Seroprevalence and molecular evaluation of toxoplasmosis in children with cancer in Khuzestan province, Southwest of Iran.

Toxoplasma gondii is an intracellular parasite with global distribution. Toxoplasmosis in individuals with normal immune system is usually asymptomatic, but in immunocompromised patients may lead to death if not cured. In this study, the prevalence rate of acute and chronic toxoplasmosis in children with cancer was investigated using serological and molecular methods. Blood samples were taken from 372 children with cancer in Shafa hospital in Ahvaz, southwest of Iran. Anti- T. gondii IgG and IgM antibodies were investigated by ELISA. The presence of Toxoplasma in the blood samples was evaluated by Nested PCR. Among 372 children with cancer, 155 (41.7%) were positive for anti- T. gondii IgG antibodies and 24 (6.4%) were positive for anti- T. gondii IgM antibodies, as well. In IgG avidity test, 34 (22%) had antibodies indicating acute phase and 121 (78%) had antibodies indicating chronic phase. The Nested PCR results were showed T. gondii parasite in 34 (100%) patients among 34 IgG antibody-positive patients with acute infection, among 16 IgG antibody-positive patients with chronic infection, 10 patients were indicative of T. gondii and 6 patients were not indicative of T. gondii . A total of 50 cases, 44 (88%) were T. gondii -positive and 6 (12%) were T. gondii -negative in Nested PCR. This study showed high prevalence of toxoplasmosis in children with cancer. Results of serological techniques (ELISA and IgG avidity) had a higher overlap with Nested PCR in identifying T. gondii of seropositive patients.