Aberrant expression of adhesion molecules by Sézary cells: functional consequences under physiologic shear stress conditions

Differential CCR4 expression and function in cutaneous T-cell lymphoma cell lines

Cutaneous T cell lymphoma (CTCL) is a clonal epidermotropic malignancy of memory T cells primarily involving the skin. However, the mechanisms governing migration of CTCL cells have not been fully clarified. It has been shown that certain chemokine receptors are upregulated in CTCL cells, but it remains unanswered whether these chemokine receptors play a critical role in the migration dynamics of CTCL. Using cell lines originally derived from patients with different subtypes of CTCL, we have shown higher CCR4 expression in the line derived from the mycosis fungoides (MJ), compared with the line derived from Sezary syndrome (Hut78). In specific responses to CCL22 (a CCR4 ligand) treatments, MJ cells showed significant chemotactic migration, enhanced activation and adhesion of certain integrins (CD49d and CD29) in vitro, while the control cells (Hut78, CD4+CD45RO+ memory T cells, and Jurkat cells) did not. Furthermore, compared with Hut78 cells, MJ cells manifested significantly more transendothelial migration in responses to treatments with either CCL22 or conditioned medium from dendritic cells in vitro. These results provide further dynamic evidence, in line with the multistep cascade paradigm for leukocyte transendothelial migration, to support a critical role for CCR4 in CTCL migration.

Chemokine receptor expression by leukemic T cells of cutaneous T-cell lymphoma: clinical and histopathological correlations

Chemokine receptors expressed by normal and neoplastic lymphocytes provide an important mechanism for cells to traffic into the skin and skin-associated lymph nodes. The goal of this study was to correlate chemokine receptor and CD62L expression by circulating neoplastic T cells with the clinical and pathological findings of the leukemic phase of cutaneous T-cell lymphoma, primarily Sézary syndrome (SS). Chemokine receptor mRNA transcripts were found in the majority of leukemic cells for CCR1, CCR4, CCR7, CCR10, CXCR3, and CD62L and in 20-50% of the samples for CXCR5. In patients with SS, relatively high expression levels of CCR7 and CCR10 by circulating neoplastic T cells correlated with epidermotropism, CXCR5 expression correlated with density of the dermal infiltrate, and CD62L correlated with extent of lymphadenopathy. Of note, CXCR5 expression and a dense dermal infiltrate correlated with a poor prognosis. The chemokine receptor profile supports the concept that neoplastic T cells are central memory T cells, and that CCR10 and CD62L play a fundamental role respectively in epidermotropism and lymphadenopathy that is observed in SS.

Aberrant expression of the tyrosine kinase receptor EphA4 and the transcription factor twist in Sézary syndrome identified by gene expression analysis

Sézary syndrome (Sz) is a malignancy of CD4+ memory skin-homing T cells and presents with erythroderma, lymphadenopathy, and peripheral blood involvement. To gain more insight into the molecular features of Sz, oligonucleotide array analysis was performed comparing gene expression patterns of CD4+ T cells from peripheral blood of patients with Sz with those of patients with erythroderma secondary to dermatitis and healthy controls. Using unsupervised hierarchical clustering gene, expression patterns of T cells from patients with Sz were classified separately from those of benign T cells. One hundred twenty-three genes were identified as significantly differentially expressed and had an average fold change exceeding 2. T cells from patients with Sz demonstrated decreased expression of the following hematopoietic malignancy-linked tumor suppressor genes: TGF-beta receptor II, Mxi1, Riz1, CREB-binding protein, BCL11a, STAT4, and Forkhead Box O1A. Moreover, the tyrosine kinase receptor EphA4 and the potentially oncogenic transcription factor Twist were highly and selectively expressed in T cells of patients with Sz. High expression of EphA4 and Twist was also observed in lesional skin biopsy specimens of a subset of patients with cutaneous T cell lymphomas related to Sz, whereas their expression was nearly undetectable in benign T cells or in skin lesions of patients with inflammatory dermatoses. Detection of EphA4 and Twist may be used in the molecular diagnosis of Sz and related cutaneous T-cell lymphomas. Furthermore, the membrane-bound EphA4 receptor may serve as a target for directed therapeutic intervention.

The molecular basis of lymphocyte recruitment to the skin: clues for pathogenesis and selective therapies of inflammatory disorders

Spatial compartmentalization and tissue-selective localization of T lymphocytes to the skin are crucial for immune surveillance and the pathogenesis of various disorders including common inflammatory diseases such as atopic dermatitis or psoriasis, but also malignancies such as cutaneous T cell lymphomas. Cutaneous recruitment of lymphocytes is a highly complex process that involves extravasation, migration through the dermal connective tissue, and eventually, localization to the epidermis. An intertwined network of cytokines and chemokines provides the road signs for leukocyte migration, while various adhesion receptors orchestrate the dynamic events of cell-cell and cell-substrate interactions resulting in cutaneous localization of T cells. Selectively targeting the functions of molecules involved in this interplay promises exciting new therapeutic options for treating inflammatory skin disorders.

Functional expression of the eotaxin receptor CCR3 in CD30+ cutaneous T-cell lymphoma

Little is known about mechanisms involved in skin-specific homing of cutaneous T-cell lymphoma (CTCL). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. We investigated tissue samples and tumor cell suspensions of patients with CD30(+) CTCL (n = 8) and CD30(-) CTCL (mycosis fungoides, n = 6; Sézary syndrome, n = 6) for expression of the chemokine receptors CCR3, CCR4, and CCR8 and the CCR3 ligands eotaxin/CCL11, monocyte chemoattractant protein 3 (MCP-3)/CCL7, and RANTES (regulated on activation, normal T expressed and secreted)/CCL5. Of 8 CD30(+) CTCLs, 7 expressed CCR3, 4 CCR4, and none CCR8. CCR3 expression was not found in skin tissue samples from 12 CD30(-) CTCLs. Coexpression of CCR3 and CD30 was demonstrated by flow cytometry in tumor cell suspensions. Internalization experiments demonstrated functionality of CCR3 expressed by freshly isolated tumor cells. Actin polymerization as well as migration in response to eotaxin was demonstrated in a CD30(+) cutaneous lymphoma cell line. CCR3 ligand eotaxin/CCL11 was detected in lesional skin of CD30(+) CTCL by immunohistochemistry, preferentially in tumor cells. Eotaxin/CCL11 expression in tumor cells was confirmed by intracellular immunofluorescence. Analysis of cytokine expression pattern of CCR3-bearing infiltrating cells showed a predominance of interleukin-4 (IL-4) but not interferon-gamma (IFN-gamma) protein expression,1 consistent with a T-helper 2 (Th-2) profile. These results suggest that expression of CCR3 and its ligand eotaxin/CCL11 plays a role in the recruitment and retention of CD30(+) malignant T cells to the skin.

Peripheral blood manifestations of lymphoma and solid tumors

Although the peripheral blood film has limited use in this age of technologic testing, most new tests are ancillary and cannot be interpreted accurately without examining the peripheral blood film. The peripheral smear plays a critical role in the diagnosis and management of many lymphoproliferative disorders, although playing more of a general function in nonlymphoid malignancies to evaluate cytopenias.