Genotypes of T. Gondii in Patients With Haematological Malignancies at a State Cancer Institute in South India

Abstract

BACKGROUND Toxoplasma gondii (T. gondii) is considered to be an important opportunistic pathogen in immunocompromised patients. After the advent of highly-activated antiretroviral therapy, though the frequency of opportunistic toxoplasmosis in the developed world has decreased, it continues to be a crucial aetiology of focal brain lesions in AIDS in developing countries such as India. Likewise, toxoplasmosis is a common infectious complication in patients with Haematological Malignancies (HM) on Stem Cell Therapy (SCT). Non-stem cell transplant patients treated with aggressive immunosuppressive regimens are also at risk for this opportunistic parasitic infection. We had earlier shown that about 14% of febrile episodes in non-stem cell transplant patients with HM were attributed to T. gondii infection. The aim of the study was to identify genetic types of Toxoplasma gondii (T. gondii) during febrile episodes in patients with Haematological Malignancies (HM). MATERIALS AND METHODS Febrile episodes in 210 patients with HM were investigated for T. gondii infection during November 2012 to April 2013. Blood samples were tested for B1 gene of the parasite and DNA from the positive episodes was taken up for multilocus PCR-Restriction Fragment Length Polymorphism (RFLP) genotyping. Direct amplification of 10 different loci, viz. SAG1, 5'-3'SAG2, alt. SAG2, SAG3, BTUB, GRA6, C22-8, L358, PK1 and APICO followed by RFLP was used to genotype the parasite. Sera from samples with amplifiable T. gondii B1 gene were also tested for IgM and low avidity IgG antibodies to the parasite.