspergillus IgG (Bio-Rad) kits. Of the participants, 18 were diagnosed with CPA, and 8 were diagnosed with ABPA. Both the Bordier and Bio-Rad kits showed high sensitivity and specificity for CPA and ABPA. The area under the receiver operating characteristic curves for the Bordier and Bio-Rad kits were 0.97 and 0.95, respectively, for CPA, and 0.89 and 0.91, respectively, for ABPA. In contrast to the Bordier kit, the Bio-Rad kit showed relatively low anti-Aspergillus IgG levels and lower sensitivity to non-fumigatus Aspergillus infections. The Aspergillus-specific IgG ELISA tests showed sufficient diagnostic accuracy. Therefore, these assays are recommended as alternatives to the precipitin kit for diagnosing aspergillosis in clinical settings in Japan.

Investigation of Francisella tularensis Seroprevalence and Determination of Risk Factors for Tularemia among Hunters in Northern Cyprus.

Tularemia is a zoonotic disease (reservoir is usually rodents) caused by Francisella tularensis, especially seen in the northern hemisphere. Hunters are in the risk group for this disease. In this study, it was aimed to determine the seroprevalence of tularemia among hunters and determine the risk factors of tularemia in our country. The Turkish Republic of Northern Cyprus (TRNC) is divided into four regions (Nicosia, Kyrenia, Famagusta/Trikomo, and Morphou/Lefka) and 100 volunteer hunters randomly selected from these regions were included in our study. Tube agglutination test (TAT) and F. tularensis IgG and IgM (ELISA method) were applied in all sera. All hunters were filled with a pre-prepared questionnaire to determine risk factors for tularemia. TAT positivity was found in 11%. While F. tularensis ELISA IgG positivity was 17%, IgM positivity was not found in any hunters. Hunters with positive F. tularensis ELISA IgG test (17%) were accepted as seropositive in terms of tularemia. There was no statistically significant difference between the mean age of IgG-positive and negative hunters (p= 0.915). Of the 86 hunters who kept at least one hunting dog in their garden, 15 (17.4%) were IgG-positive. There was no significant relationship between feeding hunting dogs and tularemia (p= 0.561). Our study showed that the seroprevalence of tularemia was high (17%) among hunters, who are considered a risk group, in our country. We think that more epidemiological research should be done on tularemia infection and it should not be overlooked in the clinic.

HUMAN CYSTIC ECHINOCOCCOSIS IN ENDEMIC REGIONS IN BULGARIA - ULTRASOUND SURVEILLANCE, TREATMENT AND FOLLOW-UP OF PATIENTS

Introduction: Cystic echinococcosis (CE) is a chronic disease in humans, usually asymptomatic, but in some cases could be very severe with fatal outcomes. This parasitosis is a health and economic problem in many areas of the world. The actual spread among people with CE in endemic regions is not known. The purpose of prophylactic ultrasound examinations of people in some areas was to clarify the real prevalence of CE and to detect undiagnosed asymptomatic cases and recurrences. Materials and methods: An abdominal ultrasound survey in four endemic regions in Bulgaria with the highest rate of registered patients with CE in Bulgaria for the last five years was conducted. For every patient with CE an epidemiological and clinical history, abdominal ultrasound examination, blood tests and ELISA IgG test for CE were performed. Results: From all 8602 people examined, in seventeen persons (0.2%), liver hydatid cysts were found for the first time. Ssixty five (0.8%) reported a history of previous surgical treatment for CE, of which 54 (83.1%) had passed surgery because of liver CE and 11 (16.9%) had extrahepatic CE (pulmonary, cardiac, bone, spleen). In three (5.6%) patients, who were operated years before for liver CE, recurrences were discovered. In 11 (64.7%) patients devitalized CE4 cysts were observed without any data for previous treatment. Three of the discovered patients with CE were treated with surgery, one with puncture-aspiration-injection-reaspiration, four only with Albendazole. The patients were successfully treated and followed for a period of five years. Conclusions: During the prophylactic ultrasound examinations, a higher percentage of people infected with liver cystic echinococcosis was found compared to the official information. It should be noted that these results are found in areas with the highest incidence of this disease in the country. US screenings give the opportunity for early detection, timely treatment of infected people and to prevent severe complications in patient with CE disease.

