Sézary syndrome (SS) is an aggressive cutaneous T-cell lymphoma, characterized by erythroderma, lymphadenopathy and circulating malignant CD4+ T cells. Despite therapeutic advances, SS remains an incurable disease. Early diagnosis is therefore essential for timely therapeutic intervention; however, reliable biomarkers to identify circulating SS cells are still lacking. Recent studies highlighted dysregulation of the ectoenzymes CD39, CD73 and CD38 in SS, suggesting a potential role for these molecules in the disease. Thirty-three patients were enrolled in this study, and CD39/CD73/CD38 expression was analysed on circulating CD4+ T cells by multiparametric flow cytometry, enabling discrimination between malignant and non-malignant T-cell subsets. SS cells exhibited marked CD39 or CD73 overexpression together with consistent CD38 downregulation, a pattern also confirmed in paired skin biopsy, whereas non-malignant CD4+ T cells largely maintained expression profiles comparable to healthy controls. Genotyping further identified ENTPD1 single nucleotide polymorphism rs10748643 as a contributor to CD39 dysregulation, defining a CD39-permissive subgroup characterized by CD39+ SS cells. In conclusion, the combined overexpression of CD39 or CD73 and loss of CD38 defines a distinct tumour-restricted immunophenotypic signature in SS. Integrating these ectoenzymes into flow cytometry panels may improve detection of malignant CD4+ T cells across blood and skin, eventually strengthening diagnostic accuracy.

Cutaneous T-cell lymphoma (CTCL), characterized by malignant T-cell proliferation primarily in the skin, includes subtypes such as mycosis fungoides (MF) and Sézary syndrome (SS). The tumor microenvironment (TME) is central to their pathogenesis, with flow cytometry and histology being the gold standards for detecting malignant T cells within the TME. Alongside emerging molecular markers, particularly clonality analysis, these tools are indispensable for accurate diagnosis and treatment planning. Of note, adenosine signaling within the TME has been shown to suppress immune responses, affecting various cell types. The expression of CD39, CD73, and CD38, enzymes involved in adenosine production, can be elevated in MF and SS, contributing to immune suppression. Conversely, the expression of CD26, part of the adenosine deaminase/CD26 complex, that degrades adenosine, is often lost by circulating tumoral cells. Flow cytometry has demonstrated increased levels of CD39 and CD73 on Sézary cells, correlating with disease progression and prognosis, while CD38 shows a variable expression, with its prognostic significance remaining under investigation. Understanding these markers’ roles in the complexity of TME-mediated immune evasion mechanisms might enhance diagnostic precision and offer new therapeutic targets in CTCL.

Abstract Background The introduction of adjuvant therapies for patients with resected cutaneous melanoma (CM) has increased the need for sensitive biomarkers for risk stratification and disease monitoring. This study aims to investigate the utility of circulating tumor DNA (ctDNA) assessment in predicting and reflecting disease status during adjuvant therapy. Methods We enrolled 32 patients with resected BRAF-mutated stage III CM receiving adjuvant targeted therapy or immunotherapy. Plasma samples of patients were collected at the baseline (treatment initiation) and during the therapy, and BRAF-mutated ctDNA was quantified by droplet digital PCR (ddPCR). Results Baseline ctDNA was detected in 11/32 (34.4%) patients and predicted postoperative high risk of relapse [HR 3.79, 95% CI 1.20–12.00, p = 0.023]. The three-year overall survival (OS) rate was 54.6% (95% CI 22.9–77.9) versus 95% (95% CI 69.5–99.3) in ctDNA-positive and negative groups, respectively, with significantly worse OS for ctDNA-positive patients [HR 7.92, 95% CI 1.56–40.36, p = 0.013]. Among the baseline ctDNA-positive group (high-risk patients), longitudinal ctDNA detection during adjuvant therapy reflected the clinical outcomes. Only non-relapsing patients cleared their plasma ctDNA by the end of the treatment, while persistent ctDNA detection provided early evidence of disease recurrence. Conclusions ctDNA detection shows promising results in the post-operative setting for identifying cutaneous melanoma patients at the highest risk of relapse and for real-time monitoring of patients’ clinical status and treatment response.

Objective The etiopathogenesis of systemic sclerosis (SSc) is unknown. Platelet‐derived growth factor receptors (PDGFRs) are overexpressed in patients with SSc. Because PDGFRα is targeted by the adeno‐associated virus type 5 (AAV5), we investigated whether AAV5 forms a complex with PDGFRα exposing epitopes that may induce the immune responses to the virus–PDGFRα complex. Methods The binding of monomeric human PDGFRα to the AAV5 capsid was analyzed by in silico molecular docking, surface plasmon resonance (SPR), and genome editing of the PDGFRα locus. AAV5 was detected in SSc lungs by in situ hybridization, immunohistochemistry, confocal microscopy, and molecular analysis of bronchoalveolar lavage (BAL) fluid. Immune responses to AAV5 and PDGFRα were evaluated by SPR using SSc monoclonal anti‐PDGFRα antibodies and immunoaffinity‐purified anti‐PDGFRα antibodies from sera of patients with SSc. Results AAV5 was detected in the BAL fluid of 41 of 66 patients with SSc with interstitial lung disease (62.1%) and in 17 of 66 controls (25.75%) ( P < 0.001). In SSc lungs, AAV5 localized in type II pneumocytes and in interstitial cells. A molecular complex formed of spatially contiguous epitopes of the AAV5 capsid and of PDGFRα was identified and characterized. In silico molecular docking analysis and binding to the agonistic anti‐PDGFRα antibodies identified spatially contiguous epitopes derived from PDGFRα and AAV5 that interacted with SSc agonistic antibodies to PDGFRα. These peptides were also able to bind total IgG isolated from patients with SSc, not from healthy controls. Conclusion These data link AVV5 with the immune reactivity to endogenous antigens in SSc and provide a novel element in the pathogenesis of SSc. image

Abstract We demonstrated aberrant expression of CD39 or CD73 and low expression of CD38 in circulating and skin-homing CD4+ T cells in patients with Sézary syndrome (SS), an erythrodermic cutaneous T-cell lymphoma (CTCL) with a leukemic component. The anti-CCR4 monoclonal antibody Mogamulizumab (Moga) has been shown to increase progression-free survival in patients with advanced SS. Here, we longitudinally explored the modulation of the expression of CD39, CD73 and CD38 in circulating CD4+ T cells from SS patients under treatment with Moga. Eight patients with relapsed/refractory SS were included in the study and prospectively followed up for two years (median duration of treatment 9,5 months, range 5-28 months). Seven out of eight (87,5%) patients showed early complete response in the blood and partial (5/7, 71,4%) or near complete response (2/7, 28,6%) in the skin. One patient (12,5%) showed no blood or skin response to the treatment. Flow cytometry analysis highlighted that the clinical response was accompanied by a rapid and remarkable increase in CD38 expression in the residual circulating CD4+ T cells, as well as in CD8+ T cells. Moreover, in six patients carrying the homozygous G/G or heterozygous A/G ENTPD1 SNP rs10748643 genotypes, permissive to CD39 overexpression in T cells, the increased CD38 expression was paralleled by rapid reduction/loss of CD39. Notably, in one patient carrying the A/A genotype, characterized by low CD39 and high CD73 expression at the baseline, response to treatment was characterized by reduction of CD73 expression. The only one patient with A/A genotype who didn’t respond to Moga showed no modulation of CD38 or CD39 expression, while CD73 expression increased. Noteworthy, Moga increases the expression of CD38 in responding patients, and influences the expression of CD39 only in patients with the permissive CD39 genotypes (G/G; A/G), but not in those with the A/A genotype. Two patients showing initial response to Moga experienced skin progression during treatment, which was associated with a significant increase of CD39 and simultaneous decrease of CD38 in residual circulating CD4+ T cells, although there was no evidence of blood relapse. These preliminary results suggest that partial or complete responses to Moga is paralleled by reduced CD39 and/or CD73 expression and increased CD38 expression. Instead, an opposite modulation of these markers is associated with disease progression hinting at the potential clinical utility of CD38, CD39 and CD73 as markers to monitor patients' response to Moga therapy. Citation Format: Yuliya Yakymiv, Sara Marchisio, Erika Ortolan, Verdiana Pullano, Chiara Leso, Rebecca Senetta, Lorenzo Marega, Gabriele Roccuzzo, Pietro Quaglino, Ada Funaro. CD39, CD73 and CD38 as potential biomarkers for monitoring the response to mogamulizumab in Sézary syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5171.

