scholarly journals Value of immunoglobulin G avidity for primary cytomegalovirus diagnosis in pregnant women compared to nested polymerase chain reaction

2016 ◽  
Vol 31 (2) ◽  
Author(s):  
Maysaa El Sayed Zaki ◽  
Walaa Othman El Shabrawy
Keyword(s):  
Pregnant Women ◽  
Antibody Test ◽  
First Trimester ◽  
High Avidity ◽  
Nested Polymerase Chain Reaction ◽  
Recent Infection ◽  
Igg Avidity ◽  
Avidity Test ◽  
Egyptian Women ◽  
Pcr Method

Primary human cytomegalovirus (HCMV) infection in pregnancy especially in the first term carries high risks to foetus. Diagnosis depends mainly on laboratory tools as clinical diagnosis is non specific. The aim of the present study was to detect recent infection with HCMV in cohort pregnant Egyptian women in the first trimester by serological detection of specific IgM, IgG and IgG avidity test compared to nested PCR method. This study was performed on consecutive pregnant women. Blood samples were obtained and sera were separated from 120 pregnant women in their first trimester of pregnancy and were screened for anti-CMV IgG, IgM and IgG avidity by ELISA and for HCMV-DNA by PCR. Positive IgG for HCMV was 62.5% and positive IgM was 15%. IgG avidity results showed that low, intermediate and high avidity represented 33.3%, 16.7% and 50%, respectively of IgM positive patients and 42.1%, 38.6% and 19.3%, respectively of IgM negative patients. Detection of HCMV DNA by PCR was positive in one of 24 IgM negative/low IgG avidity, in three of 22 IgM negative/intermediate IgG avidity and in all IgM positive/low IgG avidity patients. Confirmatory testing for primary infection with the combined use of IgG avidity with IgM antibody test in pregnant women during the first trimester is an accurate screening tool. The use of PCR as a diagnostic method can be applied to pregnant women with IgM antibodies and low IgG avidity results or in presence of isolated low or intermediate avidity IgG.

scholarly journals Evaluation of the TGS TA system for the detection of anti-Toxoplasma antibodies

2017 ◽  
Vol 32 (1) ◽  
Author(s):  
Olivia Arpino ◽  
Annalisa Cianflone ◽  
Maria Teresa Manco ◽  
Alessia Paganini ◽  
Massimo De Paschale ◽  
...  
Keyword(s):  
High Avidity ◽  
Past Infection ◽  
Recent Infection ◽  
Igm Antibodies ◽  
Igg Avidity ◽  
Avidity Test ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

<em>Background and aims.</em> The aim of the present study was to evaluate the new chemiluminescence TGS TA system of Technogenetics (Milan, Italy) for detecting anti-Toxoplasma IgG and IgM antibodies and IgG avidity. The TGS TA system was compared with our chemiluminescence routinely used system, LIAISON XL, supplied by Diasorin (Saluggia, Italy), for the detection of IgG and IgM antibodies. Only in positive IgM samples (retrospective study) and for the IgG avidity (if existent), TGS TA system was compared to an Enzyme Linked Fluorescent Assay (ELFA) test (VIDAS, BioMérieux, Marcy-l’Étoile, France). <br /><em>Materials and methods</em>. Three hundred and one sera samples, from women who came to our centre for the routine follow up pregnancy, were examined with the TGS TA system and divided in 3 groups according to IgG and IgM screening LIAISON XL tests: 106 were non-immune women (Group 1), 100 were pregnant with past infection (Group 2) and 95 were pregnant with positive or equivocal IgM (82 with positive IgG and 13 with negative IgG) (Group 3). <br /><em>Results</em>. The overall concordance of the IgG results between LIAISON XL and TGS TA was 99.3%: 100% in Group 1, 98% in Group 2 and 100% in Group 3. The overall concordance of the IgM results between LIAISON XL and TGS TA was 93.9%: 100% in Group 1, 94% in Group 2 and 82.8% in Group 3. In Group 3, the concordance between the results of the IgG avidity with the ELFA and TGS TA tests was 81.7%. Comparing the clinical diagnosis obtained with our protocol and that of the TGS TA system, the overall concordance was 92.7%: 100% in Group 1, 92.0% in Group 2 and 78.9% in Group 3. <br /><em>Conclusions</em>. The overall concordance of IgG antibodies is excellent for both protocols while for IgM antibodies is very high in the first group and lower in the third group, due to the presence of non-specific IgM subjects in this group. The TGS TA avidity test seems to predict ealier the maturation of the IgG compared to the ELFA test since many samples with low avidity with the ELFA were seen with moderate avidity with TGS TA and all those with borderline avidity with the ELFA were seen with high avidity with TGS TA. This system shows to be a valuable tool with overall good clinical correlation and able to clearly identify nonspecific subjects, those with a non-recent infection.

scholarly journals Toxoplasmosis and pregnancy: Perinatal results and association of the IgG avidity test with congenital infection in pregnant women with positive anti-Toxoplasma gondii IgM [Abstract in English]

2010 ◽  
Vol 20 (1) ◽  
pp. 45
Author(s):  
Virgílio Gonçalves de Souza-Júnior ◽  
Ernesto Antonio Figueiró-Filho ◽  
Danilo De Cerqueira Borges ◽  
Vanessa Marcon Oliveira ◽  
Lílian Rezende Coelho
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Predictive Value ◽  
Congenital Infection ◽  
Neonatal Infection ◽  
High Avidity ◽  
Igg Avidity ◽  
Risk Pregnancy ◽  
Avidity Test ◽  
Acute Toxoplasmosis

AIMS: To verify the perinatal outcomes in pregnant women with acute toxoplasmosis, and to determine if there was association between the results of Toxoplasma gondii-specific IgG avidity test and the presence or absence of fetal/neonatal infection. METHODS: A cross-sectional study included pregnant women with serological diagnosis of acute toxoplasmosis (presenting a positive Toxoplasma gondii-specific IgM test) attended at the outpatient unit for high-risk pregnancy of the Faculty of Medicine, Federal University of Mato Grosso do Sul, Brazil, in the period from November 2002 to November 2007. Test results demonstrating IgG avidity index above 30% were considered high avidity, while values below 30% were considered low avidity. Fetal and/or neonatal infection was defined by positive result for the polymerase chain reaction in amniotic fluid, or by a positive Toxoplasma gondii-specific IgM test in the newborn's serum. RESULTS: Considering all pregnant women referred to the outpatient unit for high-risk pregnancy in the period of study, frequency of pregnant women with positive Toxoplasma gondii-specific IgM was 10.8% (176/1.634). The rate of congenital infection in these patients was 4% (7/176). The IgG avidity test was performed in 162 patients (92% of the 176 pregnant women with positive IgM), and the avidity was high in 144 (88.9%). There was an association (p=0.003) between high avidity and no fetal/neonatal toxoplasmosis in our sample, with a prevalence ratio of 13.4 (confidence interval [CI] 95% 2.2-86.6). The positive predictive value of the avidity test (probability of congenital infection with a low avidity) was 22% (95% 6%-47%), while the negative predictive value (probability of absence of congenital infection with a high avidity) was 98% (95% CI 94% -99%). CONCLUSIONS: In this study the rate of congenital infection in pregnant women diagnosed with acute toxoplasmosis was 4%. In pregnant women with positive Toxoplasma gondii-specific IgM, results of Toxoplasma gondii-specific IgG avidity test were associated with the presence or absence of congenital infection, with a high negative predictive value (no fetal/neonatal infection when avidity was high).

scholarly journals Introduction to Measurement of Avidity of Anti-Coxiella burnetii IgG in Diagnosis of Q Fever

2019 ◽  
Vol 57 (10) ◽  
Author(s):  
Léa Luciani ◽  
Coralie L’Ollivier ◽  
Matthieu Million ◽  
Bernard Amphoux ◽  
Sophie Edouard ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
High Avidity ◽  
Serum Samples ◽  
Recent Infection ◽  
Urea Treatment ◽  
Content Type ◽  
Avidity Test ◽  
Antigen Complex

