title: Chronic lymphatic leukemias of T and NK cell type.
abstract: T cell chronic lymphocytic/prolymphocytic leukemia (T-CLL/T-PLL) and large granular lymphocyte leukemia of T or NK cell type (T-LGL or NK-LGL leukemia) are chronic lymphoproliferative diseases derived from post-thymic immunocompetent lymphoid cells. T-PLL is morphologically characterized by a prominent central nucleolus in a medium-sized cell expressing a mature T cell immunophenotype. Clonal genetic changes involving chromosome 14 and T cell receptor gene rearrangements are characteristics of these diseases. They are usually progressive and there is no efficient treatment available. The classification of some cases presenting with a morphological picture similar to B-CLL, but with immunophenotypic and clinical features resembling T-PLL, as T-CLL is still controversial. The phenotypic profiles and the establishment of clonality are the hallmarks of defining T-LGL leukemia and NK-LGL leukemia. The CD3+/CD57+/CD56- immunophenotype and the clonal rearrangement of the T cell receptor genes characterize T-LGL leukemia, which presents clinically with a rather indolent course of disease, complicated by frequent infections secondary to neutropenia. NK-LGL leukemia cells express CD3-/CD56+/CD57-, but in most cases clonality cannot easily be established. Clinically the patient may either present with constitutional symptoms and suffer a short and aggressive course of disease or may have a more chronic disease similar to T-LGL leukemia. Therefore, it may be reasonable to subdivide NK-LGL proliferation into the more aggressive 'NK-LGL leukemia/lymphoma' and 'chronic NK cell lymphocytosis'.
authors.affiliation: Klinik und Poliklinik für Innere Medizin mS Hämatologie und Onkologie, Virchow Klinikum, Humboldt Universität, Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kingreen
authors.forename: W
authors.initials: W
authors.lastname: Siegert
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D003937:Diagnosis, Differential; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000276:immunology*; D015461:Leukemia, Prolymphocytic, T-Cell / Q000145:classification / Q000235:genetics / Q000276:immunology* / Q000628:therapy; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD