Utility of flow cytometry immunophenotyping and DNA ploidy studies for diagnosis and characterization of blood involvement in CD4+ Sézary's syndrome.

BACKGROUND AND OBJECTIVES: The exact immunophenotypic criteria for the identification of Sézary cells in the blood are still poorly defined. DESIGN AND METHODS: We analyzed the immunophenotype and DNA cell content of blood T cells in a series of 18 consecutive cases of Sézary's syndrome (SS), 21 normal individuals and 10 patients with reactive erythroderma, and correlated them with molecular and morphological findings. RESULTS: Phenotypically abnormal CD3+/TCRalphabeta+/CD4+ T cells were found in all SS patients but in none of the reactive erythroderma cases; small diploid, or less frequently hypodiploid Sézary's cells coexisted with large nearly tetraploid Sézary's cells in some cases. The most frequent phenotypic aberrations consisted in decreased expression of CD3/TCRalphabeta (94%), CD4 (94%), CD7 (100%) and/or CD2 (83%). In addition, Sézary's cells were constantly CD28+ and CD5+ and they did not express natural-killer associated (NKa) antigens. Phenotypic heterogeneity was a common finding and phenotypic changes over time were frequently observed. In contrast to what was found in patients with reactive erythroderma, flow cytometry analysis of the T-cell receptor (TCR) repertoire revealed a major TCR-Vbeta expansion in all SS cases. INTERPRETATION AND CONCLUSIONS: The presence of CD28+/CD5+/NKa-/CD4+ T cells expressing abnormally low levels of CD3, TCRalphabeta, CD4, CD7 and/or CD2 would support the diagnosis of SS in patients with erythroderma. Further analyses on larger series of patients are necessary in order to cover less frequent phenotypic patterns, establish the preferential usage of specific TCR-Vb families and investigate the specificity of these phenotypic abnormalities for diagnosing SS.

TCRalphabeta+/CD4+ large granular lymphocytosis: a new clonal T-cell lymphoproliferative disorder.

Large granular lymphocyte (LGL) leukemia is a well-recognized disease of mature T-CD8(+) or less frequently natural killer cells; in contrast, monoclonal expansions of CD4(+) T-LGL have only been sporadically reported in the literature. In the present article we have explored throughout a period of 56 months the incidence of monoclonal expansions of CD4(+) T-LGL in a population of 2.2 million inhabitants and analyzed the immunophenotype and the pattern of cytokine production of clonal CD4(+) T cells of a series of 34 consecutive cases. Like CD8(+) T-LGL leukemias, CD4(+) T-LGL leukemia patients have an indolent disease; however, in contrast to CD8(+) T-LGL leukemias, they do not show cytopenias and autoimmune phenomena and they frequently have associated neoplasias, which is usually determining the clinical course of the disease. Monoclonal CD4(+) T-LGLshowed expression of TCRalphabeta, variable levels of CD8 (CD8(-/+dim)) and a homogeneous typical cytotoxic (granzyme B(+), CD56(+), CD57(+), CD11b(+/-)) and activated/memory T cell (CD2(+bright), CD7(-/+dim), CD11a(+bright), CD28(-), CD62L(-) HLA-DR(+)) immunophenotype. In addition, they exhibited a Th1 pattern of cytokine production [interferon-gamma(++), tumor necrosis factor-alpha(++), interleukin (IL-2)(-/+), IL-4(-), IL-10(-), IL-13(-)]. Phenotypic analysis of the TCR-Vbeta repertoire revealed large monoclonal TCR-Vbeta expansions; only a restricted number of TCR-Vbeta families were represented in the 34 cases analyzed. These findings suggest that monoclonal TCRalphabeta(+)/CD4(+)/NKa(+)/CD8(-/+dim) T-LGL represent a subgroup of monoclonal LGL lymphoproliferative disorders different from both CD8(+) T-LGL and natural killer cell-type LGL leukemias. Longer follow-up periods are necessary to determine the exact significance of this clonal disorder.

Non-cytotoxic gamma-delta peripheral T-cell lymphoma affecting the mandibular and parotidal lymph nodes and the skin.

In contrast to the majority of alphabeta peripheral T cell lymphomas (PTCL), which usually originate in lymph nodes and do not express NK-associated molecules, most gammadelta PTCL express a cytotoxic phenotype and originate at extranodal sites. We report a case of a patient with a gamma-delta PTCL who presented with large mandibular and parotidal lymphadenopathy and skin lesions. CD3(+)/TCR-Vdelta1 (+) lymphoma cells did not express the cell surface (CD11b, CD11c, CD16, CD56 and CD57) and cytoplasmic granule molecules (Perforin and Granzyme B) that usually characterize the cytotoxic T-cells, a phenotype that fulfils the criteria for diagnosis of a rare non-cytotoxic variant of a gammadelta T-cell lymphoma. "In situ" hybridization for Epstein-Barr virus-encoded RNA and latent membrane protein-1 gave negative results. The disease had an aggressive course and was resistant to chemotherapy and the patient died 4 months after diagnosis.

Guess what: Chronic 13q14.3+/CD5-/CD23+ lymphocytic leukemia in blood and t(11;14)(q13;q32)+/CD5+/CD23- mantle cell lymphoma in lymph nodes!

We report a case of a patient with two B-cell lymphoproliferative disorders: CD5(-)/CD23(+) B-cell chronic lymphocytic leukemia and CD5(+)/CD23(-) mantle cell lymphoma. These disorders were diagnosed simultaneously based on flow cytometry, immunohistochemistry, fluorescence in situ hybridization, and polymerase chain reaction-based molecular studies. The B-cell lymphocytic leukemia clone predominated in the blood and bone marrow, whereas the mantle cell clone predominated in lymph nodes.

The "ex vivo" patterns of CD2/CD7, CD57/CD11c, CD38/CD11b, CD45RA/CD45RO, and CD11a/HLA-DR expression identify acute/early and chronic/late NK-cell activation states.

To define a dynamic sequence of phenotypic changes related to early and late phases of NK-cell activation, we have analyzed by four-color flow cytometry the immunophenotype of normal blood NK-cells from 12 healthy individuals and compared it with those from 15 patients with acute viral infections and 15 patients with either chronic infections or tumors. Although a great interindividual variability was found, nonstimulated CD56(+) NK-cells, present in normal blood samples, usually were CD2(-/+lo), CD7(+hi), HLA-DR(-), CD11b(+), CD38(+), CD11a(+hi), CD45RA(+hi), and CD45RO(-), the expression of CD11c and CD57 being heterogeneous and variable. Recently activated NK-cells, herein corresponding to NK-cells from patients with acute viral infections, displayed a pattern of expression of CD2/CD7 similar to that referred to above, but they typically showed higher levels of CD11a, CD38, and HLA-DR, as well as downregulation of CD11b and CD45RA, accompanied in some cases by coexpression of CD45RO; in addition, these NK-cells were CD11c(+) and CD57(-/+lo). Late-activated NK-cells, represented by NK-cells present in patients with chronic infections and tumors, converted into a CD2(+hi)/CD7(-/+lo) immunophenotype and expressed heterogeneously low levels of CD38 and CD11b; moreover, they were CD57(+) and CD11c(-/+). At this stage, most NK-cells had already reverted into their original CD45RA(+)/CD45RO(-)/HLA-DR(-) phenotype. In summary, we show that the patterns of expression of CD2/CD7, CD57/CD11c, CD38/CD11b, CD45RA/CD45RO, and CD11a/HLA-DR may help us to define the immunophenotypic profiles associated with early and late NK-cell activation phases in 'in vivo' models.