Seroprevalence of Brucellosis in Individuals Engaged in Animal Husbandry in Erzurum Region

Objective: Brucellosis is one of the most common zoonotic diseases in our country and the world. This study investigated the seroprevalence of brucellosis in individuals who were engaged in animal husbandry in Erzurum region, were over 18 years of age, or did not have any clinical complaints of brucellosis. Materials and Methods: Our study was conducted on 271 volunteers engaged in livestock farming in 20 districts of Erzurum province between 2020 and 2021. Brucella antibodies were investigated in blood samples using ELISA IgG, ELISA IgM, Rose Bengal, and Standard tube agglutination tests. A questionnaire was administered to the participants to investigate the risk factors of brucellosis. Results: The mean age of the participants was 43.6 ± 15.7.2 years (min:18, max:90), and there were 137 male (50.6%) and 134 female (49.4%) particpants. Seropositivity was detected with ELISA IgG in 40 of 271 participants (14.8%). Seropositivity was detected in the ELISA IgM test in 2 of these 40 participants (0.7%). Seropositivity was found in 46 participants (17%) in the Rose Bengal and 29 individuals in the STA test. According to the serology results, ELISA IgG positivity was higher in male participants compared to female participants (ratio=1.6). Among pet owners, ELISA IgG seropositivity was found higher than the participants who did not have pets (ratio=1.9). In the evaluation based on educational status, the rate of seropositivity was slightly higher in the participants who were illiterate and had a poor level of education. Conclusion: In our study, it was determined that the prevalence rate obtained by ELISA IgG was consistent with previous studies conducted in the region. No significant relationship was observed between the serology results of the participants and their gender and educational status. On the other hand, the positivity of ELISA IgG results was higher among the participants who had pets, and there was a significant relationship at the margin.

Trends in Chlamydia trachomatis IgG seroprevalence in the general population of the Netherlands over 20 years

ObjectivesTo report sex and age-specific Chlamydia trachomatis (Ct) seroprevalence estimates in the general population of the Netherlands between 1996 and 2017 and identify risk factors associated with Ct seropositivity.MethodsParticipants (n=5158,...

Comparison of Native Hydatid Cyst Fluid (HCF), Lyophilized HCF, Antigen B (AgB) and Lyophilized AgB (LAgB) Originated from Echinococcus granulosus Sensu Stricto for Sero-Diagnosis of Active, Transitional and Inactive Human Liver Cystic Echinococcosis.

Cystic echinococcosis (CE) is an important zoonotic parasitic disease caused by the larval stage or metacestode of the tapeworm Echinococcus granulosus sensu lato. Due to treatment protocols for different liver cysts, diagnosis of cyst stages is very important. Different antigens have been used for CE diagnosis. However, each one is more sensitive and effective for the diagnosis of specific CE stages is not known well. We aimed to compare Native Hydatid Cyst Fluid (HCF), Lyophilized Hydatid Cyst Fluid (LHCF), antigen B (AgB) and Lyophilized antigen B (LAgB) originated from E. granulosus sensu stricto (G1-G3) genotype, for sero- diagnosis of active, transitional and inactive human liver CE using ELISA technique. The HCF was collected aseptically from liver CE cysts of sheep slaughtered from 2018 to 2019 in Shiraz slaughterhouse, Southern, Iran. The cysts were characterized by PCR and sequencing for genotype specification. Four types of antigens were used: HCF, LHCF, AgB and LAgB originated from E. granulosus sensu stricto (G1-G3) genotype. Thirty-three serum samples from active, transitional, and inactive human cysts were collected. Overall, 48 samples from other parasitic diseases and 60 samples from healthy subjects as negative controls were checked using four antigens by ELISA method. The best diagnostic sensitivity with 96.97% was observed by anti-LHCF IgG ELISA test. The best specificity with 95.37% was observed in ELISA test using LAgB. Simultaneous test of sera with anti-LHCF IgG ELISA and anti-LAgB IgG ELISA would be the best in the diagnosis of human liver cystic echinococcosis.

