Early and Accurate Diagnosis of Congenital Toxoplasmosis

Pediatr Infect Dis J. 2008 Feb;27(2):125-9. doi: 10.1097/INF.0b013e3181586052.


Objective: Early diagnosis of congenital toxoplasma infection is difficult to establish using serological methods. We explored specific T cell immunity to Toxoplasma gondii antigens to identify more accurate diagnostic tests for an early diagnosis of toxoplasma infection in newborns at risk for congenital toxoplasmosis.

Study design: T lymphocyte proliferation, interferon (IFN)-gamma production and lymphocyte activation antigens expression were evaluated in 23 infected and 65 uninfected neonates at different times, in the first year of life.

Results: The immunologic tests accurately discriminated when tested <or=90 and >90 days of age, respectively and were significantly lower in uninfected than in infected infants: activation antigen CD25, P < 0.001 and P < 0.00001; activation antigen histocompatibility leukocyte antigen (HLA)-DR, P < 0.01 and P < 0.00001; T cell proliferation, P < 0.0001 and P < 0.00001; IFN-gamma production, P < 0.001 and P < 0.00001. Evaluation of the specific T cell response allowed identification at 3 months of age or younger, 2 of 23 infected neonates, who had negative serologic tests. Moreover specific T lymphocyte activity increased with age even in neonates undergoing therapy, suggesting that medical treatment does not affect lymphocyte response.

Conclusions: Evaluation of T cell immunity is important for an early and accurate diagnosis of congenital toxoplasmosis.

MeSH terms

  • Antigens, Protozoan / immunology
  • Cell Proliferation
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • T-Lymphocytes / physiology
  • Toxoplasmosis, Congenital / diagnosis*
  • Toxoplasmosis, Congenital / immunology


  • Antigens, Protozoan