Early and accurate diagnosis of congenital toxoplasmosis.
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.


METHODS
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.
Ciardelli
Laura
L
Research Laboratories (Neonatal Immunology and Paediatric Oncohematology), University of Pavia, Italy. l.ciardelli@smatteo.pv.it
Meroni
Valeria
V
Avanzini
Maria Antonietta
MA
Bollani
Lina
L
Tinelli
Carmine
C
Garofoli
Francesca
F
Gasparoni
Antonella
A
Stronati
Mauro
M
D000953:Antigens, Protozoan / Q000276:immunology; D049109:Cell Proliferation; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013601:T-Lymphocytes / Q000502:physiology; D014125:Toxoplasmosis, Congenital / Q000175:diagnosis* / Q000276:immunology
D000953:Antigens, Protozoan