BackgrounchMaternal seroconversion for Toxoplasma gondii during
pregnancy is said to have good role for diagnosis of congenital infection.
Objective: to determine whether maternal serum levels of antibodies
against Toxoplasma gondii parasite are associated with definite fetal
parasitic infectation and consequent pathology or not.
Patients and Methods: Maternal serum IgA levels against Toxoplasma
gondii were measured in 29 patients with strongly suggested congenital
toxoplasmosis (maternal IgM seroconversion with fetal pathology) out of
200 patients with suggestive fetal pathology. Their pregnancies were
affected by hydrocephalus (Group 1, n=17), other congenital anomalies
and hydropes fetalis (Group II, n=6), and fetal loss (Group III, n=6). They
were compared with 17 women with negative IgM and normal pregnancies
as a control group (Group IV). All cases were examined by
ultrasonography for obtaining amniotic fluid samples during pregnancy.
After termination and if possible fetal serum samples were drawn for
measuring the same antibodies. Also, placental imprints, placental samples
and umbilical cord samples were prepared for histopathological
examination for detection of parasite cysts in tissues.
Results: Cases presented by maternal IgM seroconversion against
Toxoplasma gondii during pregnancy with suggestive fetal pathology
(hydrocephalus, other anomalies, and abortions) showdd significantly
higher maternal specific Toxoplasma IgA levels than the control group
(166.7±27.2, 165.7±2I.l, and 149.7±9.1 respectively vs. 127.2±15.3,
p>0.001). Microscopic parasitic detection was positive in 2/11 (18.25) in the
amniotic fluid and in 1/11 (9.1%) in placental tissues of these cases.
Conventional serological neonatal testing for specific Toxoplasma IgA
revealed sensitivity and specificity of 77.8% and 100% respectively. The
combination of the results of conventional serological neonatal testing for
specific Toxoplasma IgA with the results of parasitic detection (amniotic
fluid and placental) resulted in sensitivity and specificity of 94.4 and 100
respectively.
Conclusions: Detection of specific Toxoplasma gondii IgA antibody
response by ELISA is more reliable than IgM level for diagnosis of
congenital toxoplasmoisis.