Determination of Low IgG Class Antibody Avidity Percentage by IgM Levels Specific to Toxoplasma Gondii
Clinical Laboratory, cilt.68, sa.8, ss.1695-1701, 2022 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 68 Sayı: 8
- Basım Tarihi: 2022
- Doi Numarası: 10.7754/clin.lab.2021.211112
- Dergi Adı: Clinical Laboratory
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, EMBASE, MEDLINE
- Sayfa Sayıları: ss.1695-1701
- Anahtar Kelimeler: Toxoplasma gondii, IgM, serological diagnosis, avidity, primary infection
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Background: Ig (Immunglobulin) M detection and low avidity index are markers of recent infection in differenti-ating acute and chronic stages of Toxoplasma gondii (T. gondii) infections. In this study, we aimed to evaluate whether the anti-T. gondii IgM antibody index threshold value could be a predictive factor in the estimation of low avidity and its use in improving the diagnosis of early toxoplasma infection. Methods: Anti-T. gondii IgM, IgG antibody and IgG avidity results were analyzed. Anti-T. gondii IgG and IgM an-tibodies in blood samples were studied with chemiluminescent microparticle immunoassay (CMIA), and IgG avid-ity test was performed with Enzyme Linked Fluorescent Assay (ELFA) technique. Results: The overall seroprevalence of anti-T. gondii antibodies (IgG and/or IgM) was 19.4%. Of the 64 patients whose avidity tests were studied, 47 (73.4%) were female. Twenty seven (57.4%) of the women were pregnant. In the IgG avidity test, 7.8% low avidity was detected. Low avidity was detected in only 4 (15.4%) of 26 IgM positive cases. IgM analysis of a case (6-month-old baby) with low avidity was found to be negative. In the prediction of low avidity, the assay's IgM positivity cutoff value was ≥ 0.6, its sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 62.7%, 2.3%, and 99.7%, respectively. With Architect, 37.3% of samples were false positive. Determining the IgM index cutoff value was unsuccessful in distinguishing low avidity. The area under the ROC curve was 0.574 (p = 0.60). Conclusions: In our study, the positive predictive value of the IgM test kit in estimating low avidity was low and the false positivity rate was 37.3%. It is thought that the index cutoff value of the anti-T. gondii IgM antibody test kit cannot be considered as a good predictor of recent infection. Studies with larger patient groups are needed.