TIA-1 antibody (T-cell intracytoplasmic antigen) is expressed in lymphocytes processing cytolytic potential. Studies show that 60 to 70% of anaplastic large cell lymphoma reacts with TIA-1. Studies also indicate that TIA-1 reacts with most large granular lymphocytic leukemias, hepatosplenic T-cell lymphomas, intestinal T-cell lymphomas, NK-like T-cell lymphomas, NK cell lymphomas, nasal T/NK-cell lymphomas, subcutaneous T-cell lymphomas and pulmonary angiocentric lymphomas of T-or NK-phenotype. All B-cell lymphomas, Hodgkin’s and lymphoblastic leukemias were negative for TIA-1.