Toxoplasma gondii infection during pregnancy: T lymphocyte subpopulations in mothers and fetuses.

Prenatal diagnosis of fetal toxoplasmosis is possible with the use of fetal blood sampling, amniocentesis and ultrasound examination. The purpose of this study was to describe T lymphocyte subsets (CD3, CD4 and CD8) in mothers and their fetuses when Toxoplasma gondii infection occurred during pregnancy. Maternal and fetal blood samples were obtained in 86 cases and 9 fetuses showed T. gondii infection. Control groups consisted of 30 healthy nonpregnant women and 30 pregnant women. Pregnant women with T. gondii infection showed an increase in the suppressor (CD8) T subpopulation and a significant depression in the total helper (CD4) T cells. These alterations were more important in mothers whose fetus was infected. We showed the progressive maturation of the fetal immune system with a regular increase of all T lymphocyte subsets. Marked alterations were observed in the 9 infected fetuses (depression of CD4 population and lower CD4/CD8 ratio). In the future these differences might be used as a new marker of the severity of fetal lesions and become a useful diagnostic tool.