ABSTRACT
Diagnostic Products Corporation has chosen chemiluminescent for the new kit of quantitative measurement of IgG and qualitative detection of IgM antibodies to Toxoplasma gondii, 878 human sera of principal diagnosis situations were tested, and the results obtained with the IMMULITE Toxoplasmosis kit were compared with those of the Parasitology and Mycology Laboratory of the University of Lille. Chemiluminescent allows a sensitive and specific determination of immunity. In the same ways, this method is able to detect earlier specific IgM and IgG during seroconversion. The kit of quantitative measurement of IgG and qualitative detection of IgM is reproducible and sensitive; this confirms the interest for the pediatric diagnosis of congenital toxoplasmosis.
Subject(s)
Luminescent Measurements , Pregnancy Complications, Parasitic/diagnosis , Toxoplasmosis/diagnosis , Aged , Animals , Female , Humans , Immunoenzyme Techniques , Immunoglobulin G/blood , Immunoglobulin M/blood , Infant, Newborn , Pregnancy , Toxoplasma/immunology , Toxoplasmosis/blood , Toxoplasmosis/complications , Toxoplasmosis, Animal , Toxoplasmosis, Congenital/blood , Toxoplasmosis, Congenital/diagnosisABSTRACT
BACKGROUND: The survival of T gondii bradyzoites in cysts explains clinical recurrences and serological rebounds after birth in children with congenital toxoplasmosis. At the present time, management of such manifestations is not well defined. PATIENTS AND METHODS: Sixty-three infants with congenital toxoplasmosis were followed-up at the University Hospital of Lille (France) during the first two years of life. For each child, the treatment before and after birth was well defined. Clinical, ophthalmological, radiological and serological data were collected every third month. Serological assays specially adapted to this age bracket were used for the quantification of specific IgG, or for the detection of T gondii specific IgM and IgA. RESULTS: Seventy-six serological rebounds were reported in 55 of the 63 children (87%). They concerned essentially IgG (96%) and less frequently IgM (47%) or IgA (60%). At the same time, only five clinical recurrences were observed, four of them being preceded by a serological rebound. DISCUSSION: Treatment of fetuses or children with pyrimethamine and sulfonamides versus spiramycin alone was associated with a decrease in the frequency of serological rebounds during the first year of life (P < 0.001). Such a therapeutic regimen during the second year of life decreases the appearance of serological rebounds in children without rebound antecedent (P < 0.001). CONCLUSION: The increase in number of rebounds after the end of a course of pyrimethamine and sulfonamides necessitates the evaluation of such a long term treatment without interruption.
Subject(s)
Toxoplasmosis, Congenital/complications , Child, Preschool , Cohort Studies , Female , Follow-Up Studies , Humans , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Immunologic Surveillance , Infant , Infant, Newborn , Pregnancy , Pregnancy Complications, Parasitic/drug therapy , Toxoplasmosis/drug therapy , Toxoplasmosis, Congenital/drug therapy , Toxoplasmosis, Congenital/immunologyABSTRACT
Tachyzoite-bradyzoite interconversion is one characteristic feature of Toxoplasma gondii. Although highly similar in structure, tachyzoite and bradyzoite differ by the relative amount of certain organelles and by specific surface or cytoplasmic molecules. Differences in structure and contents also exist between parasitophorous vacuoles and cysts. Using stage specific markers, it was shown the quickness of stage switching in vivo as well as in vitro, together with the occurrence of intermediate stages. Regulatory mechanisms of interconversion remain unknown. However, stress or inhibition of the mitochondrial metabolism of the parasite trigger bradyzoite formation.
