Spectrum of mutational signatures in T-cell lymphoma reveals a key role for UV radiation in cutaneous T-cell lymphoma.

T-cell non-Hodgkin's lymphomas develop following transformation of tissue resident T-cells. We performed a meta-analysis of whole exome sequencing data from 403 patients with eight subtypes of T-cell non-Hodgkin's lymphoma to identify mutational signatures and associated recurrent gene mutations. Signature 1, indicative of age-related deamination, was prevalent across all T-cell lymphomas, reflecting the derivation of these malignancies from memory T-cells. Adult T-cell leukemia-lymphoma was specifically associated with signature 17, which was found to correlate with the IRF4 K59R mutation that is exclusive to Adult T-cell leukemia-lymphoma. Signature 7, implicating UV exposure was uniquely identified in cutaneous T-cell lymphoma (CTCL), contributing 52% of the mutational burden in mycosis fungoides and 23% in Sezary syndrome. Importantly this UV signature was observed in CD4 + T-cells isolated from the blood of Sezary syndrome patients suggesting extensive re-circulation of these T-cells through skin and blood. Analysis of non-Hodgkin's T-cell lymphoma cases submitted to the national 100,000 WGS project confirmed that signature 7 was only identified in CTCL strongly implicating UV radiation in the pathogenesis of cutaneous T-cell lymphoma.

Flow cytometric evaluation of peripheral blood for suspected Sézary syndrome or mycosis fungoides: International guidelines for assay characteristics.

A peripheral blood flow cytometric assay for Sézary syndrome (SS) or circulating mycosis fungoides (MF) cells must be able to reliably identify, characterize, and enumerate T-cells with an immunophenotype that differs from non-neoplastic T-cells. Although it is also important to distinguish SS and MF from other subtypes of T-cell neoplasm, this usually requires information in addition to the immunophenotype, such as clinical and morphologic features. This article outlines the approach recommended by an international group with experience and expertise in this area. The following key points are discussed: (a) At a minimum, a flow cytometric assay for SS and MF should include the following six antibodies: CD3, CD4, CD7, CD8, CD26, and CD45. (b) An analysis template must reliably detect abnormal T-cells, even when they lack staining for CD3 or CD45, or demonstrate a phenotype that is not characteristic of normal T-cells. (c) Gating strategies to identify abnormal T-cells should be based on the identification of subsets with distinctly homogenous immunophenotypic properties that are different from those expected for normal T-cells. (d) The blood concentration of abnormal cells, based on any immunophenotypic abnormalities indicative of MF or SS, should be calculated by either direct enumeration or a dual-platform method, and reported.

Low-Dose Total Skin Electron Beam Therapy as Part of a Multimodality Regimen for Treatment of Sézary Syndrome: Clinical, Immunologic, and Molecular Analysis.

Importance: Sézary syndrome (SS) is an advanced form of cutaneous T-cell lymphoma with few long-term remissions observed. Objective: To profile 3 patients with SS who have experienced long-term remission following the addition of low-dose total skin electron beam therapy (TSEBT) to systemic regimens of extracorporeal photopheresis, bexarotene, and interferon-γ. Design, Setting, and Participants: This is a retrospective case series with additional investigations of patient-donated samples to assess therapeutic response. The study was conducted at the University of Pennsylvania Cutaneous Lymphoma Clinic and follows 3 patients with stage IVA1 CD4+ SS who presented to the clinic between November 1, 2009, and November 1, 2017, and who had a history of SS that was refractory to multimodality systemic therapy prior to receiving low-dose TSEBT. Interventions: Patients were treated in a multimodality fashion with combined extracorporeal photopheresis, bexarotene, interferon-γ, and low-dose TSEBT. Main Outcomes and Measures: To characterize treatment responses in these patients, the extent of skin disease was measured with the modified severity weighted assessment tool. Blood disease was measured with flow cytometric assessments of Sézary cell count, CD4:CD8 ratio, and high throughput sequencing of the T-cell receptors. To assess for restoration of immune function, we measured markers of immune exhaustion, including PD-1 (programmed cell death 1), TIGIT (T-cell immunoreceptor with immunoglobulin and ITIM domains), CTLA4 (cytotoxic T-lymphocyte-associated protein 4), TOX (thymocyte selection-associated high mobility group box protein), and Foxp3 (forkhead box P3) on circulating CD4 and CD8 T cells, along with production capacity of interferon-γ by lymphocytes following activation stimuli. Results: Following administration of low-dose TSEBT and maintenance of the other therapies, remissions ranged from 24 to 30 months, with complete responses in 2 patients ongoing. Markers of immune exhaustion including PD-1, TIGIT, CTLA4, TOX, and Foxp3 were significantly reduced from baseline following TSEBT, along with enhanced production capacity of interferon-γ by lymphocytes following activation stimuli. High throughput sequencing demonstrated near-complete eradication of the circulating clone among 2 of 3 patients with stable levels in 1. Conclusions and Relevance: We describe 3 patients who achieved long-term clinical and molecular remissions following low-dose TSEBT as part of a multimodality regimen for treatment of SS. As long-term remissions in SS are uncommon, this approach demonstrates promise, and clinical trials should be considered.