Standard definition of a clinical case of mumps and diagnostic effectiveness of the test systems used in the modern period

Introduction. Registration of regular epidemic outbreaks of mumps infection among young people, difficulties in the clinical diagnosis of the disease, the presence of specific clinical manifestations in adults with a severe course of infection make it necessary the improvement of the quality of diagnosis of the disease.
 The aim of the work is to develop a standard definition of a clinical case of mumps and to conduct a comparative assessment of the effectiveness of the diagnostic test systems used for mumps diagnostics based on the determination of their sensitivity and specificity.
 Materials and methods. To develop a standard definition of a clinical case of mumps based on ten combined clinical and laboratory parameters, a mathematical model was built using the logistic regression method. The study included 84 patients with mumps infection (main group) and 66 patients with non-epidemic sialoadenitis (comparison group). For a comparative evaluation of the diagnostic systems VectoParotitis-IgM, VectoParotitis-IgG, ELISA-Mumps-IgM, ELISA-Mumps-IgG, Anti-Mumps Virus ELISA-IgM, and Anti-Mumps Virus ELISA-IgG, a blood serum samples from patients (n = 41) with a diagnosis mumps? were tested in dynamics to assess their sensitivity, specificity, and diagnostic effectiveness.
 Results. The clinical symptom dry mouth increased the chance of diagnosing mumps by 13.7 times, the presence of bilateral lesions of the salivary glands by 6.5 times, the increase in the level of diastase in the urine by 3.2 times. The coefficient of determination R2 was 61.1; the sensitivity was 93% and the specificity 67%; p 0.001. Diagnostic effectiveness of Anti-Mumps Virus ELISA-IgG test system was 84.4%, ELISA-Mumps-IgG 87.2%, and "VectoParotitis-IgG" 88.5%.
 Conclusions. Based on the combination of following clinical symptoms observed simultaneously in patient, of the general weakness, dry mouth, bilateral lesions of the salivary glands, an increase in the level of diastase in the urine, it is possible to establish a clinical diagnosis of mumps with a probability of 81%. The highest diagnostic effectiveness of domestically manufactured test systems for quantitation of IgG antibodies to mumps virus in sick people has been demonstrted.

Evaluation of RUT, and ELISA Tests for Detection of Helicobacter pylori in Dyspeptic Patients Visiting a Tertiary Care Hospital, South India

Helicobacter pylori is main causative agent of acute gastritis and peptic ulcer disease. In certain population, this infection leads to gastric cancers viz., adenocarcinoma, and mucosal-associated lymphoid tissue (MALT) lymphoma. The objective of this study was to comparatively evaluate invasive (RUT) and non-invasive (IgM and IgG ELISA) methods for detection of H. pylori infection among patients visiting a tertiary care hospital. A total of 285 dyspeptic patients undergoing endoscopic examination were included in this study. From each patient one biopsy specimen and serum samples were collected. Biopsy specimen was subjected to RUT and IgM & IgG ELISA tests were performed using serum samples. H. pylori was detected in 127 (44.6%) and 126 (44.2%) cases by RUT and IgM ELISA, respectively. H. pylori were detected in 85 (29.8%) samples by IgG ELISA. Based on the combination of RUT and IgM ELISA test, total 128 (44.9%) patients were positive for H. pylori infection. Most of the positive cases belonged to 21-40 years age group (60 of 128) followed by 41-60 years age group (31 0f 128). All the three diagnostic methods viz., RUT, IgM ELISA and IgG ELISA used in this study showed a greater prevalence of H. pylori infection in female gender compared to male gender. In this study, sensitivity of both RUT and IgM ELISA was similar across different age groups and gender. The advantage of IgM ELISA over RUT is that it does not require endoscopy. Therefore, IgM ELISA could be considered as safe and an alternative method for detection of this pathogen.

Development of a novel diagnostic kit candidate to detect dengue antibody, using IgY and protein a positive Staphylococcus aureus

Early diagnosis of dengue hemorrhagic fever (DHF) is very important in determining further management. Diagnostic kits are intended as relatively faster, easier, and cheaper diagnostic tools. The objectives of this experimental laboratory study was to prepare a diagnostic kit candidate to detect dengue antibody in human serum using co -agglutination methods by utilizing protein A positive Staphylococcus aureus as a carrier to bind Fc immunoglobulin fractions without altering its ability to bind antigen. To enhance the sensitivity and specificity of the diagnostic kit, chicken IgY was used as one of the components. Rabbit immunoglobulin chicken anti-IgY was used as an intermediary connection between protein A positive and Staphylococcus aureus with chicken IgY. Solution A contains Staphylococcus aureus Cowan I and rabbit immunoglobulin chicken anti-IgY serum while Solution B contains anti-dengue chicken serum and dengue antigen. The laboratory experiments produced a formula of A: B = 1~3: 1~3 (v/v), which was then tested to human serum and compared with IgM and IgG ELISA tests as the gold standard. Data on the results of the test were statistically analyzed using chi - square test. Of the 65 qualified samples used, 47.69% resulted in true positive and 41.54% resulted in true negative. Meanwhile, the remaining samples demonstrated false negative (6.15%), positive predictive value (91.2%) and negative predictive value (87.1%). The sensitivity and specificity were 89% and 90%, respectively, with no significant diffe rences (p>0.05). Therefore, co-agglutination method using S. aureus with protein A positive as a carrier can be proposed as a diagnostic kit candidate to detect human serum dengue antibody to screen dengue hemorrhagic fever cases.