ABSTRACT Due to the atypical serological profile of some patients with primary Q fever infection who do not develop IgM against Coxiella burnetii, we developed an avidity test to distinguish recent or past infections. We tested 39 serum samples by immunofluorescence with conventional assay and after urea treatment from 26 patients at different stages of the disease. We observed a strong avidity in the 15 serum samples from patients with infections of >6 months and a low avidity for sera from patients with recent infections. A complete denaturation of the antibody-antigen complex was observed for patients for whom the time since the beginning of infection was <1 month and a mean of 2.06 ± 0.54 lowered titers when the infection was less than 3 months old. That was statistically significant compared to sera from patients with infections of greater than 6 months (mean 0.20 ± 0.41) and with infections between 3 and 6 months (mean, 1.17 ± 0.41) (P = 0.0022 and P < 0.0001, respectively). These results were visualized by Western blotting. We concluded that high avidity (≤1 lowered titer) ruled out infection during the last 6 months and that complete denaturation was related to an infection which had occurred within the previous 3 months. Between these two situations, the avidity test is inconclusive. We suggest using an avidity test for atypical Q fever serology that could be misclassified as residual antibodies (IgG against C. burnetii detected without active or recent infection) and for pregnant women risking obstetrical complications. This new test will dramatically improve the diagnosis and management of patients with Q fever.

scholarly journals Toxoplasma gondii seroprevalence among pregnant women in Rabat, Morocco

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Majda Laboudi ◽  
Zoubida Taghy ◽  
Oussama Duieb ◽  
François Peyron ◽  
Abderrahim Sadak
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Congenital Toxoplasmosis ◽  
Immunoglobulin M ◽  
Bivariate Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Seroprevalence Rate ◽  
Recent Infection ◽  
Igg Avidity ◽  
Avidity Test

Abstract Background Toxoplasmosis is an infectious disease caused by a protozoan parasite named Toxoplasma gondii (T.gondii). Pregnant women are considered one of the risk groups. The objective of this retrospective study is to provide an updated estimate of the seroprevalence of anti-T. gondii antibodies among a group of Moroccan pregnant women monitored at the Parasitology Laboratory of the National Institute of Hygiene in Rabat in Morocco. Methods Serum samples were tested for the presence of specific anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies using indirect enzyme-linked immunosorbent assay (ELISA). Anti-Toxoplasma IgM- and IgG-positive cases were also evaluated with the anti-Toxoplasma IgG avidity test. All cases were evaluated according to the age, parity, and historical of abortion. Results Among 677 pregnant women, 94.1% (637/677) were serologically screened for the first time and therefore had no knowledge of their serological status, and only 5.9% (40/677) were screened for the second or third time. The overall anti-T. gondii IgG and IgM seropositivity among the 637 pregnant women included in the study analysis was 43% (274/637) and 3.9% (25/637), respectively. The use of the IgG avidity test allowed excluding recent infection among 83% of cases with IgG and IgM positive sera. The mean age was 29.4 ± 6.3 years. The result of the bivariate analysis revealed that the age influenced significantly the seroprevalence rate, while the parity and the existence of previous spontaneous abortion did not have any significant statistical correlation with seropositivity to T. gondii. Conclusion This study shows that 43% of pregnant women were positive and 57% of them had no antibody against the T. gondii infection. However, the pregnancy follow-up and the counseling of pregnant women remain essential for the prevention of congenital toxoplasmosis.

scholarly journals Detection of acute Toxoplasma gondii infection in early pregnancy by IgG avidity and PCR analysis

2007 ◽  
Vol 56 (11) ◽  
pp. 1495-1499 ◽  
Author(s):  
Jamshaid Iqbal ◽  
Nabila Khalid
Keyword(s):  
Toxoplasma Gondii ◽  
Early Pregnancy ◽  
Therapeutic Intervention ◽  
First Trimester ◽  
Pcr Analysis ◽  
High Avidity ◽  
Past Infection ◽  
Igm Antibodies ◽  
Igg Avidity ◽  
Avidity Test

