T-cell lymphoma
A disease in which cells in the lymphoid system called T cells (or T lymphocytes) become malignant. T-cell lymphomas account for a minority (about 15%) of non-Hodgkin lymphomas in the US and are more common in Asia.
The T-cell lymphomas are highly diverse and include lymphoblastic lymphoma (mainly in children and adolescents, where they account for about half of pediatric lymphomas); peripheral T-cell lymphoma (a heterogeneous group of generally aggressive diseases); mycosis fungoides (called Sézary syndrome if the malignant T cells circulate in blood); and some anaplastic large cell lymphoma (ALCL), both primary cutaneous and systemic ALCL.
T-cell lymphoma may involve the bone marrow but it usually comprises less than 25% of the marrow. If 25% or more of the marrow is populated by the malignant T cells, it is considered T-cell leukemia.
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- T-cell receptor
A device used by T cells for recognizing specific antigens. T cells have receptors that are activated exclusively by a target antigen.
- T-helper cell
those that activate other T cells to achieve cellular inflammatory responses; and those that drive B cells to produce antibodies in the humoral immune response. These two classes of response are generally incompatible with one another and require coordination by substances called cytokines to promote one response while dampening the other. The HIV virus attacks […]
- T-suppressor cell
A type of immune cells, also called CD8 cells, these cells close down the immune response after it has destroyed invading organisms. CD8 cells are sensitive to high concentrations of circulating lymphokine hormones and release their own lymphokines after an immune response has achieved its goal, signaling all other participants to cease their attack. Some […]
- T-suppressor cells
T cells that express the CD8 transmembrane glycoprotein (CD8+ T cells). They close down the immune response after invading organisms are destroyed. Suppressor T cells are sensitive to high concentrations of circulating lymphokine hormones, and release their own lymphokines after an immune response has achieved its goal. This signals all other immune-system participants to cease […]
- T-suppressor count
A test that counts the number of T-suppressor (T-8) cells in the bloodstream. It appears that some T-8 cells secrete a substance that can kill the HIV virus, so a high count is believed to be a good indicator for people with HIV (AIDS). See also T- suppressor cells.