Lymphoid leukemias are a group of leukemias affecting circulating lymphocytes, a type of white blood cell. The lymphocytic leukemias are closely related to lymphomas of the lymphocytes, to the point that some of them are unitary disease entities that can be called by either name (for example, adult T-cell leukemia/lymphoma). Such diseases are all lymphoproliferative disorders. Most lymphoid leukemias involve a particular subtype of lymphocytes, the B cells. Classification
Historically, they have been most commonly divided by the stage of maturation at which the clonal (neoplastic) lymphoid population stopped maturing:
Acute lymphoblastic leukemia
Chronic lymphocytic leukemiaHowever, the influential WHO Classification (published in 2001) emphasized a greater emphasis on cell lineage. To this end, lymphoid leukemias can also be divided by the type of cells affected:

B-cell leukemia
T-cell leukemia
NK-cell leukemiaThe most common type of lymphoid leukemia is B-cell chronic lymphocytic leukemia. B-cell leukemias
B-cell leukemia describes several different types of lymphoid leukemia which affect B cells. Other types include (with ICD-O code):

9826/3 – Acute lymphoblastic leukemia, mature B-cell type
9833/3 – B-cell prolymphocytic leukemia
9940/3 – Hairy cell leukemia

T-cell leukemias
T-cell leukemia describes several different types of lymphoid leukemias which affect T cells.The most common T-cell leukemia is precursor T-cell lymphoblastic leukemia. It causes 15% of acute leukemias in childhood, and also 40% of lymphomas in childhood. It is most common in adolescent males. Its morphology is identical to that of precursor B-cell lymphoblastic leukemia. Cell markers include TdT, CD2, CD7. It often presents as a mediastinal mass because of involvement of the thymus.
NK cell therapy
Natural killer (NK) cell therapy is used in pediatrics for children with relapsed lymphoid leukemia. These patients normally have a resistance to chemotherapy, therefore, in order to continue on, must receive some kind of therapy. In some cases, NK cell therapy is a choice.NK cells are known for their ability to eradicate tumor cells without any prior sensitization to them. One problem when using NK cells in order to fight off lymphoid leukemia is the fact that it is hard to amount enough of them to be effective. One can receive donations of NK cells from parents or relatives through bone marrow transplants. There are also the issues of cost, purity and safety. Unfortunately, there is always the possibility of Graft vs host disease while transplanting bone marrow. NK cell therapy is a possible treatment for many different cancers such as Malignant glioma. References


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