Measuring rheumatoid factor in nonrheumatoid subjects: immunoturbidimetric assay, latex slide test, and enzyme-linked immunosorbent assay compared

1991 ◽  
Vol 37 (10) ◽  
pp. 1766-1769 ◽  
Author(s):  
K Ailus ◽  
L Melamies ◽  
T Tuomi ◽  
T Palosuo ◽  
K Aho
Keyword(s):  
Rheumatoid Arthritis ◽  
Pregnant Women ◽  
Rheumatoid Factor ◽  
Immunosorbent Assay ◽  
Fixation Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Weak Reaction ◽  
Slide Test

Abstract Previous studies of patients with rheumatoid arthritis (RA) have shown a good correlation between results from immunoturbidimetric assays of rheumatoid factor (RF) and latex fixation tests. To extend the research to non-RA subjects, we tested sera from 1000 pregnant women, half each in the first and third trimesters. By turbidimetry, 24 non-RA sera were regarded as positive for RF (greater than or equal to 20 int. units/mL) and 18 sera as borderline (15-19 int. units/mL). By the latex fixation test, 28 non-RA sera gave a clear reaction (positive) and 17 sera a weak reaction (borderline). The association between the tests was statistically highly significant (P less than 0.001). All sera with positive and borderline reactions were tested by enzyme-linked immunosorbent assay for RF isotypes, together with a random subsample of about one-sixth of the original serum samples. Positive RF results by immunoturbidimetry were predominantly due to the presence of IgM-RF. In contrast to some earlier findings, we saw no difference in the prevalence of positive RF reactions between sera from the first and third trimesters.

Evaluation of an IgM-Specific Indirect Enzyme-Linked Immunosorbent Assay for Serodiagnosis of Bovine Respiratory Syncytial Virus Infection: Influence of IgM Rheumatoid Factor on Test Results with Field Sera

1998 ◽  
Vol 10 (4) ◽  
pp. 331-337 ◽  
Author(s):  
D. A. Graham ◽  
K. A. Mawhinney ◽  
M. Elvander ◽  
B. M. Adair ◽  
M. Merza
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rheumatoid Factor ◽  
Immunosorbent Assay ◽  
False Positive ◽  
Bovine Respiratory Syncytial Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Igm Rheumatoid Factor ◽  
Serum Igg ◽  
Syncytial Virus

A commercially available indirect enzyme-linked immunosorbent assay for measuring bovine respiratory syncytial virus (BRSV)-specific IgG was adapted to measure virus-specific IgM. Using this assay, the development of rapid IgM responses in experimentally infected calves was observed 7–9 days postinfection, with peak absorbance values ranging from 1.698 to 2.873. When absorbance values were expressed as a percentage of a positive reference serum, a positive/negative threshold of 22% was determined by testing serum samples from 59 healthy 3–5-month-old calves. Acute and convalescent serum samples collected from 151 calves during 38 outbreaks of respiratory disease were tested, and 130 sera were positive. To determine the number of false-positive results due to the presence of IgM rheumatoid factor, a method for depleting serum IgG by pretreatment of sera with a suspension of protein-G-agarose was developed. All sera that initially tested IgM positive were retested following depletion of serum IgG. False-positive IgM reactions were detected in 23 sera (17.7%). Specific IgM responses were confirmed in 107 sera from 84 calves. Evidence of BRSV infection was detected in 34 of 38 outbreaks. In contrast, seroconversion was detected in 69 calves from 24 outbreaks, confirming the diagnostic potential of the IgM assay. Overall correlation between IgM and seroconversion results was 74.2%. Intra- and interassay reproducibility were 12.50% and 17.48%, respectively (mean coefficients of variation).

scholarly journals Soluble selectins and highly fucosylated ?1-antichymotrypsin in rheumatoid arthritis patients

2015 ◽  
Vol 84 (1) ◽  
pp. 34-40
Author(s):  
Anna Olewicz-Gawlik ◽  
Izabela Korczowska-Łącka ◽  
Paweł Hrycaj
Keyword(s):  
Rheumatoid Arthritis ◽  
Rheumatoid Factor ◽  
Acute Phase Proteins ◽  
Serum Levels ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Controls ◽  
Serum Concentrations ◽  
Serum Samples ◽  
Male And Female ◽  
Leukocyte Extravasation

