T-Cell Large Granular Lymphocyte Leukemias Have Multiple Phenotypic Abnormalities Involving Pan–T-Cell Antigens and Receptors for MHC Molecules

Abstract

T-cell large granular lymphocyte (T-LGL) leukemias represent monoclonal T-cell expansions that express CD16, CD56, or CD57 and cause cytopenias. The identification of T-LGL leukemias can be difficult because reactive T-LGL cells also can express CD16, CD56, and CD57, and many leukemia cases show only mild lymphocytoses. In this study, 23 T-LGL leukemia cases were analyzed by 3- and 4-color flow cytometry to identify markers that could aid in discriminating leukemic from normal T-LGL. In most cases (18/23), abnormalities (bright, dim, or negative expression) of 2 or more pan-T-cell antigens were identified, with all cases showing abnormal CD5 levels. Abnormal expression of CD94 was identified in 22 of 23 cases, and 15 of 21 cases also showed abnormal expression of class 1 MHC receptor molecules identified by antibodies against CD158a, CD158b, CD158e, CD158i, CD158k, and CD94. These studies help define abnormal phenotypic features typical of T-LGL leukemia that may have important diagnostic value.

Deciphering the killer‐cell immunoglobulin‐like receptor system at super‐resolution for natural killer and T‐cell biology

“…For instance, in NK and T‐cell large granular lymphocytosis lymphocytes often express activating or inhibitory KIRs in a clonal manner 225, 226, 227, 228. Patients with Sezary syndrome typically display CD4 + T cells expressing KIR3DL2, which might contribute to disease onset 228, 229.…”

CD56 Negative Aggressive T Cell Large Granular Lymphocytic Leukemia

“…Leukemic proliferation has an aberrant immunophenotype.CD5 and CD7 are most commonly downregulated antigens [11]. NK cell associated antigens like CD16 and CD57 are expressed in 80 and 100 % of the cases respectively.…”

Refining the diagnosis of T-cell large granular lymphocytic leukemia by combining distinct patterns of antigen expression with T-cell clonality studies

“…10,18 Others have detailed specific bone marrow immunohistochemical criteria for defining cases of T-LGL leukemia with detailed statistical analyses. 8 However, a statistically powered study of cases of LGL expansions to determine the significance of variations in antigen expression by flow cytometry has not been performed to date.…”

“…Although prior studies have demonstrated distinct histologic features associated with T-LGL leukemia in the marrow 8 as well as novel TCR antibodies that can be used to define LGL leukemia, 9 relatively few studies have attempted to comprehensively and statistically define the specifics of non-TCR antigen expression by flow cytometry. 10,11 As such, we performed a detailed retrospective review of 85 patients, at Stanford University Medical Center, with LGL expansions in their peripheral blood in an attempt to determine distinct flow cytometry patterns that are associated with T-LGL leukemia.…”