Ninety eight patients with Acute myeloid leukemia (AML), Acute Lymphoblastic Leukemia (ALL) and lymphoma, selected from patients referring to Imam Reza Hospital of Tabriz (38°04′N 46°18′E), in terms of the presence of anti-Toxoplasma IgM, IgG, IgG avidity antibodies and the major risk factors were evaluated. This evidence concerns the gene CD40LG and acute lymphoblastic leukemia.