[Large granular lymphocyte leukemia: clinical and pathogenic aspects]

Large granular lymphocyte leukemia (LGL) is a hematologic disorder characterized by a monoclonal expansion of large lymphocytes containing azurophilic granules with a T CD3(+)CD57(+) or Natural Killer (NK) CD3(-)CD56(+) phenotype. The World Health Organization (WHO) classification identifies three entities: the T LGL, the chronic lymphoproliferative disorder of NK-cells, and the aggressive NK-cell leukemia. T LGL and chronic lymphoproliferative disorder of NK-cells are indolent diseases frequently associated with cytopenias and a wide spectrum of auto-immune manifestations. Neutropenia can lead to recurrent bacterial infections, which represent an indication of initiating a treatment in most of the cases. Immunosuppressive therapies are usually used in this context. In contrast, aggressive NK-cell leukemia follows a fulminant course with a poor prognosis because patients are refractory to most of the treatments. There is now a considerable interest in the pathophysiology of the disease with the perspective of new therapeutic options.