Detection of Toxoplasma DNA in the Peripheral Blood of HIV-Positive Patients with Neuro-opportunistic Infections by a Real-Time PCR Assay

We determine if peripheral blood sample could be used for diagnosis of cerebral toxoplasmosis by a real-time PCR assay and we analyzed the clinical and laboratory findings in 22 patients with confirmed cerebral toxoplasmosis compared to 27 patients with other neuro- opportunistic infections. We compared two gene targets (B1 and RE) in the Taqman-PCR real-time assay. Efficiency values were also calculated. We found that 18.8% (4/22) of cases with cerebral toxoplasmosis and 7.4% (2/27) of patients with other neuroinfections had positive results with the Taqman PCR assay. The mean number of parasites was 67.7 (SD 69.0) tachyzoites/mL in patients with cerebral toxoplasmosis and of 31.8 (SD 6.3) tachyzoites/mL in other neuroinfections. Clinical symptoms as headache were significantly less frequent and focal neurological symptoms were significantly more frequent in cerebral toxoplasmosis than in other neuroinfections. In our conditions, real- time PCR on peripheral blood samples was not useful for diagnosis of cerebral toxoplasmosis.