EDITORIAL article Front. Immunol., 27 June 2023Sec. Molecular Innate Immunity Volume 14 - 2023 | https://doi.org/10.3389/fimmu.2023.1239546

Letter to Blood| January 5, 2023 CD39/CD73 dysregulation and adenosine metabolism contribute to T-cell immunosuppression in patients with Sézary syndrome Yuliya Yakymiv, Yuliya Yakymiv ∗ 1Laboratory of Immunogenetics, Department of Medical Sciences, University of Turin, Turin, Italy https://orcid.org/0000-0002-9598-3462 Search for other works by this author on: This Site PubMed Google Scholar Sara Marchisio, Sara Marchisio ∗ 1Laboratory of Immunogenetics, Department of Medical Sciences, University of Turin, Turin, Italy https://orcid.org/0000-0001-7005-837X Search for other works by this author on: This Site PubMed Google Scholar Erika Ortolan, Erika Ortolan 1Laboratory of Immunogenetics, Department of Medical Sciences, University of Turin, Turin, Italy https://orcid.org/0000-0003-2287-9020 Search for other works by this author on: This Site PubMed Google Scholar Cristiano Bracci, Cristiano Bracci 1Laboratory of Immunogenetics, Department of Medical Sciences, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Rebecca Senetta, Rebecca Senetta 2Pathology Unit, Department of Oncology, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Maria Rebecca Rumore, Maria Rebecca Rumore 2Pathology Unit, Department of Oncology, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Cristian Tampieri, Cristian Tampieri 3Pathology Unit, Department of Medical Sciences, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Marianna Fia, Marianna Fia 4Dermatologic Clinic, Department of Medical Sciences, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Simone Ribero, Simone Ribero 4Dermatologic Clinic, Department of Medical Sciences, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Ada Funaro, Ada Funaro † 1Laboratory of Immunogenetics, Department of Medical Sciences, University of Turin, Turin, Italy https://orcid.org/0000-0001-6341-1817 Search for other works by this author on: This Site PubMed Google Scholar Pietro Quaglino Pietro Quaglino † 4Dermatologic Clinic, Department of Medical Sciences, University of Turin, Turin, Italy Search for other works by this author on: This Site PubMed Google Scholar Blood (2023) 141 (1): 111–116. https://doi.org/10.1182/blood.2022017259 Article history Submitted: May 31, 2022 Accepted: August 14, 2022 Connected Content This is a related article to: CD39-CD73-adenosine effects in Sézary syndrome Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Request Permissions Cite Icon Cite Search Site Citation Yuliya Yakymiv, Sara Marchisio, Erika Ortolan, Cristiano Bracci, Rebecca Senetta, Maria Rebecca Rumore, Cristian Tampieri, Marianna Fia, Simone Ribero, Ada Funaro, Pietro Quaglino; CD39/CD73 dysregulation and adenosine metabolism contribute to T-cell immunosuppression in patients with Sézary syndrome. Blood 2023; 141 (1): 111–116. doi: https://doi.org/10.1182/blood.2022017259 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBlood Search Subjects: Immunobiology and Immunotherapy, Lymphoid Neoplasia TO THE EDITOR: Sézary syndrome (SS) is an aggressive subtype of cutaneous T-cell lymphoma, clinically presenting with erythroderma, lymphadenopathy, and atypical T cells (Sézary cells) in the skin, lymph nodes, and peripheral blood.1,2 As disease progresses, patients with SS develop severe immunodeficiency orchestrated by tumor cells and the tumor microenvironment (TME). This immunodeficiency is worsened by therapy and is responsible for a high incidence of life-threatening infections.3 