Acute Toxoplasma gondii infection in early pregnancy carries the risk of transmitting the infection to the fetus with serious sequelae. However, serological testing for IgG/IgM anti-Toxoplasma antibodies may fail to differentiate between a recent and past infection. Two hundred and twenty-four Kuwaiti women in their first trimester were screened for IgG/IgM antibodies by the Vitek Immuno Diagnostic Assay System (VIDAS) and VIDAS IgG-avidity tests. On serological screening, 119 (53.1 %) women were positive for IgG antibodies and 31 (13.8 %) for IgM antibodies. Nine of the IgM-positive and 7 IgM-negative women had low-avidity antibodies. However, the IgG-avidity test detected low-avidity antibodies only in 9 (29 %) of the 31 IgM-positive women, suggesting a recent infection; 19 (61.3 %) women had high-avidity antibodies, indicating that the infection was acquired in the distant past. Based on IgM serology alone, at least 31 IgM-positive women may have been wrongly labelled as having acute Toxoplasma infection thus warranting appropriate therapeutic intervention. All the 19 IgM-positive women with high-avidity antibodies were confirmed negative for Toxoplasma DNA on PCR analysis. Compared with PCR analysis, the VIDAS avidity test was a helpful tool for the diagnosis of recent Toxoplasma infection in IgM-negative women with low-avidity antibodies and IgM-positive women with high-avidity antibodies; the specificity was >85 –100 %. It is concluded that the VIDAS avidity test when used in combination with VIDAS IgG/IgM tests is a valuable assay for the exclusion of ongoing or recently acquired T. gondii infection in pregnant women in their first trimester and that it decreases significantly the necessity for follow-up testing and unnecessary therapeutic intervention.

scholarly journals Detection of Acute and Chronic Toxoplasma gondii Infection among Women with History of Abortion in the Southwest of Iran

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Jasem Saki ◽  
Maryam Zamanpour ◽  
Mahin Najafian ◽  
Niloofar Mohammadpour ◽  
Masoud Foroutan
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Umbilical Cord ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Normal Delivery ◽  
Blood Samples ◽  
Igg Avidity ◽  
Avidity Test ◽  
History Of

Background. Toxoplasma gondii (T. gondii) is one of the most common intracellular protozoan parasites, which can infect humans and a wide range of mammals and birds. The current study is aimed at investigating the occurrence of T. gondii infection in women with a history of abortion in Khuzestan, Iran. Materials and Methods. A total of 480 women with an abortion history, as well as 200 pregnant women with a normal delivery, were examined in this study. The blood, placenta, and umbilical cord blood samples were assessed by the enzyme-linked immunosorbent assay (ELISA) and nested-polymerase chain reaction (PCR) assay. Results. Based on the results of ELISA assay, the prevalence of toxoplasmosis was 30.83% in women with a history of abortion (25.62% with T. gondii IgG and 5.20% with T. gondii IgM). According to the IgG avidity test, 60.16% of IgG-positive samples showed high avidity, while 27.64% showed low avidity. On the other hand, the prevalence of toxoplasmosis in women with a normal delivery was 23% (21.5% with T. gondii IgG and 1.5% with T. gondii IgM). According to the IgG avidity test, 81.39% of these women showed high avidity, while only 4.65% showed low avidity. Based on the nested-PCR method, T. gondii DNA was detected in 14.18% of blood samples, 4.69% of placental samples, and 1.34% of umbilical cord samples, collected from 148 seropositive women with a history of abortion. Besides, using this method, the parasite DNA was identified in 4.34% of blood samples, collected from 46 seropositive women with a normal delivery, but not in any of the umbilical cord or placenta samples. Conclusion. The present results showed that T. gondii infection contributes to abortion in Khuzestan Province, Iran. Therefore, it is essential to investigate toxoplasmosis in pregnant women, especially in those who are seronegative, using molecular and serological methods and inform them about their disease and the associated risks.

scholarly journals Toxoplasma gondii specific IgG avidity assay: Role and implication in the confirmatory diagnosis of acute toxoplasmosis in seropositive pregnant women

