Aggressive natural killer cell leukemia (ANKL) is a very rare lymphoproliferative cancer that starts in NK cells. In this condition, the body produces NK lymphocytes in large amounts. Natural killer (NK) cells are a type of lymphocyte that are closely related to T cells and attack foreign cells. They are often the body’s first line of defence against infection. Aggressive NK-cell leukemia is characterized by large granular lymphocytes, which are bigger than normal lymphocytes.
ANKL occurs more often in younger people of Asian descent. It occurs most often in people in their 30s. Although the exact cause of ANKL is not known, it is strongly associated with the Epstein-Barr virus.
ANKL usually involves the blood and bone marrow, but it can also occur in the liver or spleen. People with ANKL usually have:
Lymph nodes may also be enlarged. Blood clotting problems can also occur, such as disseminated intravascular coagulation (DIC). Failure of many organs (multi-organ failure) can also happen.
ANKL is usually a rapidly progressive disease that often has a poor prognosis. Although very rare, there is also a chronic NK-cell leukemia, which is more slow-growing (indolent) and has a more favourable prognosis. Chronic NK-cell leukemia is treated similarly to T-cell large granular lymphocytic leukemia.
ANKL is treated with chemotherapy. It does not respond well to conventional chemotherapy used for most lymphomas.
ANKL is often treated with intensive chemotherapy and central nervous system (CNS) prophylaxis, similar to that used to treat acute lymphocytic leukemia (ALL). For more information on ALL-like treatments used for aggressive NK-cell leukemia, go to ALL.
A stem cell transplant (SCT) may be offered to some people with ANKL who respond to initial induction chemotherapy.