T-cell receptor gammadelta-large granular lymphocytic leukemia associated with an aberrant phenotype and TCR-Vbeta20 clonality

Haematology Laboratory - Unit of Molecular Biology, University Hospital of Ioannina, Greece. gvarthol@cc.uoi.gr

Large granular lymphocytic (LGL) leukemia is a rare heterogenous disorder of mature lymphocytes with a characteristic morphology, multiple autoimmune disorders and indolent clinical course. Most cases exhibit a T-cell phenotype of CD3, CD8 and CD57 positivity, while the minority exhibit a CD2, CD56, and CD16 positive NK-cell phenotype. We report a case of a 71-year-old female suffering from a TCRgammadelta positive T-cell leukemia with a morphology compatible to LGL leukemia. She referred to the hospital for investigation of mild anemia, lymphocytosis, neutropenia and hyperglobulinemia. Peripheral blood and bone marrow were occupied by mature large granular lymphocytes with abundant azurophilic granules. The immunophenotype was CD3+, CD2+, CD5+, CD7+, CD4-, CD8-, CD16-, CD56-, CD57- and the Vbeta repertoire analysis showed clonal reactivity with Vbeta20 mAb. The patient was diagnosed as having T-LGL and was treated with G-CSF. So far, she experiences an indolent clinical course. To our knowledge, this is a rare case of TCRgammadelta positive T-LGL leukemia with the aberrant immunophenotype of CD3+, CD4-, CD8-, CD16-, CD56-, CD57-.