2016 ◽  
Vol 9 (2) ◽  
pp. 96
Author(s):  
Chowdhury Rafia Naheen ◽  
Shirin Tarafder ◽  
Humayun Sattar ◽  
Shafinaz Khan
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Acute Infection ◽  
High Avidity ◽  
Past Infection ◽  
Congenital Transmission ◽  
Avidity Assay ◽  
Igg Avidity ◽  
Avidity Test ◽  
Specific Igg

<p>This study was undertaken to apply<em> Toxoplasma gondii</em> specific IgG avidity test in seropositive pregnant women to differentiate acute and past infection. <em>T. gondii</em> specific IgG avidity test was conducted in 39 seropositive pregnant women and their pregnancy outcomes were observed later on. Out of 39 <em>T. gondii</em> seropositive pregnant women 33 (84%) were only IgG positive and 6 (15.4%) were both IgG-IgM positive. All the IgG positive cases (100%) and 2(33.3%) IgG-IgM positive cases had high avidity antibodies and they gave birth to healthy babies. Rest of the 4 (66.7%) IgG-IgM positive women had low avidity and 50% of them had abortion and 50% gave birth to unhealthy babies. This reveals that the seropositive mothers having high IgG avidity had past infection and no risk of congenital transmission. Seropositive mothers having low IgG avidity had acute infection and so congenital transmission occurred. Presence of<em> T. gondii</em> specific IgG and IgM antibody does not indicate acute infection always. IgG-IgM positive pregnant women should be further evaluated by IgG avidity assay to confirm acute infection.</p><p> </p>

scholarly journals Comparison of Four Commercially Available Avidity Tests for Toxoplasma gondii-Specific IgG Antibodies

2012 ◽  
Vol 20 (2) ◽  
pp. 197-204 ◽  
Author(s):  
O. Villard ◽  
L. Breit ◽  
B. Cimon ◽  
J. Franck ◽  
H. Fricker-Hidalgo ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Pregnant Women ◽  
Predictive Value ◽  
Latent Infection ◽  
High Avidity ◽  
Igg Antibodies ◽  
Content Type ◽  
Initial Testing ◽  
Igg Avidity ◽  
Avidity Test

ABSTRACTToxoplasmainfection in pregnant women may cause congenital toxoplasmosis. Diagnosis of infection is based on serological tests aimed at detecting IgM and IgG antibodies againstToxoplasma gondii. However, IgM antibodies are not an accurate marker for discriminating between acute and latent infection. Detection of residual or persistent IgM may occur months or even years after primary infection, while the IgG avidity test is a rapid means of identifying latent infections in pregnant women who exhibit both IgG and IgM anti-Toxoplasmaantibodies on initial testing during pregnancy. In this study, we assessed and compared the performances of four commercially availableToxoplasmaIgG avidity tests in immunocompetent and immunocompromised patients with acute and latent toxoplasmosis. The positive predictive value of high avidity to confirm latent toxoplasmosis was 100% for all the assays, indicating that high avidity is a hallmark of latent infection. However, the negative predictive value of high avidity ranged from 99.2% (bioMérieux) to 95.3% (Abbott), indicating that acute toxoplasmosis could not be reliably diagnosed based on low IgG avidity alone. Thus, the avidity test provides a rapid means for identifying latentToxoplasmainfection in immunocompetent pregnant women presenting both IgG and IgM anti-Toxoplasmaantibodies on initial testing. In terms of cost-effectiveness, avidity testing is a powerful tool that optimizes screening and follow-up of pregnant women while minimizing the costs of screening by avoiding subsequent costly maternal and fetal investigation and unnecessary treatment. The cheapest assay, Vidas Toxo IgG Avidity, also had the best performance for the diagnosis of latent toxoplasmosis.

scholarly journals Immunoglobulin G Avidity in Diagnosis of Toxoplasmic Lymphadenopathy and Ocular Toxoplasmosis

1999 ◽  
Vol 6 (4) ◽  
pp. 514-518 ◽  
Author(s):  
Malgorzata Paul
Keyword(s):  
Pregnant Women ◽  
Immunoglobulin G ◽  
Large Range ◽  
Congenital Toxoplasmosis ◽  
Chronic Phase ◽  
Ocular Toxoplasmosis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Ocular Infection ◽  
High Avidity ◽  
Igg Avidity