Introduction. Fucosylation of acute phase proteins and serum soluble selectin levels is increased in rheumatoid arthritis (RA) patients and can influence leukocyte extravasation. Aim. The aim of this study was to evaluate the concentration and fucosylation of ?1-antichymotrypsin (ACT) in relation to serum concentrations of soluble forms of selectins in RA patients. Material and methods. Serum samples of 70 RA patients and 30 healthy controls were examined using sandwich enzyme-linked immunosorbent assay (ELISA). Results. ACT-FR was significantly increased in RA patients when compared to healthy controls (p < 0.001) and significantly correlated with serum concentrations of rheumatoid factor (RF) and antibodies against cyclic citrullinated peptides (ACPA) (p = 0.006, p = 0.04, respectively). Moreover, we found significant correlations between the serum levels of soluble (s)P- and sE-selectin and ACT-FR (p = 0.008 and p = 0.03, respectively) only in male RA patients.Conclusions. Fucosylation of ACT differs between male and female RA patients and is related to sP- and sE-selectin levels only in men.

scholarly journals Characterization of Toxoplasma gondii SAG2 Expressed in Insect Cells by Recombinant Baculovirus and Evaluation of Its Diagnostic Potential in an Enzyme-Linked Immunosorbent Assay

2002 ◽  
Vol 9 (6) ◽  
pp. 1343-1347 ◽  
Author(s):  
Xiaohong Huang ◽  
Xuenan Xuan ◽  
Hiroshi Suzuki ◽  
Chihiro Sugimoto ◽  
Hideyuki Nagasawa ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Immunosorbent Assay ◽  
Insect Cells ◽  
Fluorescent Antibody ◽  
Recombinant Baculovirus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Conformational Structure ◽  
Serum Samples ◽  
Weak Reaction ◽  
Diagnostic Potential

ABSTRACT A baculovirus carrying the SAG2 gene of Toxoplasma gondii was constructed, and recombinant SAG2 protein (S-rSAG2) was expressed in insect cells. S-rSAG2 was recognized by sera from cats and pigs infected with T. gondii. Mice immunized with S-rSAG2 produced high titers of specific immunoglobulin G2a (IgG2a) and IgG1 antibodies. In an indirect fluorescent antibody test, all mouse antisera against S-rSAG2 reacted strongly to the natural parasites, but those against rSAG2 expressed in Escherichia coli (E-rSAG2) only showed very weak reaction, although no markedly difference was found in the reaction to denatured antigen, T. gondii lysate, in Western blot analysis. The results suggest that S-rSAG2 is better than E-rSAG2 in both antigenicity and immunogenicity. Enzyme-linked immunosorbent assay (ELISA) with S-rSAG2 could differentiate clearly between sera from 30 specific-pathogen-free cats and 4 experimentally infected cats. Serum samples from domestic cats in Japan were tested by the ELISA and compared with a latex agglutination test (LAT) and ELISA with E-rSAG2. Of 187 samples, all 35 LAT-positive sera had strong reactions to S-rSAG2 and E-rSAG2. Of the 152 LAT-negative sera, 18 were positive in the ELISA with S-rSAG2, whereas only 2 were positive in the ELISA with E-rSAG2. Although there were significant correlations among the three methods, the ELISA with S-rSAG2 was more sensitive than the others, which could be attributed to the fact that S-rSAG2 shares some common conformational structure with the native antigen. The results suggest that S-rSAG2 would be a useful reagent for the detection of T. gondii infection in cats.

scholarly journals Does Rubella Immunity Predict Measles Immunity? A Serosurvey of Pregnant Women

2006 ◽  
Vol 2006 ◽  
pp. 1-3 ◽  
Author(s):  
Colleen M. Kennedy ◽  
Barbara A. Burns ◽  
Kevin A. Ault
Keyword(s):  
Pregnant Women ◽  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples

Background. This study was undertaken to determine whether rubella immunity infers measles immunity in pregnant women.Methods. Stored serum samples were obtained from the Iowa State Hygienic Laboratory for evaluation of rubella and measles immunities with IgG enzyme-linked immunosorbent assay.Results. Nine hundred serum samples were obtained for testing. The average age of the women at the time of antepartum serum collection was28(range,14to44) years. Measles and rubella immunity were88%and98%, respectively; there was no effect of immunity status by age identified. Eighty eight percent of those with rubella immunity were also measles immune. There was no association between paired rubella and measles immunity identified,P<.0001.Discussion. Known rubella immunity did not infer measles immunity in our population. Thus, we recommend that pregnant women exposed to measles be tested and appropriately treated if they are found to be nonimmune.

scholarly journals POS0441 DEVELOPMENT OF RHEUMATOID ARTHRITIS AMONG ANTI-CITRULLINATED PROTEIN ANTIBODIES POSITIVE ASYMPTOMATIC INDIVIDUALS: A PROSPECTIVE OBSERVATIONAL STUDY

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 449.1-449
Author(s):  
S. Mizuki ◽  
K. Horie ◽  
K. Imabayashi ◽  
K. Mishima ◽  
K. Oryoji
Keyword(s):  
Rheumatoid Arthritis ◽  
Risk Factors ◽  
Observational Study ◽  
Rheumatoid Factor ◽  
Prospective Observational Study ◽  
Enzyme Linked Immunosorbent Assay ◽  
P Value ◽  
Healthy Population ◽  
Asymptomatic Individuals ◽  
Citrullinated Protein

Background:In the idividuals with genetic and enviromental risk factors, immune events at mucosal surfaces occur and may precede systemic autoimmunity. Anti-citrullinated protein antibodies (ACPA) are present in the serum for an average of 3-5 years prior to the onset of rheumatoid arthritis (RA) during an asymptomatic period. In ACPA-positivite individuals, the additional presence of RA-related risk factors appears to add significant power for the development of RA. To date, there have been few reports in which clinical courses of ACPA-positive asymptomatic individuals were investigated prospectively.Objectives:To observe the clinical time course of ACPA-positive healthy population for the development of RA.Methods:Healthy volunteers without joint pain or stiffness, who attended the comprehensive health screening of our hospital, were enrolled in this prospective observational study. The serum ACPA levels were quantified by Ig-G anti-cyclic citrullinated peptide enzyme-linked immunosorbent assay with levels > 4.4 U/mL considered positive. ACPA-positive subjects were followed by rheumatologists of our department clinically or a questionnaire sent by mail for screening to detect arthritis.Results:5,971 healthy individuals without joint symptons were included. Ninty-two (1.5%) were positive for ACPA. Of these, 19 (20.7%) developed RA and two were suspected as RA by mail questionnaire. Their average age were 58-years, and women were 68%. The average duration between the date of serum sampling and diagnosis was 10.7 months. ACPA-positive individuals who developed to RA had higher serum ACPA and Ig-M rheumatoid factor levels than ACPA-positive individuals who did not (P value by Mann-Whitney U test: 0.002, 0.005, respectively).Conclusion:Among ACPA-positive asymptomatic individuals, 20% developed RA. The higher titer of ACPA and Ig-M rheumatoid factor levels are risk factors for devoloping RA.Disclosure of Interests:None declared

scholarly journals Prevalence and clinical correlation of hepatitis E virus antibody in the patients’ serum samples from a tertiary care hospital in Thailand during 2015–2018

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Atiporn Boonyai ◽  
Anchalee Thongput ◽  
Thidarat Sisaeng ◽  
Parisut Phumchan ◽  
Navin Horthongkham ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Tertiary Care ◽  
Laboratory Data ◽  
Organ Transplant ◽  
Hospital Setting ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Care Hospital ◽  
Serum Samples ◽  
Igm Antibodies

Abstract Background Prevalence and incidence of hepatitis caused by HEV infection are usually higher in developing countries. This study demonstrated the HEV seroprevalence and incidence of HEV infection in patients with clinical hepatitis in a tertiary hospital in Thailand. Methods A laboratory-based cross-sectional study was conducted using 1106 serum samples from patients suspected of HEV infection sent to the Serology laboratory, Siriraj Hospital, for detecting HEV antibodies during 2015–2018. Prevalence of anti-HEV IgG and IgM antibodies in general patients, including organ transplant recipients and pregnant women in a hospital setting, were determined using indirect enzyme-linked immunosorbent assay (ELISA) kits. Comparison of laboratory data between groups with different HEV serological statuses was performed. Results HEV IgG antibodies were detected in 40.82% of 904 serum samples, while HEV IgM antibodies were detected in 11.75% of 1081 serum samples. Similar IgG and IgM antibody detection rates were found in pregnant women. Interestingly, anti-HEV IgM antibodies were detected in 38.5% of patients who underwent organ transplantation. Patients who tested positive for anti-HEV IgM antibodies had higher alanine aminotransferase levels than those who had not. In contrast, patients who tested positive for anti-HEV IgG had more elevated levels of total bilirubin than those who tested negative. Conclusions HEV seroprevalence and incidence in patients with clinical hepatitis were relatively high in the Thai population, including the pregnancy and organ transplant subgroups. The results potentially benefit the clinicians in decision-making to investigate HEV antibodies and facilitating proper management for patients.

scholarly journals Prevalence of feline coronavirus antibodies in cats in Bursa province, Turkey, by an enzyme-linked immunosorbent assay

2009 ◽  
Vol 11 (10) ◽  
pp. 881-884 ◽  
Author(s):  
Annamaria Pratelli ◽  
Kadir Yesilbag ◽  
Marcello Siniscalchi ◽  
Ebru Yalçm ◽  
Zeki Yilmaz
Keyword(s):  
Immunosorbent Assay ◽  
Predictive Value ◽  
Gold Standard ◽  
Population Based ◽  
Standard Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
High Association ◽  
Gold Standard Test ◽  
Feline Coronavirus

Feline sera from Bursa province (Turkey) were assayed for coronavirus antibody using an enzyme-linked immunosorbent assay (ELISA). The study was performed on 100 sera collected from cats belonging to catteries or community shelters and to households. The serum samples were initially tested with the virus neutralisation (VN) test and the results were then compared with the ELISA. The VN yielded 79 negative and 21 positive sera but the ELISA confirmed only 74 as negative. The ELISA-negative sera were also found to be free of feline coronoviruses-specific antibodies by Western blotting. Using the VN as the gold standard test, ELISA had a sensitivity of 100% and a specificity of 93.6%, with an overall agreement of 95%. The Kappa (κ) test indicated high association between the two tests (κ=0.86, 95% confidence interval (CI) 0.743–0.980). The positive predictive value (PPV) was 0.8, and the negative predictive value (NPV) was 0.93. The prevalence of FCoV II antibodies in the sampled population based on the gold standard was 62% (95% CI 0.44–0.77) among multi-cat environments, and 4% (95% CI 0.01–0.11) among single cat households.

scholarly journals Development of an Enzyme-Linked Immunosorbent Assay for the Detection of Antibody to Epizootic Hemorrhagic Disease of Deer Virus

2000 ◽  
Vol 12 (2) ◽  
pp. 142-145 ◽  
Author(s):  
James O. Mecham ◽  
Michael M. Jochim
Keyword(s):  
Immunosorbent Assay ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hemorrhagic Disease ◽  
Structural Protein ◽  
Serum Samples ◽  
Epizootic Hemorrhagic Disease ◽  
Diagnostic Potential ◽  
The Us ◽  
Serotype 1 ◽  
Infected Cells

An enzyme-linked immunosorbent assay has been developed to detect antibodies to epizootic hemorrhagic disease of deer virus (EHDV). The assay incorporates a monoclonal antibody to EHDV serotype 2 (EHDV-2) that demonstrates specificity for the viral structural protein, VP7. The assay was evaluated with sequential sera collected from cattle experimentally infected with EHDV serotype 1 (EHDV-1) and EHDV-2, as well as the four serotypes of bluetongue virus (BTV), BTV-10, BTV-11, BTV-13, and BTV-17, that currently circulate in the US. A competitive and a blocking format as well as the use of antigen produced from both EHDV-1-and EHDV-2-infected cells were evaluated. The assay was able to detect specific antibody as early as 7 days after infection and could differentiate animals experimentally infected with EHDV from those experimentally infected with BTV. The diagnostic potential of this assay was demonstrated with field-collected serum samples from cattle, deer, and buffalo.

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