Effect of tyrosine kinase inhibitor and conventional chemotherapy on COVID 19 antibody level in hematological patients

Aims: In this study, we aim to discover if there is a difference between COVID 19 antibody level in hematological patients taking conventional chemotherapy and tyrosin kinase inhibitors. Methods: COVİD 19 IgG levels were measured using the QuantiCOR anti-SARS-CoV-2 IgG ELISA test kit on 74 patients who received chemotherapy and used tyrosine kinase inhibitors in the adult hematology clinic of Turgut Özal Medical Center between May 2019 and January 2022. Age, height, weight, badimeks index of the patients were measured, the doses and durations of vaccine use, the time between the first vaccine and the second vaccine, how long after the first vaccine antibodies were checked, and vaccine-related side effects were recorded. Collected data Statistical analysis was performed using Python 3.9 and IBM SPSS Statistics for Windows version 26.0 (New York; USA). Results: Antibody levels of the patients were significantly higher in the healthy control group than in the groups that received chemotherapy and tyrosine kinase inhibitors. Antibody levels of female patients in the control group were higher than male patients. Antibody levels of the patient groups receiving chemotherapy and tyrosine kinase inhibitor were not found to differ between the two groups. When the patients receiving B lymphocyte suppressing chemotherapy in the chemotherapy group were compared with the control group, antibody levels were found to be higher in the control group. Conclusion: COVID 19 vaccination in hematological cancers did not produce adequate antibody response, especially in patients receiving chemotherapy or tyrosine kinase inhibitors.

Seroprevalence of Crimean Congo Hemorrhagic Fever Virus in Livestock, Pakistan

Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is among the deadly human pathogens which cause a highly lethal haemorrhagic fever. CCHFV, a high-priority zoonotic pathogen is distributed widely and is transmitted in a vertical transmission cycle through these animals. Humans get infected by an infected tick bite, contact with viremic livestock blood, and through nosocomial route. Several CCHFV outbreaks have been reported for the past 2 decades in Pakistan and the virus has emerged in previously non-endemic regions as well. It is important to screen animals for CCHFV through an efficient diagnostic assay to prevent the viral zoonotic spill over to humans. Objectives: To screen the presence of CCHFV in sera collected from cattle, goat, and sheep in various regions in Punjab, Khyber Pakhtunkhwa (KP) and Sindh through a pre-established IgG ELISA assay. Methods: A recombinant nucleoprotein (rNP) of CCHFV was used to capture the anti CCFHV IgG antibodies in the animal sera. Results: Among 164 animals tested, 65% (103/164) showed the presence of IgG CCHFV antibodies. From the total 103 animals tested positive, 14.5 % (CI 0-28.2%) were cattle, 63.7% (CI 38.5-60.3%) were goats and 42% (CI 24.4-48.8%) were sheep. Conclusions: High seroprevalence of the CCHFV was expected from these areas as numerous cases of CCHFV have been reported previously. Since no commercial tests are available for the detection of CCHFV-specific antibodies in animals, this IgG ELISA test can be used to screen the animals in areas at risk such as those that have the presence of permissive ticks

Estimate levels of some cytokine in patient infection with Helicobacter pylori

This study includes a collection of 140 samples of blood which have been collected from patient infected with H. pylori ,these samples were collected from AL – Kindy Teaching Hospital in a period from ( November- 2015 to March - 2016 ) with age ranging from 15- 70 years .
 The results showed that from 140 blood samples diagnosis infection with H.pylori by rapid test and make confirmatory for the infection by ELISA technique, make ELISA IgG test technique in this test give 60 patients. Measure the serum level cytokine in the patient infected with H.pylori explain that anti-inflammatory IL-6 chronic phase: (391±5.4 pg/ml )and acute phase : (318.6±7.7 pg/ml) . In the cytokine pro inflammatory TNF-α chronic phase : (391.8±8.6 pg/ml) and acute phase :(290±11.3 pg/ml) and in the proinflammatory MIF cytokine chronic phase : (45.05±2.5 pg/ml) and acute phase : (29.08±2.1 pg/ml)

A Chikungunya Virus Multiepitope Recombinant Protein Expressed from the Binary System Insect Cell/Recombinant Baculovirus Is Useful for Laboratorial Diagnosis of Chikungunya.

