Serological and Molecular Investigation of Toxoplasmosis Using B1 Gene in HIV-Positive Patients in Tehran

Toxoplasma gondii is an obligate intracellular parasite with global distribution. Diagnosis of Toxoplasma gondii infection with high sensitivity and specificity is very important in managing and treating this disease. The purpose of this study is serological and molecular investigation of toxoplasmosis using B1 gene in HIV- positive patients referred to hospitals affiliated with Iran University of Medical Sciences.

In this study, 660 blood samples were collected from HIV/AIDS- positive patients referred to hospitals affiliated with Iran University of Medical Sciences. Patient samples were examined for the presence of IgG and IgM antibodies against Toxoplasma gondii using an ELISA kit. Genomic DNA was extracted from the patient's serum, as well as peripheral blood mononuclear cell (PBMC) and whole blood samples, and then Real time-PCR was performed.

Although IgG antibody against Toxoplasma gondii was positive in 158 (23.9%) patients out of 660 HIV- positive patients, IgM antibody was positive in 5 (0.76%) patients. The results of Real-Time PCR showed that 7 (1.06%) patients were positive in PBMC samples, of which five patients were positive for IgM antibodies against Toxoplasma gondii while two patients had high- level Toxoplasma IgG antibody titers.

The results of the study indicate that the Real-time PCR method using PBMC DNA samples is a suitable method for the diagnosis of toxoplasmosis. This method, together with the antibody test, especially the high titer of Toxoplasma IgG antibodies, can be helpful in the diagnosis of toxoplasmosis.