The relevance of the CD4+ CD26- subset in the identification of circulating Sézary cells

BACKGROUND: The lack of specific markers for the phenotyping of circulating neoplastic T cells in Sézary syndrome (SS) patients makes it difficult both to ascertain the presence of clonal cells and to quantify the tumour burden in the peripheral blood. In previous reports we showed that the lack of CD26 (dipeptidyl-aminopeptidase IV) is a characteristic feature of circulating Sézary cells (SC). OBJECTIVES: The purpose of this study was to ascertain, by means of high-resolution two-, three- or four-parameter flow cytometry, the relationship between CD26 expression on peripheral blood lymphocytes and peripheral blood involvement in cutaneous T-cell lymphoma patients and to assess its significance in SS diagnosis. METHODS: The patient population included 52 SS patients, 151 mycosis fungoides (MF) patients at different clinical stages (including 14 with blood involvement, B1-MF), 88 patients with erythrodermic inflammatory skin diseases (EISD) and 72 healthy donors (HD). CD26+ values were available in all cases, whereas CD4+ CD26- level measurement was performed in 23 SS, 141 MF, 71 EISD and 72 HD. RESULTS: CD4+ CD26- percentage values were higher than 30% in all but one B1-MF and higher than 40% in all SS cases, whereas HD, EISD and B0-MF patient values were always lower than 30%. A statistically significant difference was found in both CD26- and CD4+ CD26- percentage and absolute values between SS and HD, EISD and B0-MF patients. The CD26- and CD4+ CD26- percentage values (but not the absolute values) were significantly higher in B1-MF compared with HD, EISD and B0-MF patients (P < 0.001). Moreover, CD26- absolute values and CD4+ CD26- percentage and absolute values were significantly higher in SS than in B1-MF (P < 0.001). A statistically significant direct relationship was found between CD4+ CD26- percentage values and the percentage of circulating SC within the lymphoid population in SS and B1-MF (r = 0.77; P < 0.001). The lack of CD26 was confirmed on phenotypically clonal cells in patients with an expanded circulating TCRvbeta population or a T-cell antigen loss. Sorted CD4+ CD26- cells from both SS patients and HD showed the characteristic cerebriform nuclei of SC. CONCLUSIONS: We feel that a CD4+ CD26- percentage value higher than 30% of peripheral blood lymphocytes could correctly identify the presence of peripheral blood involvement in SS and MF patients.     

CD4(+)CD7(-) T cells compose the dominant T-cell clone in the peripheral blood of patients with Sézary syndrome

BACKGROUND: Absence of CD7 antigen expression in T cells defines a subset of normal CD4(+) CD45RO(+) CD45RA(-) memory cells and is furthermore observed in Sézary syndrome (SS). OBJECTIVE: Our purpose was to identify circulating T-cell clones in patients with SS and to elucidate whether the dominant T-cell clones express the CD7 antigen. METHODS: Peripheral blood lymphocytes of patients with SS were analyzed by two-color flow cytometry using antibodies to the V beta region of the T cell receptor (TCR) in combination with an antibody to CD7. In addition, T cells were analyzed for TCR-gamma gene rearrangement by polymerase chain reaction (PCR) techniques. RESULTS: Clonal T-cell expansion was detected in 7 patients with SS by immunostaining of the TCR V beta regions. PCR analysis confirmed the presence of dominant T cell clones. Double-immunostaining revealed that in each case cells of the clonal V beta TCR rearrangement homogeneously express the CD4(+)CD7(-) phenotype. Furthermore, CD4(+)CD7(-) cells express the CD15s antigen but lack expression of CD26 and CD49d. CONCLUSION: Expansion of clonal T cells strongly correlates with the expansion of CD4(+)CD7(-) T cells in 7 tested patients with SS. This supports our model that a subset of late differentiated, normal CD4(+)CD7(-) memory T cells may represent the physiologic counterpart of Sézary cells. Monitoring of circulating T cells with the CD4(+)CD7(-)CD15s(+)CD26(-)CD49d(-) phenotype proved to be useful for the identification of clonal T cells in patients with SS.     

