Value of the polymerase chain reaction for the detection of Toxoplasma gondii in cerebrospinal fluid from patients with AIDS.

To investigate whether the polymerase chain reaction (PCR) on the BI gene of Toxoplasma gondii could contribute to the diagnosis of cerebral toxoplasmosis in patients with AIDS, we retrospectively tested CSF samples from 20 patients with AIDS suspected of having cerebral toxoplasmosis for the presence of T. gondii. Suspicion of cerebral toxoplasmosis was based on accepted criteria. Nine patients with AIDS with IgG antibodies to T. gondii but who were not suspected of having cerebral toxoplasmosis and four patients with AIDS seronegative for T. gondii served as negative control patients. T. gondii was demonstrated by PCR in the CSF from 13 of the 20 patients with AIDS suspected of having cerebral toxoplasmosis but was not demonstrated in the CSF samples from the nine control patients seropositive for T. gondii and the four control patients seronegative for T. gondii. The data were statistically evaluated. This study shows the value of PCR for the detection of T. gondii in CSF for the diagnosis of cerebral toxoplasmosis in patients with AIDS.