GENE AMPLIFICATION IN THE BIOLOGICAL DIAG NOSIS OF TOXOPLASMOSIS

Biological diagnosis of toxoplasmosis is generally based on indirect a rguments (serology). In cases of immaturity or of immune depression, h owever, evidence of the parasite has to be obtained. This involves tim e-consuming or relatively insensitive culture techniques. Molecular bi ology, and more particularly the polymerase chain reaction gene amplif ication technique, makes it possible to identify an extremely small qu antity of parasites in a complex biological fluid in a few hours. We s ummarized our experience with an original technique using toxoplasma r ibosomal DNA as the target. Its use in the amniotic fluid provides a d istinct improvement in antenatal diagnosis and is fast becoming the te chnique of reference. Difficult cases have been solved by its applicat ion in ophtalmology. Finally, in immunodepressed patients, especially in cases of acquired immunodeficiency syndrome, assessment is currentl y ongoing. The results obtained so far, especially in the analysis of the cerebral spinal fluid, are encouraging.