Determination of immunophenotypic aberrancies provides better assessment of peripheral blood involvement by mycosis fungoides/Sézary syndrome than quantification of CD26- or CD7- CD4+ T-cells.

BACKGROUND: Blood involvement by mycosis fungoides (MF)/Sézary syndrome (SS) influences prognosis and therapeutic decisions. MF/SS blood stage is currently determined by absolute CD4 + CD26- or CD4 + CD7-cell counts, which quantification method may overestimate MF/SS by including CD26- or CD7- normal CD4+ T-cells, or underestimate disease burden when MF/SS cells show incomplete loss of CD26 and/or CD7. Recently, through the standardization effort led by the International Clinical Cytometry Society (ICCS), recommendation was made to quantify MF/SS by enumerating immunophenotypically aberrant CD4+ T-cells, rather than CD26- or CD7- in isolation. METHODS: We compared these two quantitation methods in 309 MF/SS patients who had blood samples analyzed by flow cytometry immunophenotyping (FCI) over a 1-year period. RESULTS: Using the European Organization of Research and Treatment of Cancer (EORTC)/International Society for Cutaneous Lymphomas (ISCL) criteria, 221 (71.5%) patients had a blood stage corresponding to B0, 57 (18.4%) to B1, and 31 (10%) to B2. By FCI analysis, a total of 62 patients (20.0%) were found positive for MF/SS. Among EORTC B0 patients, 11/221 (5%) were positive by FCI (false negatives), and among EORTC Stage B1 patients, 35/57 (61%) were negative by FCI (false positives). Regarding patients positive for MF/SS cells by FCI, there was an overall excellent correlation (r = .999, p < .001) between the EORTC/ISCL method and FCI method; however, four (6.5%) patients would have an altered B stage between B0 and B1. CONCLUSION: The MF/SS cell quantification method using immunophenotypic aberrancies, as recommended by the ICCS, allows to distinguish MF/SS cells from background benign T-cells and enables for more accurate staging, especially among patients currently being considered to have B0 and B1 stage diseases.

High-Scatter Lymphocytes in the Blood of Erythrodermic Cutaneous T-Cell Lymphoma: Evidence for Large-Cell Transformation?

BACKGROUND: Erythrodermic cutaneous T-cell lymphoma consists of erythrodermic mycosis fungoides and Sézary syndrome. Previous studies have indicated that very large Sézary cells (> 14 µm diameter) or the presence of aneuploid cells in the blood might reflect large-cell transformation, with a corresponding poor prognosis. PATIENTS AND METHODS: A retrospective study assessed data between June 1997 and April 2002 of 32 patients with erythrodermic cutaneous T-cell lymphoma, 4 patients with leukemic mycosis fungoides, and 19 patients with nonneoplastic inflammatory conditions who were referred for evaluation of possible cutaneous T-cell lymphoma. Data were studied by 2-parameter flow cytometry gated on the lymphocyte population. RESULTS: High-scatter T lymphocytes (HSL) were detected in initial blood samples from 10 of 19 patients with Sézary syndrome, 1 of 13 patients with erythrodermic mycosis fungoides, and no patient with nonneoplastic inflammatory conditions. A significant correlation was found between HSL and very large Sézary cells and histopathologic evidence of large-cell transformation. Moreover, the presence of HSL suggests a poor prognosis even for patients with advanced disease. CONCLUSION: We propose that HSL are often large transformed neoplastic Sézary cells that may be detected in patients with clinically unapparent large-cell transformation.

Thrombospondin-1 promotes tumor progression in cutaneous T-cell lymphoma via CD47.

CD47 is highly expressed on various hematopoietic malignancies, and enables cancer cells to avoid immunosurveillance. Its ligand, thromobospondin-1 (TSP-1) is a multifunctional protein, and CD47/TSP-1 interactions promote tumor progression in various malignancies. In this study, we investigated roles of TSP-1 and CD47 in cutaneous T-cell lymphoma (CTCL). Flow cytometric analysis and immunohistochemistry showed that CTCL tumor cells and CTCL cell lines (Hut78, HH, and MyLa cells) overexpressed CD47 compared with normal CD4+ T cells. Overexpression of CD47 was partially induced by high c-Myc expression in CTCL tumor cells. TSP-1 mRNA expression levels in CTCL lesional skin were higher than those in normal skin and correlated with increased risk of disease-related death. Moreover, TSP-1 was expressed on CTCL tumor cells by immunohistochemistry. Serum soluble TSP-1 levels in patients with Sézary syndrome were significantly elevated. TSP-1 promotes proliferation and survival of CTCL tumor cells, which is inhibited by anti-CD47 neutralizing antibody or CD47 knockdown. Stimulation with TSP-1 also induces cell migration and in vivo growth. These effects were mediated by phosphorylation of ERK1/2 and AKT and expression of survivin. Collectively, our findings prompt a novel therapeutic approach to CTCL based on discovery that CD47/TSP-1 interactions play important roles in progression of CTCL.