Overexpression of CD39 and/or CD73 in malignant circulating SS T cells has previously been reported.4,5 Here we follow up on our preliminary data by investigating the functional role of the CD39/CD73 ectoenzymes in generating immunosuppressive extracellular adenosine (ADO) in patients with SS.6,7 Our patient cohort consisted of 11 patients with SS (supplemental Table 1, available on the Blood website). At first encounter and at... References 1.Willemze R, Cerroni L, Kempf W, et al. The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas. Blood. 2019;133(16):1703-1714.Google ScholarCrossrefSearch ADS PubMed 2.Scarisbrick JJ, Hodak E, Bagot M, et al. Blood classification and blood response criteria in mycosis fungoides and Sézary syndrome using flow cytometry: recommendations from the EORTC cutaneous lymphoma task force. Eur J Cancer. 2018;93:47-56.Google ScholarCrossrefSearch ADS PubMed 3.Quaglino P, Fava P, Pileri A, et al. Phenotypical markers, molecular mutations, and immune microenvironment as targets for new treatments in patients with mycosis fungoides and/or Sézary syndrome. J Invest Dermatol. 2021;141(3):484-495.Google ScholarCrossrefSearch ADS 4.Sonigo G, Bozonnat A, Dumont M, et al. Involvement of the CD39/CD73/adenosine pathway on T cell proliferation and NK cell-mediated ADCC in Sézary syndrome. Blood. 2022;139(17):2712-2716.Google ScholarCrossrefSearch ADS PubMed 5.Bensussan A, Janela B, Thonnart N, et al. Identification of CD39 as a marker for the circulating malignant T-cell clone of Sézary syndrome patients. J Invest Dermatol. 2019;139(3):725-728.Google ScholarCrossrefSearch ADS 6.Quaglino P, Funaro A, Ortolan E, et al. Prec-O1-05 - Flow-cytometry and functional evaluation of the CD39/CD73 adenosinergic immunosuppressive axis in patients with Sézary syndrome. Eur J Cancer. 2021;156(suppl 1):S12-S13.Google Scholar 7.Allard B, Allard D, Buisseret L, Stagg J. The adenosine pathway in immuno-oncology. Nat Rev Clin Oncol. 2020;17(10):611-629.Google ScholarCrossrefSearch ADS PubMed 8.Bernengo MG, Novelli M, Quaglino P, et al. The relevance of the CD4+ CD26– subset in the identification of circulating Sézary cells. Br J Dermatol. 2001;144(1):125-135.Google ScholarCrossrefSearch ADS PubMed 9.Lewis DJ, Rook AH. Mogamulizumab in the treatment of advanced mycosis fungoides and Sézary syndrome: safety and efficacy. Expert Rev Anticancer Ther. 2020;20(6):447-452.Google ScholarCrossrefSearch ADS PubMed 10.Picozza M, Cristofoletti C, Bresin A, et al. Genetically driven CD39 expression affects Sézary cell viability, IL-2 production and detects two patient subsets with distinct prognosis. J Invest Dermatol. 2022;142(11):3009-3019.Google ScholarCrossrefSearch ADS 11.Rissiek A, Baumann I, Cuapio A, et al. The expression of CD39 on regulatory T cells is genetically driven and further upregulated at sites of inflammation. J Autoimmun. 2015;58:12-20.Google ScholarCrossrefSearch ADS 12.Schneider E, Winzer R, Rissiek A, et al. CD73-mediated adenosine production by CD8 T cell-derived extracellular vesicles constitutes an intrinsic mechanism of immune suppression. Nat Commun. 2021;12(1):5911.Google ScholarCrossrefSearch ADS PubMed 13.Quaglino P, Novelli M, Fava P, et al. CD38 expression by circulating and skin-infiltrating lymphocytes from Sézary syndrome patients: a flow cytometry and immunohistochemistry study. Dis Markers. 2022;2022:3424413.Google ScholarCrossrefSearch ADS PubMed 14.Fortunato O, Belisario DC, Compagno M, et al. CXCR4 inhibition counteracts immunosuppressive properties of metastatic NSCLC stem cells. Front Immunol. 