Chikungunya virus (CHIKV) is an arbovirus currently distributed worldwide, causing a disease that shares clinical signs and symptoms with other illnesses, such as dengue and Zika and leading to a challenging clinical differential diagnosis. In Brazil, CHIKV emerged in 2014 with the simultaneous introduction of both Asian and East/Central/South African (ECSA) genotypes. Laboratorial diagnosis of CHIKV is mainly performed by molecular and serological assays, with the latter more widely used. Although many commercial kits are available, their costs are still high for many underdeveloped and developing countries where the virus circulates. Here we described the development and evaluation of a multi-epitope recombinant protein-based IgG-ELISA (MULTREC IgG-ELISA) test for the specific detection of anti-CHIKV antibodies in clinical samples, as an alternative approach for laboratorial diagnosis. The MULTREC IgG-ELISA showed 86.36% of sensitivity and 100% of specificity, and no cross-reactivity with other exanthematic diseases was observed. The recombinant protein was expressed from the binary system insect cell/baculovirus using the crystal-forming baculoviral protein polyhedrin as a carrier of the target recombinant protein to facilitate recovery. The crystals were at least 10 times smaller in size and had an amorphous shape when compared to the polyhedrin wild-type crystal. The assay uses a multi-epitope antigen, representing two replicates of 18 amino acid sequences from the E2 region and a sequence of 17 amino acids from the nsP3 region of CHIKV. The recombinant protein was highly expressed, easy to purify and has demonstrated its usefulness in confirming chikungunya exposure, indeed showing a good potential tool for epidemiological surveillance.

Alloreactive memory B cell detection by flow cytometric cross match using polyclonally activated memory B cell culture supernatants

In addition to alloantibodies, alloreactive memory B cell (mBC) evaluation has a potential for immunological risk assessment during transplantation processes. For the alloreactive mBCs evaluation currently, direct Flow Cytometric (FC) analysis using the HLA tetramer staining is an option. Evaluation of alloantibodies produced by the polyclonally stimulated alloreactive mBCs in in vitro culture system seems to be another useful approach, but this needs further downstream applications. In this study, we investigated the usefulness of the Flow Cytometric Cross Match (FCXM-supernatant) in which in vitro polyclonally activated mBCs culture supernatants and potential donor's lymphocytes being used for the mBC detection. FCXM-supernatant assays were performed between culture supernatants of polyclonally activated mBCs obtained from 4 allosensitized multiparous women and 14 renal transplant patients, and their non-alloimmunized spouses' or donors' lymphocytes, and vice versa. HLA typing was performed by SSP method. Anti-HLA antibodies produced by in vitro activated alloreactive mBCs were also evaluated by the Luminex assays. The success of in vitro polyclonal activation of mBCs was evaluated by a total IgG ELISA test and antibody secreting cell analyses by FC. Donor specific alloreactive mBCs were detected by FCXM-supernatant in 45% of the 18 allosensitized cases. Detection rate was 85% (6 out of 7) in the strongly allosensitized cases. No alloreactive mBCs was detected in control cases without allosensitization. FCXM-supernatant negative results of the allosensitized cases were related to low level of allosensitization and insufficient polyclonal stimulation evaluated by total IgG antibody tests of the supernatants. We herein report a practical methodology for alloreactive mBC detection as a donor specific manner using the FCXM-supernatant assay so that this would easily be transformed into a routine test performed in tissue typing laboratories.

