TOXOPLASMA GONDII IGG AVIDITY IN DISCRIMINATING BETWEEN ACUTE AND CHRONIC TOXOPLASMOSIS IN NEONATAL CHOLESTASIS

Abstract

Toxoplasma IgM (IgM) is a sensitive indicator of primary toxoplasmosis; but with limited specificity,and it may occasionally be sustained in blood serum for extended periods, ranging from severalmonths to years, following the first infection. The Toxo IgG avidity assay is a currently employed diagnosticmethod for accurately assessing the time it takes to acquire an infection and determining theinitial T. gondii infection. This study evaluated Toxoplasma IgG avidity testing in new-borns diagnosedwith cholestasis on 92 neonates presented with cholestasis, whose blood samples were assessedfor the presence of toxoplasmosis using IgG and Toxo IgG Avidity ELISA tests. Biochemical changesincluding the lipid profile, liver and renal functions were also evaluated. ELISA test revealed ToxoIgG seropositivity at 52.2% (29.43±17.86IU/ml). Toxo IgG avidity tested low at 56.5%, high at34.8%, and borderline at 8.7% (0.38 ±0.31) with a significant association (P<0.001) at a cut-off valueof 0.315. IgG titre was significantly correlated with direct bilirubin (P=0.029), AST (P<0.001), ALT(P<0.001), ALP (P=0.041), PC (P=0.003), INR (P=0.041), urea (P=0.021), and triglyceride (P=0.022).Toxo IgG avidity showed a significant (P<0.001) negative association with total bilirubin, direct bilirubin,AST, ALT, PT, INR, and a significant positive association with PC (P<0.001), GGT (P=0.01).