2020;11:2168.Google ScholarCrossrefSearch ADS 15.de Andrade Mello P, Coutinho-Silva R, Savio LEB. Multifaceted effects of extracellular adenosine triphosphate and adenosine in the tumor-host interaction and therapeutic perspectives. Front Immunol. 2017;8:1526.Google ScholarCrossrefSearch ADS PubMed 16.Giuliani AL, Sarti AC, Di Virgilio F. Ectonucleotidases in acute and chronic inflammation. Front Pharmacol. 2020;11:619458.Google ScholarCrossrefSearch ADS PubMed 17.Yip L, Woehrle T, Corriden R, et al. Autocrine regulation of T-cell activation by ATP release and P2X7 receptors. FASEB J. 2009;23(6):1685-1693.Google ScholarCrossrefSearch ADS PubMed 18.Cristofoletti C, Bresin A, Picozza M, et al. Blood and skin-derived Sézary cells: differences in proliferation-index, activation of PI3K/AKT/mTORC1 pathway and its prognostic relevance. Leukemia. 2019;33(5):1231-1242.Google ScholarCrossrefSearch ADS PubMed 19.Antonioli L, Fornai M, Blandizzi C, Pacher P, Hasko G. Adenosine signaling and the immune system: when a lot could be too much. Immunol Lett. 2019;205:9-15.Google ScholarCrossrefSearch ADS PubMed 20.Festag J, Thelemann T, Schell M, et al. Preventing ATP degradation by ASO-mediated knockdown of CD39 and CD73 results in A2aR-independent rescue of T cell proliferation. Mol Ther Nucleic Acids. 2020;21:656-669.Google ScholarCrossrefSearch ADS PubMed 21.Schiedel AC, Lacher SK, Linnemann C, Knolle PA, Muller CE. Antiproliferative effects of selective adenosine receptor agonists and antagonists on human lymphocytes: evidence for receptor-independent mechanisms. Purinergic Signal. 2013;9(3):351-365.Google ScholarCrossrefSearch ADS PubMed 22.Gorrell MD, Gysbers V, McCaughan GW. CD26: a multifunctional integral membrane and secreted protein of activated lymphocytes. Scand J Immunol. 2001;54(3):249-264.Google ScholarCrossrefSearch ADS PubMed 23.Yegutkin GG. Adenosine metabolism in the vascular system. Biochem Pharmacol. 2021;187:114373.Google ScholarCrossrefSearch ADS PubMed 24.Najidh S, Tensen CP, van der Sluijs-Gelling AJ, et al. Improved Sézary cell detection and novel insights into immunophenotypic and molecular heterogeneity in Sézary syndrome. Blood. 2021;138(24):2539-2554.Google ScholarCrossrefSearch ADS PubMed © 2023 by The American Society of Hematology2023 © 2023 by The American Society of Hematology2023 You do not currently have access to this content. Sign in via your Institution

Background. Reports on the expression of CD38 in Sézary syndrome (SS), erythrodermic primary cutaneous T cell lymphoma with leukemic involvement, are limited. The aim of the present study is the analysis of the expression of CD38 by skin-infiltrating mononuclear cells and circulating T lymphocytes in a cohort of SS patients. Methods. SS patients diagnosed since 1985 in our clinic were retrospectively analyzed for CD38 expression in biopsy and blood samples by immunohistochemistry and flow cytometry, respectively. Results. SS patients show a predominant CD38-negative phenotype on both skin and blood. A subgroup of patients was found expressing CD38 (12 cases) in either the skin (>25% cell infiltrate) or blood (CD4+CD38+ >50%), among whom 4 in the blood, 7 in the skin, and 1 in both blood and skin. Conclusion. The implications of these observations may be twofold: the relevance in basic science is related to a potential role in immune defense regulation, whilst in perspective CD38 may become a target for antibody therapy, considering the availability of different anti-CD38 monoclonal antibodies.

Abstract The authors have requested that this preprint be removed from Research Square.