Contribution of STAT3 and RAD23B in Primary Sézary Cells to Histone Deacetylase Inhibitor FK228 Resistance.

FK228 (romidepsin) and suberoylanilide hydroxamic acid (vorinostat) are histone deacetylase inhibitors (HDACi) approved by the US Food and Drug Administration for cutaneous T-cell lymphoma (CTCL), including the leukemic subtype Sézary syndrome. This study investigates RAD23B and STAT3 gene perturbations in a large cohort of primary Sézary cells and the effect of FK228 treatment on tyrosine phosphorylation of STAT3 (pYSTAT3) and RAD23B expression. We report RAD23B copy number variation in 10% (12/119, P ≤ 0.01) of SS patients, associated with reduced mRNA expression (P = 0.04). RAD23B knockdown in a CTCL cell line led to a reduction in FK228-induced apoptosis. Histone deacetylase inhibitor treatment significantly reduced pYSTAT3 in primary Sézary cells and was partially mediated by RAD23B. A distinct pattern of RAD23B-pYSTAT3 co-expression in primary Sézary cells was detected. Critically, Sézary cells harboring the common STAT3 Y640F variant were less sensitive to FK228-induced apoptosis and exogenous expression of STAT3 Y640F, and D661Y conferred partial resistance to STAT3 transcriptional inhibition by FK228 (P ≤ 0.0024). These findings suggest that RAD23B and STAT3 gene perturbations could reduce sensitivity to histone deacetylase inhibitors in SS patients.

Prognostic Significance of Serum Copper in Patients With Cutaneous T-cell Lymphoma.

BACKGROUND: Serum copper has been reported to be increased in various cancers, including lymphoma. The purpose of the present study was to investigate the clinical and prognostic importance of serum copper levels in patients with cutaneous T-cell lymphoma (CTCL). PATIENTS AND METHODS: Serum copper was measured in 60 men and 38 women with mycosis fungoides (MF) and 14 men and 3 women with erythrodermic CTCL (6 with Sézary syndrome) consecutively evaluated from July 1980 to June 1985. RESULTS: A greater than normal copper level was present in nearly 20% of patients and was associated with an increased risk of disease progression and shortened disease-specific survival for patients with patch or plaque phase MF, but not for those with tumor phase MF or erythrodermic CTCL. In contrast, the serum lactate dehydrogenase level and neutrophil/lymphocyte ratio were not significantly associated with prognosis in our patient cohort. CONCLUSION: The reason for the association between the high serum copper levels and adverse prognosis is unknown. We hypothesized that interleukin-6 is secreted primarily by non-neoplastic cells at MF skin sites, leading to release of copper by the liver. Local production of interleukin-6 at the lesion sites might conceivably also promote neoplastic cell progression by stimulation of the STAT3 pathway. Further studies on the relationship between activated tumor-associated macrophages, serum copper levels, interleukin-6, or C-reactive protein and prognosis might be informative.

Infectious events and associated risk factors in mycosis fungoides/Sézary syndrome: a retrospective cohort study.

BACKGROUND: Infections are one of the major causes of death in patients with advanced-stage mycosis fungoides (MF) or Sézary syndrome (SS). However, few recent data are available on the characteristics and risk factors of these infectious events. OBJECTIVES: To describe infectious events occurring in a cohort of patients with MF/SS, and to identify associated clinical and biological risk factors. METHODS: A retrospective cohort study was performed to investigate infectious events and associated factors in patients diagnosed with MF (stage IB and beyond) or SS followed from May 2011 to May 2016 at the University Hospital of Bordeaux, France. RESULTS: Seventy-one patients with complete follow-up were included. Eighty infectious events were recorded in 40 patients, including 28 skin and soft tissue infections and 25 cases of pneumonia. Opportunistic infections, which are usually associated with depleted cell-mediated immunity, were scarce (9%). In multivariate analysis, cardiac, renal or lung comorbidities [odds ratio (OR) 7·2, 95% confidence interval (CI) 3·3-15·9; P = 0·002], SS (OR 8·8, 95% CI 7·7-10·2; P = 0·037) and lymphocyte count < 0·5 × 109 cells L-1 (OR 6·4, 95% CI 1·5-27·4; P = 0·004) were significantly associated with a higher risk of infection. CONCLUSIONS: Opportunistic germs were rarely recorded, but their incidence was probably prevented by adequate prophylaxis (ongoing in 28% of patients). As in patients living with AIDS, pneumonias were frequent. On the other hand, bacterial cutaneous infections represent a specific pattern in patients with MF/SS. Patients with chronic organ failure, lymphocytopenia and SS should be considered as being at high risk for infectious events. Pneumococcal vaccination should be systematically recommended, and prophylaxis with co-trimoxazole and valaciclovir when the CD4 count is < 0·2 × 109 cells L-1 .

