The expression of the novel cytotoxic protein granzyme M by large granular lymphocytic leukaemias of both T-cell and NK-cell lineage: an unexpected finding with implications regarding the pathobiology of these disorders.
Granzyme M (GrM) is a novel cytotoxic protein normally exclusively expressed by natural killer (NK)-cells and cytotoxic T-cells with innate immune function. As most T-cell granular lymphocytic leukaemias (T-LGL) are thought to be derived from the adaptive immune system it was predicted that T-LGL would be GrM negative. Contrary to this hypothesis, bone marrow biopsy immunohistochemistry revealed that GrM was frequently expressed in both T-LGL (16 / 18) and NK-LGL (6 / 9). These unexpected results suggest commonality between T- and NK-LGL, providing further support to the notion that T-LGL is a disorder of dysregulated, chronically stimulated, adaptive cytotoxic T-cells.
Morice
William G
WG
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA. morice.william@mayo.edu
Jevremovic
Dragan
D
Hanson
Curtis A
CA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019070:Cell Lineage; D053804:Granzymes / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007694:Killer Cells, Natural / Q000276:immunology*; D007945:Leukemia, Lymphoid / Q000201:enzymology* / Q000276:immunology; D015458:Leukemia, T-Cell / Q000201:enzymology / Q000276:immunology; D008875:Middle Aged; D039102:Poly(A)-Binding Proteins / Q000032:analysis; D000074019:T-Cell Intracellular Antigen-1; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D039102:Poly(A)-Binding Proteins; D000074019:T-Cell Intracellular Antigen-1; C071558:TIA1 protein, human; C509218:GZMM protein, human; D053804:Granzymes