ABSTRACT Traditional serological techniques have some limitations in evaluating the duration of Toxoplasma gondii infection in pregnant women, patients with lymphadenopathy, and older children suspected of having congenital toxoplasmosis. In these three groups of patients, two variants of T. gondii immunoglobulin G (IgG) avidity tests were used: an EIA Kit (Labsystems) and a noncommercial enzyme-linked immunosorbent assay specially elaborated in the laboratory. The avidity of specific IgG in sera from 23 patients with a known recently acquired infection (mainly pregnant women) was low (less than 30%), whereas that in sera from 19 patients with toxoplasmic lymphadenopathy of 3 weeks to 6 months in duration (mean, 8.3 weeks) covered a large range (between 0.2 and 57.8%; mean, 25.7%); high avidity results were observed for 10 of 19 patients (52.6%). The large range of IgG avidity in patients with toxoplasmic lymphadenopathy suggests various durations of infection in these patients, with a tendency for a chronic phase of toxoplasmosis. According to the avidity marker, five patients with lymphadenopathy for less than 3 months did not have a recent Toxoplasma infection. In 6 of 19 patients with lymphadenopathy (31.6%), low IgG avidity values persisted until 5 months after the first serological examination. In all four patients with a documented chronic course of Toxoplasma infection (6 months to 8 years after the first positive serology), high IgG avidity values were observed. Among sera from 10 children and young immunocompetent adults suspected of having ocular reactivation of congenital toxoplasmosis, all had high IgG avidity values (over 40%), suggesting congenitally acquired ocular infection rather than noncongenital infection. In conclusion, the avidity of IgG is a valuable marker of recent toxoplasmosis in pregnant women, suggests the duration of invasion in patients with lymphadenopathy, and may be helpful for differentiation between reactivation of congenital infection and recently acquired ocular toxoplasmosis in immunocompetent patients. A low IgG avidity does not always identify a recent case of toxoplasmosis, but a high IgG avidity can exclude primary infections of less than 5 months’ duration.

scholarly journals Toxoplasma-IgM and IgG-avidity in single samples from areas with a high infection rate can determine the risk of mother-to-child transmission

2006 ◽  
Vol 48 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Myrian Morussi Reis ◽  
Maria Madalena Tessaro ◽  
Pedro Alves D'Azevedo
Keyword(s):  
Pregnant Women ◽  
Congenital Toxoplasmosis ◽  
High Avidity ◽  
Mother To Child Transmission ◽  
Child Transmission ◽  
Serum Samples ◽  
Serologic Marker ◽  
Igg Avidity ◽  
Mother To Child ◽  
Infected Newborn

Anti-Toxoplasma IgG-avidity was determined in 168 serum samples from IgG- and IgM-positive pregnant women at various times during pregnancy, in order to evaluate the predictive value for risk of mother-to-child transmission in a single sample, taking the limitations of conventional serology into account. The neonatal IgM was considered the serologic marker of transmission. Fluorometric tests for IgG, IgM (immunocapture) and IgG-avidity were performed. Fifty-one of the 128 pregnant women tested gave birth in the hospital and neonatal IgM was obtained. The results showed 32 (62.75%) pregnant women having high avidity, IgM indexes between 0.6 and 2.4, and no infected newborn. Nineteen (37.25%) had low or inconclusive avidity, IgM indexes between 0.6 and 11.9, and five infected newborns and one stillbirth. In two infected newborns and the stillbirth maternal IgM indexes were low and in one infected newborn the only maternal parameter that suggested fetal risk was IgG-avidity. In the present study, IgG-avidity performed in single samples from positive IgM pregnant women helped to determine the risk of transmission at any time during pregnancy, especially when the indexes of the two tests were analysed with respect to gestational age. This model may be less expensive in developing countries where there is a high prevalence of infection than the follow-up of susceptible mothers until childbirth with monthly serology, and it creates a new perspective for the diagnosis of congenital toxoplasmosis.

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