Circulating CD4+CD7- lymphocyte burden and rapidity of response: predictors of outcome in the treatment of Sézary syndrome and erythrodermic mycosis fungoides with extracorporeal photopheresis

BACKGROUND: Extracorporeal photopheresis (ECP) is an effective treatment for cutaneous T-cell lymphoma. Controversy has arisen regarding its ability to improve survival rates in Sézary syndrome (SS). We describe our experience with ECP in the treatment of SS and erythrodermic mycosis fungoides, with particular emphasis on early predictors of long-term outcome. OBSERVATIONS: We included 17 patients (15 with SS and 2 with erythrodermic mycosis fungoides) who received ECP as initial treatment. Four of these patients were moribund on presentation (Eastern Cooperative Oncology Group Performance Status score, 4) and underwent only 1 to 2 cycles of ECP. The median survival was 56 months for the 11 patients with SS and an Eastern Cooperative Oncology Group Performance Status score of less than 4. If all 15 patients with SS are considered, median survival was 34 months. Response after 5 months of ECP correlated with long-term survival. A low number (<6.0 x10(3)/ micro L) of circulating CD4(+)CD7(-) lymphocytes correlated with response after 5 months of ECP. CONCLUSIONS: Extracorporeal photopheresis is a safe, effective, and well-tolerated treatment for erythrodermic mycosis fungoides and SS. Low numbers of CD4(+)CD7(-) cells in the circulation and a positive response after 5 months of therapy predicted long-term survival. Moribund patients are much less likely to benefit from ECP.     

Levels of TGF-β<Subscript>1</Subscript> in serum and culture supernatants of CD4<Superscript>+</Superscript>CD25<Superscript>+</Superscript> T cells from patients with non-segmental vitiligo

Compelling evidences support an autoimmune basis of non-segmental vitiligo, and dysregulation of CD4⁺CD25⁺ regulatory T cell (Treg) is assumed to contribute to the pathogenesis of vitiligo. Serum levels of transforming growth factor-β (TGF-β), an important immunoregulatory cytokine produced by Treg cells, has been reported significantly decreased in patients with vitiligo. However, relation between the decrease in TGF-β and the dysfunction of Treg cells in pathogenesis of vitiligo was still undemonstrated. To further reveal the role of TGF-β in vitiligo, 46 patients with non-segmental vitiligo and 25 age- and sex-matched healthy control subjects were enrolled in the study. CD4⁺CD25⁺ T cells isolated from peripheral venous blood with a CD4⁺CD25⁺ regulatory T cell isolation kit were cultured with or without anti-CD3 mAbs and anti-CD28 mAbs for 4 days. The TGF-β1 levels in serum and culture supernatants were detected by enzyme-linked immunosorbent assay in both groups. We have found that the TGF-β1 levels both in serum and culture supernatants in the presence of anti-CD3 mAbs and anti-CD28 mAbs were decreased in the active vitiligo group when compared with the control group or stable vitiligo group, and were negatively correlated with the percentage of involved body area. These results suggested that TGF-β may play a role in the pathogenesis of non-segmental vitiligo related to the suppressive function of Tregs.     

Hepatitis C virus (HCV) in cryoglobulinaemic leukocytoclastic vasculitis (LCV): could the presence of HCV in skin lesions be related to T CD8+ lymphocytes,HLA-DR and ICAM-1 expression?

An association between mixed cryoglobulinaemia (MC) and hepatotropic viruses, chiefly hepatitis C virus (HCV), has been widely reported. The presence of HCV genomic sequences or HCV-related viral proteins in the serum, purified cryoglobulins, peripheral blood mononuclear cells and into several tissues has suggested an important triggering role for HCV in MC patients. However, only few reports investigated the presence of HCV in cutaneous vasculitis and its potential pathogenetic role. Biopsies of cutaneous purpuric lesions from 5 MC female patients (aged from 40 to 80 years) were carried out for virological and histopathological evaluation. A leukocytoclastic vasculitis pattern was found in 4/5 subjects, while the presence of HCV RNA was detected in 3/5. In only 3 cases biopsy specimens were sufficient for immunohistochemical and direct immunofluorescence (DIF) studies. Immunohistochemical evaluation was performed by means of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP) immune-complexes. In the same skin specimen APAAP and DIF findings were compared with the presence/absence of HCV genomic sequences (PCR technique). In 1 MC patient, the detection of HCV-RNA was associated to a prevalent CD8+ T suppressor pattern with a perivascular and subjunctional distribution as well as an intense expression of second class (HLA-DR) and intercellular adhesion (ICAM-1) molecules on basal keratinocytes, endothelial cells and perivascular infiltrate. These findings suggest a marked inflammatory activation that spreads from endothelial cells to keratinocytes and Langerhans cells. In the 2 HCV-RNA negative specimens the scanty immunopathological staining could indicate a residual activity due to the previous inflammatory event triggered by cryoglobulins. The deposition of circulating HCV-containing immune complexes (CIC) in the skin could be the initial pathogenic event for cryoglobulinemic vasculitis; subsequently CIC could spread from the vascular bed to the perivascular tissue and then could be very rapidly eliminated. If confirmed in larger patients' series these findings could definitely demonstrate a direct role of HCV in the pathogenesis of cryoglobulinemic vasculitis.