T-cell prolymphocytic leukaemia: Spontaneous immunophenotypical switch from CD4 to CD8 expression

Annals of Hematology (Impact Factor: 2.63). 04/2011; 90(4):479-81. DOI: 10.1007/s00277-010-1026-x
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    • "Once expressing CD4 or CD8, the T-cells are committed to distinct functions, helper or cytotoxic T-cells, respectively, and the commitment is inconvertible and irreversible, as a general rule of hematopoietic cell differentiation [14]. Although aberrant expression or deletion of antigens is often observed in lymphoid neoplasms, subset switching is a rare phenomenon in T-cell neoplasia , only being documented in one case with a phenotypic shift from CD4 to CD8 [19]. To the best of our knowledge, a conversion of CD8 to CD4 restriction in T-cell lymphomas/leukemias has never been described in the English literature. "
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    ABSTRACT: A 55-year-old female with T-cell large granular lymphocytic leukemia (T-LGL) (CD8 + ) was initially treated with anti-thymocyte globulin and then cyclosporine due to anemia/neutropenia. While the severity of cytopenia varied with the therapy, the T-LGL persisted. Eight years after the initial diagnosis, she developed lymphadenopathy and hepatosplenomegaly. A complete blood cell count revealed leukocytosis, anemia and thrombocytopenia with ∼80% lymphocytes. In contrast to the LGL cells, the blood lymphocytes at this time were medium-large in size and had oval/irregular nuclei, condensed chromatin, indistinct nucleoli and a moderate amount of basophilic cytoplasm, many with elongated vacuoles, and some with cytoplasmic projections. The abnormal lymphocytes comprised ∼30% of the bone marrow cellularity with interstitial infiltrates/aggregates. Immunophenotypic analyses demonstrated a T-cell neoplasm with features suggestive of T-cell prolymphocytic leukemia (T-PLL) (CD4 + ). Cytogenetic analysis revealed a novel clone with complex abnormalities. PCR-based TRG gene rearrangement studies detected a clonal amplicon distinct from that of the preexisting T-LGL. Because of the chronological sequence of the two T-cell neoplasms, this case was initially considered an aggressive transformation of T-LGL. However, this was ultimately excluded by a discordant CD4-subset restriction and the presence of a distinct clonal identity. While these two T-cell neoplasms may have intrinsic connections, the underlying pathogenesis remains to be investigated.
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    ABSTRACT: Primary cutaneous T-cell lymphomas (CTCL) comprise a heterogeneous group of neoplasms with diverse clinical behavior. Mycosis fungoides (MF) is the most common type of CTCL. Immunophenotypical shift during progression of the disease is a rare event and its significance is unknown. We present three primary CTCL cases that showed an immunophenotypical shift and poor prognosis. Conventional hematoxylin/eosin and immunohistochemical-stained sections were examined in all the cases. Molecular analysis for rearrangement of the T-cell receptor (TCR) gene was performed in two cases. One case was classified as MF, while the other two lacked epidermotropism, and were considered primary cutaneous peripheral T-cell lymphoma (PTCL), NOS. Two cases were CD3+/CD4+ and one case was CD3+/CD8+ at diagnosis. The first two patients suffered many relapses and eventually, new CTCL lesions with a CD3+/CD8+ phenotype were observed. Both cases revealed identical clonal TCR rearrangements on the initial and late lesions, supporting the interpretation of a single clonal proliferation with different phenotypes. The third case progressed with skin recurrences and pulmonary lesions with a predominant CD3+/CD4+/CD8- phenotype. All cases manifested poor prognosis and two patients died of lymphoma. Immunophenotypical shift between CD4 and CD8 in CTCL seems to be a rare phenomenon that may be associated with disease progression.
    Full-text · Article · Oct 2013 · Journal of Cutaneous Pathology
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    ABSTRACT: Objectives: To review clinical data, cytogenetic findings, and flow cytometric analysis in 20 patients with T-cell prolymphocytic leukemia (T-PLL), a rare, aggressive, mature T-cell leukemia with poor prognosis and short survival. Methods: Using multiparameter flow cytometry with a large combination of antibodies, we summarize the immunophenotypic features of T-PLL, including unusual immunophenotypic variants, and illustrate immunophenotypic clues that may help distinguish this entity from other T-cell malignancies. Results: By flow cytometry, T-PLL is characterized by a postthymic mature T-cell immunophenotype with a variety of abnormalities that usually allow distinction from other mature T-cell leukemias. Conclusions: Although definitive diagnosis of T-PLL requires a systemic approach with integration of clinical data, morphology, immunophenotype, cytogenetics/fluorescence in situ hybridization, and molecular features, our results indicate immunophenotyping by multiparameter flow cytometry greatly facilitates diagnosis and assists with subclassification of this mature T-cell leukemia.
    No preview · Article · Nov 2013 · American Journal of Clinical Pathology
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