Impotent B cells
Antibodies are produced by B cells and are critical for the clearance of invading microoganisms. A variety of antibodies exist and “switch” from one type to another during infection. In individuals with chronic lymphocytic leukemia (CLL), antibody production and switching is severely impaired and this is associated with increased susceptibility to bacterial infections. The mechanisms behind these immune defects have remained elusive.
In the February issue of Nature Immunology (Vol. 2, No. 2, 01 Feb 2001), scientists have investigated how leukemia cells interfere with normal B cell function. It turns out that the culprit is dysregulated expression of CD30, a molecule which is associated with several immune deficiency syndromes such as AIDS. Under certain conditions, CD30 is expressed by T cells. If these CD30-expressing T cells interact with B cells during an immune response, the B cells do not progressively mature to switch-on various required antibody types. This impairs a patient’s ability to resist infection. Another consequence is the enhanced production of an immune modulator that promotes the growth of leukemic B cells. Thus, a novel therapeutic approach to controlling this leukemia may be to disrupt the leukemia cell–T cell interaction by blocking CD30 or its ligand.
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(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza