t-cell leukemia t-cell leukemia t-cell leukemia describes several different types of lymphoid leukemia which affect t cells. t-cell leukemiaspecialtyimmunology, oncology, angiology types include: large granular lymphocytic leukemia adult t-cell leukemia/lymphoma t-cell prolymphocytic leukemia in practice, it can be hard to distinguish t-cell leukemia from t-cell lymphoma, and they are often grouped together.