Early and Accurate Diagnosis of Congenital Toxoplasmosis

Pediatr Infect Dis J. 2008 Jan 2 [Epub ahead of print]

Early and Accurate Diagnosis of Congenital Toxoplasmosis.

Ciardelli L, Meroni V, Avanzini MA, Bollani L, Tinelli C, Garofoli F, Gasparoni A, Stronati M.

From the *Research Laboratories (Neonatal Immunology and Paediatric Oncohematology), †Infectious Diseases Department, University of Pavia, ‡Neonatal Intensive Care Unit, and §Biometric Unit, Fondazione IRCCS Policlinico San Matteo, Pavia; and ∥Neonatal Intensive Care Unit, Spedali Civili, Brescia, Italy.

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 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.

PMID: 18174870 [PubMed - as supplied by publisher]