Large granular lymphocytic leukemia is a disease that exhibits an unexplained, chronic (> 6 months) elevation in large granular lymphocytes (LGLs) in the peripheral blood.
It is sometimes known as T-cell large granular lymphocyte leukemia (specifying involvement of the T cells). However, NK large granular lymphocyte leukemia (involving natural killer cells) is also possible.
It is also known by the following terms: proliferation of large granular lymphocytes (LGLs), LGL leukemia, Tγ-lymphoproliferative disorder, and, in common with other T cell leukemias such as T-cell prolymphocytic leukemia, T-cell chronic lymphocytic leukemia.
T-LGL is a rare form of leukemia, comprising 2-3% of all cases of small lymphocytic leukemias.
The postulated cells of origin are a transformed CD8+ T-cell with clonal rearrangements of β chain T-cell receptor genes for the majority of cases and a CD8- T-cell with clonal rearrangements of γ chain T-cell receptor genes for a minority of cases.
This disease is known for an indolent clinical course and incidental discovery. The most common physical finding is moderate splenomegaly. B symptoms are seen in a third of cases, and recurrent infections due to the associated neutropenia are seen in almost half of cases.
Clonal rearrangements of the T-cell receptor (TCR) genes are a necessary condition for the diagnosis of this disease. The gene for the β chain of the TCR is found to be rearranged more often than the γ chain. of the TCR.
Alemtuzumab has been investigated for use in treatment of refractory T-cell large granular lymphocytic leukemia.
^Loughran TP, Kadin ME, Starkebaum G, et al. (February 1985). "Leukemia of large granular lymphocytes: association with clonal chromosomal abnormalities and autoimmune neutropenia, thrombocytopenia, and hemolytic anemia". Ann. Intern. Med.102 (2): 169–75. doi:10.7326/0003-4819-102-2-169. PMID3966754.