Study to assess the prevalence of Herpes Simplex Type 2 (HSV-2) infections in pregnant women in a tertiary care hospital

Aim: Assess the prevalence of Herpes Simplex Type 2 (HSV-2) infections in pregnant women in a tertiary care hospital. Methods: There were a total of one hundred pregnant women that participated in this research. 5 ml blood samples were obtained using vein puncture and placed in a sterile plain tube. These samples were then allowed to clot for 30 minutes before being centrifuged at 3000 rpm for 5 minutes. Each of the resulting serums was placed in a fresh vial, given a label, and kept at a temperature of -20 degrees Celsius until it was time for the ELISA analysis. In order to determine whether or not the serum included HSV-2 IgG antibodies, an HSV-2 specific IgG ELISA test kit was used. Results: In this research, 100 pregnant women were recruited. HSV-2 infection was found in 40% of people. The largest infected group was pregnant women under the age of 25, with 57.14 percent infected, and the lowest in older age groups. Housewives had the greatest prevalence (71.79 percent), followed by private workers (32%), while government employees had the lowest seroprevalence (8.33 percent). The relationship between viral infection and employment was statistically significant (p≤ 0.05).

COVID-19 IgG/IgM patterns, early IL-6 elevation and long-term radiological sequelae in 75 patients hospitalized due to interstitial pneumonia followed up from 3 to 12 months.

BackgroundCOVID-19 pandemic resulted in about 165 million infections and 3.4 million deaths all over the world across 15 months. The most severe clinical presentation of COVID-19 diseases is interstitial pneumonia.MethodsIn this paper we describe clinical outcomes based on radiological features as well as the pattern of haematochemical parameters and IgG/IgM antibodies in 75 patients hospitalized due to COVID-related interstitial pneumonia not requiring intensive care assistance. Each patient underwent routine laboratory tests, including inflammatory markers and coagulation profile at baseline. Computed Tomography (CT) was performed at baseline and after 3 months to assess the persistence of radiological sequelae. A Generalized Linear Model (GLM) was used to test for each patient the association between individual haematochemical parameters at the time of hospital admission and the subsequent radiological features after three months. The presence of IgG antibodies was quantitatively determined in 70 patients at the time of hospital admission and after 3 months. A subgroup of 49 and 21 patients underwent additional dosage of IgG after 6 and 12 months, respectively. IgM serological antibodies were available for 17 patients at baseline and 61 at T3, with additional follow-up for 51 and 20 subjects after 6 and 12 months, respectively.ResultsOnly 28 out of 75 patients discharged from the hospital were totally healed after 3 months, while 47 patients (62.7%) still presented radiological sequelae. According to the GLM model, specific haematochemical baseline parameters—such as IL-6, GPT, platelets and eosinophil count—showed a statistically significant association with the presence of radiological sequelae at month 3 highlighting an OR = 0.5, thus meaning that subjects completely healed after 3 months presented half levels of IL-6 at baseline compared to patients with sequelae. In general, IgG serum levels were always higher than IgM at the time of hospitalization (75% at T0; n = 12 out of 16 patients with data available in both visits), after 3 months (72.1%; n = 44 out of 61 pts.), after 6 months (56.8%; 25 out of 44 pts.), and one year after hospitalization (60%; 12 out of 20 pts.). Overall, IgG and IgM serum levels presented a statistically significant decreasing trend from the baseline to month 3, 6 and 12. One patient presented an increase in IgM between baseline and month 3 but negative PCR test for SARS-COV2 on throat swab.ConclusionsAs supported by our findings on 75 patients, COVID-related interstitial pneumonia triggers early IgG levels (higher than IgM) that gradually decrease over 12 months. Mid-term sequelae are still detectable at lung Computed Tomography after 3 months from the hospital admission. Occasionally, it is possible to observe increase of IgM levels in presence of low concentrations of IgG and negative PCR ELISA tests for SARS-COV2 RNA. Baseline levels of IL-6 could be proposed as predictor of radiological mid/long-term sequelae after COVID-related interstitial pneumonia.

Development and evaluation of a low cost IgG ELISA test based in RBD protein for COVID-19

Serology tests for SARS-CoV-2 have proven to be important tools to fight against the COVID-19 pandemic. These serological tests can be used in low-income and remote areas for patient contact tracing, epidemiologic studies and vaccine efficacy evaluations. In this study, we used a semi-stable mammalian episomal expression system to produce high quantities of the receptor-binding domain-RBD of SARS-CoV-2 in a simple and very economical way. The recombinant antigen was tested in an in-house IgG ELISA for COVID-19 with a panel of human sera. A performance comparison of this serology test with a commercial test based on the full-length spike protein showed 100% of concordance between tests. Thus, this serological test can be an attractive and inexpensive option in scenarios of limited resources to face the COVID-19 pandemic.

Comparison of two rapid test kits with real time polymerase chain reaction for early diagnosis of dengue in Sri Lanka

ABSTRACT Dengue is among the deadliest insect-borne diseases circulating in Sri Lanka. Most of the infections that are diagnosed early are manageable. However, delays in diagnosis may cause fatalities. We evaluated the dengue NS1 antigen card and NS1 SD kit for early diagnosis of dengue using samples from 116 RT-PCR-positive patients admitted within 5 days of the fever onset. RT-PCR tests were performed as standard tests. IgM and IgG ELISA tests were carried out to identify primary and secondary infections. Of the 116 patients who tested positive for dengue using PCR, 48 were positive using NS1 antigen card and 45 were positive using NS1 SD. Patients with 100 copies or higher viral load showed a higher sensitivity in both antigen card and NS1 SD. Of 34 primary infections evaluated, 23 were positive by NS1 antigen card, while the positivity was 21 by NS1 SD. Of the 30 secondary infections evaluated, 15 were positive by NS1 antigen card while 14 by NS1 SD. Our findings showed that while the rapid tests are convenient and much easier to use than PCR, they are less sensitive and need improvement. Until then, clinical diagnosis should have more emphasis on the early diagnosis of dengue.

Second round statewide sentinel-based population survey for estimation of the burden of active infection and anti-SARS-CoV-2 IgG antibodies in the general population of Karnataka, India, during January-February 2021

Demonstrate the feasibility of using the existing sentinel surveillance infrastructure to conduct the second round of the serial cross-sectional sentinel-based population survey. Assess active infection, seroprevalence, and their evolution in the general population across Karnataka. Identify local variations for locally appropriate actions. Additionally, assess the clinical sensitivity of the testing kit used on account of variability of antibody levels in the population. The cross-sectional study of 41,228 participants across 290 healthcare facilities in all 30 districts of Karnataka was done among three groups of participants (low, moderate, and high-risk). The geographical spread was sufficient to capture local variations. Consenting participants were subjected to real-time reverse transcription-polymerase chain reaction (RT-PCR) testing, and antibody (IgG) testing. Clinical sensitivity was assessed by conducting a longitudinal study among participants identified as COVID-19 positive in the first survey round. Overall weighted adjusted seroprevalence of IgG was 15.6% (95% CI: 14.9-16.3), crude IgG prevalence was 15.0% and crude active infection was 0.5%. Statewide infection fatality rate (IFR) was estimated as 0.11%, and COVID-19 burden estimated between 26.1 to 37.7% (at 90% confidence). Further, Cases-to-infections ratio (CIR) varied 3-35 across units and IFR varied 0.04-0.50% across units. Clinical sensitivity of the IgG ELISA test kit was estimated as ≥38.9%. We demonstrated the feasibility and simplicity of sentinel-based population survey in measuring variations in subnational and local data, useful for locally appropriate actions in different locations. The sentinel-based population survey thus helped identify districts that needed better testing, reporting, and clinical management. The state was far from attaining natural immunity during the survey and hence must step up vaccination coverage and enforce public health measures to prevent the spread of COVD-19.

A comparative evaluation of methods for estimating the colostrum quality in sows

ABSTRACT Colostrum is the main source of immunoglobulins (Ig) for neonate piglets and plays a crucial role within the health and growth of the piglet. Currently in pig farming, there are still no widespread practical methods for measuring the Ig concentration in colostrum at herd level. We evaluated sows’ colostrum IgG concentration using an optical and a digital Brix refractometer and their performance was correlated to an IgG ELISA test, and flow cytometry. Colostrum concentrations of IgG and IgA averaged 74.05 ± 21.37mg/mL and 20.2 ± 5.32mg/mL respectively. The mean value of the Brix percentages for optical refractometer was 26.32%, and for digital was 28.32%. The Brix refractometer measurements of colostrum samples presented high correlation for IgG content analyzed by ELISA (Optical = 0.74, Digital = 0.87; P <0.001). Considering the immunophenotyping, the values for IgG and IgA lymphoblasts indicated a highly significant relationship to ELISA (IgG=0.77, IgA=0.84; P<0.001). The Brix refractometer can be considered a useful tool to be included in a colostrum monitoring program to improve potentially neonatal health. In addition, we demonstrated that flow cytometry can be an important tool to analyze and characterize the immunological potential of sow colostrum.