Blood classification and blood response criteria in mycosis fungoides and Sézary syndrome using flow cytometry: recommendations from the EORTC cutaneous lymphoma task force.

Our current mycosis fungoides (MF) and Sézary Syndrome (SS) staging system includes blood-classification from B0-B2 for patch/plaque/tumour or erythroderma based on manual Sézary counts but results from our EORTC survey confirm these are rarely performed in patch/plaque/tumour MF, and there is a trend towards using flow cytometry to measure blood-class. Accurately assigning blood-class effects overall stage and the 'global response' used to measure treatment responses in MF/SS and hence impacts management. The EORTC Cutaneous Lymphoma Task Force Committee have reviewed the literature and held a Workshop (June 2017) to agree a definition of blood-class according to flow cytometry. No large study comparing blood-class as defined by Sézary count with flow cytometry has been performed in MF/SS. The definition of blood-class by flow cytometry varies between publications. Low-level blood involvement occurs in patch/plaque/tumour much less than erythroderma (p < 0.001). The prognostic relevance of blood involvement (B1 or B2) in patch/plaque/tumour is not known. Studies have not shown a statistically worse difference in prognosis in erythrodermic MF patients with low-level blood involvement (IIIB) versus those without (IIIA), but Sezary patients who by definition have a leukaemic blood picture (staged IVA1 or higher) have a worse prognosis. For consistency flow, definition for blood-class must be an objective measurement. We propose absolute counts of either CD4+CD7-or CD4+CD26-where B0<250/µL, B1 = 250/µl-<1000/µL and B2≥1000/µL plus a T-cell blood clone. Fluctuations between B0 and B1 should not be considered in the treatment response criteria until further prognostic information is known.

Increased interleukin-36γ expression in skin and sera of patients with atopic dermatitis and mycosis fungoides/Sézary syndrome.

Interleukin (IL)-36γ is expressed by keratinocytes and functions as a key initiator of inflammation in the skin. IL-36γ expression is enhanced by tumor necrosis factor-α and IL-17A, having a strong association with psoriasis. In this study, we examined the role of IL-36γ in atopic dermatitis (AD) and mycosis fungoides (MF)/Sézary syndrome (SS). Serum levels of IL-36γ in AD patients and MF/SS patients were elevated compared with those of healthy controls. Importantly, serum IL-36γ levels in AD patients positively correlated with Eczema Area and Severity Index and those of MF/SS patients positively correlated with serum soluble IL-2 receptor levels. IL-36γ mRNA levels in AD skin and MF/SS skin were significantly higher than those of normal skin. IL-36γ mRNA levels in MF/SS skin positively correlated with IL-17A mRNA levels. Immunohistochemical staining revealed that IL-36γ was highly expressed in keratinocytes in lesional skin of AD and MF/SS. Taken together, our study demonstrated that IL-36γ expression was increased in sera and skin of patients with AD and MF/SS as was reported in psoriatic patients.

CD4+CD26- lymphocytes are useful to assess blood involvement and define B ratings in cutaneous T cell lymphoma.

Bernengo et al. reported that >30% CD4+CD26- lymphocytes detect blood involvement in patients with mycosis fungoides (MF) and Sézary syndrome. In addition, the ISCL/EORTC suggested that this threshold might serve as a criterion for the B2 blood rating for staging. In this manuscript, we report our experience with measurement of CD4+CD26- and CD4+CD7- cells, Sézary cell counts, and aberrant T cells with diminished expression of CD2, CD3, or CD5 antigens. CD4+CD26- ≥30% occurred in 15 of 373 (4.0%) patients with MF, 33 of 47 (70%) patients with erythrodermic cutaneous T cell lymphoma (ECTCL) and 2 of 54 (4%) patients with inflammatory skin diseases. CD4+CD26- measurements provided a more reliable assessment of neoplastic cell numbers in the blood than Sézary cell or CD4+CD7- percentages. CD4+CD26- measurements may be used to define B ratings for staging with B2 defined as CD4+CD26- ≥ 1000/µL, plus clonality or phenotypically abnormal cells.