Sézary syndrome is a rare subtype of cutaneous T-cell lymphoma characterized by erythroderma, peripheral lymphadenopathies, and circulating atypical cerebriform T-cells. To date, no definite staging system has been developed for these patients. In this retrospective analysis of the archive of the Dermatological Clinic of the University of Turin, Italy, erythrodermic SS patients were classified according to clinical records and photographs into three main presentations: erythematous, infiltrated, or melanodermic. The pattern of erythroderma was found to be associated with disease outcome, as better survivals were recorded in patients with erythematous and infiltrative erythroderma. Patients in the melanodermic group, though less represented in our investigation, seemed to show a worse trend in survival. According to this preliminary evidence, a new prognostic classification, with a revised score specific for Sézary syndrome patients, can be proposed to usefully integrate the current staging system. The correlation displayed in our research will be hopefully confirmed by prospective studies with larger cohorts, with the aim of identifying significant prognostic features in this subset of cutaneous T-cell lymphoma patients.

CD157/BST-1 (a member of the ADP-ribosyl cyclase family) is expressed at variable levels in 97% of patients with acute myeloid leukemia (AML), and is currently under investigation as a target for antibody-based immunotherapy. We used peripheral blood and bone marrow samples from patients with AML to analyse the impact of CD157-directed antibodies in AML survival and in response to cytarabine (AraC) ex vivo. The study was extended to the U937, THP1 and OCI-AML3 AML cell lines of which we engineered CD157-low versions by shRNA knockdown. CD157-targeting antibodies enhanced survival, decreased apoptosis and reduced AraC toxicity in AML blasts and cell lines. CD157 signaling activated the PI3K/AKT/mTOR and MAPK/ERK pathways and increased expression of Mcl-1 and Bcl-XL anti-apoptotic proteins, while decreasing expression of Bax pro-apoptotic protein, thus preventing Caspase-3 activation. The primary CD157-mediated anti-apoptotic mechanism was Bak sequestration by Mcl-1. Indeed, the Mcl-1-specific inhibitor S63845 restored apoptosis by disrupting the interaction of Mcl-1 with Bim and Bak and significantly increased AraC toxicity in CD157-high but not in CD157-low AML cells. This study provides a new role for CD157 in AML cell survival, and indicates a potential role of CD157 as a predictive marker of response to therapies exploiting Mcl-1 pharmacological inhibition.

Sézary syndrome (SS) is a primary cutaneous T-cell lymphoma characterized by measurable levels of malignant lymphocytes in the blood, and progressive impairment of the immune response. Among the mechanisms of immune modulation, adenosine can impair anti-tumor immunity, through the attenuation of protective effector cells, including T and NK cells, and by enhancing the suppressive capacity of T regulatory cells. CD39 and CD73 nucleotide-metabolizing enzymes are involved in the adenosine-generating pathway: CD39 cleaves ATP and ADP down into AMP, which is converted into adenosine by CD73. The extracellular adenosine deaminase/CD26 complex catalyzes the deamination of adenosine to inosine, thus reducing the adenosine levels. The objective of this study were: to investigate the expression of the of CD39 and CD73 nucleotide-metabolizing ectoenzymes in peripheral blood from SS patients; to define the contribution of the CD39/CD73 adenosinergic immunosuppressive pathway to tumor escape from immune response and immune dysfunctions in patients with SS. CD39 and CD73 expression analyzed in whole blood with multiparametric flow-cytometry from SS patients (n=10) and healthy donors (HD, n=11) revealed altered expression of CD39 and CD73 in SS patients compared to HD. Two subgroups of patients can be identified based on the mutually exclusive overexpression of CD39 or CD73 in CD4+ T cells. Indeed, 7 out of 10 patients had high CD39, while 3 had high CD73. CD4+T cells with high CD39 have low CD73, vice versa those with high CD73 have low CD39. To define whether CD39 and CD73 were biologically active, we compared the ability of peripheral blood CD4+T cells from SS patients and HD to hydrolyze ATP and to convert AMP into adenosine, in vitro. Briefly, CD4+ Tcells from SS/HD were seeded in 48-well plates in HBSS, pretreated or not with specific inhibitors for 1h and then incubated with exogenous (e) eATP (patients with high CD39) or eAMP (patients with high CD73) at 37°C. After 1 h incubation, analyses of the supernatant were performed with an RP-HPLC. Results indicated that CD4+ T cells from SS patients with high levels of CD39 showed an increased ability to hydrolyze ATP with increased generation of AMP compared to normal control cells. In parallel, CD4+ T cells with high levels of CD73 showed increased conversion of AMP into ADO, respect to normal control cells. The aberrant expression of CD39 and CD73 along with loss of CD26 expression in circulating Sézary cells suggest that the sequential activity of CD39 and CD73 ectoenzymes scavenges ATP and generates immunosuppressive adenosine in the tumor microenvironment contributing to tumor immune escape. The results inferred from this study are the starting point for more comprehensive studies towards the development of new therapies targeting the CD39/CD73 adenosinergic axis in order to overcome tumor immunosuppression, allowing the induction of effective anti-tumor immune response. Sézary syndrome (SS) is a primary cutaneous T-cell lymphoma characterized by measurable levels of malignant lymphocytes in the blood, and progressive impairment of the immune response. Among the mechanisms of immune modulation, adenosine can impair anti-tumor immunity, through the attenuation of protective effector cells, including T and NK cells, and by enhancing the suppressive capacity of T regulatory cells. CD39 and CD73 nucleotide-metabolizing enzymes are involved in the adenosine-generating pathway: CD39 cleaves ATP and ADP down into AMP, which is converted into adenosine by CD73. The extracellular adenosine deaminase/CD26 complex catalyzes the deamination of adenosine to inosine, thus reducing the adenosine levels. The objective of this study were: to investigate the expression of the of CD39 and CD73 nucleotide-metabolizing ectoenzymes in peripheral blood from SS patients; to define the contribution of the CD39/CD73 adenosinergic immunosuppressive pathway to tumor escape from immune response and immune dysfunctions in patients with SS. CD39 and CD73 expression analyzed in whole blood with multiparametric flow-cytometry from SS patients (n=10) and healthy donors (HD, n=11) revealed altered expression of CD39 and CD73 in SS patients compared to HD. Two subgroups of patients can be identified based on the mutually exclusive overexpression of CD39 or CD73 in CD4+ T cells. Indeed, 7 out of 10 patients had high CD39, while 3 had high CD73. CD4+T cells with high CD39 have low CD73, vice versa those with high CD73 have low CD39. To define whether CD39 and CD73 were biologically active, we compared the ability of peripheral blood CD4+T cells from SS patients and HD to hydrolyze ATP and to convert AMP into adenosine, in vitro. Briefly, CD4+ Tcells from SS/HD were seeded in 48-well plates in HBSS, pretreated or not with specific inhibitors for 1h and then incubated with exogenous (e) eATP (patients with high CD39) or eAMP (patients with high CD73) at 37°C. After 1 h incubation, analyses of the supernatant were performed with an RP-HPLC. Results indicated that CD4+ T cells from SS patients with high levels of CD39 showed an increased ability to hydrolyze ATP with increased generation of AMP compared to normal control cells. In parallel, CD4+ T cells with high levels of CD73 showed increased conversion of AMP into ADO, respect to normal control cells. The aberrant expression of CD39 and CD73 along with loss of CD26 expression in circulating Sézary cells suggest that the sequential activity of CD39 and CD73 ectoenzymes scavenges ATP and generates immunosuppressive adenosine in the tumor microenvironment contributing to tumor immune escape. The results inferred from this study are the starting point for more comprehensive studies towards the development of new therapies targeting the CD39/CD73 adenosinergic axis in order to overcome tumor immunosuppression, allowing the induction of effective anti-tumor immune response.

Short term treatment with low doses of glucocorticoid analogues has been shown to ameliorate neurological symptoms in Ataxia–Telangiectasia (A–T), a rare autosomal recessive multisystem disease that mainly affects the cerebellum, immune system, and lungs. Molecular mechanisms underlying this clinical observation are unclear. We aimed at evaluating the effect of dexamethasone on the induction of alternative ATM transcripts ( ATMdexa1 ). We showed that dexamethasone cannot induce an alternative ATM transcript in control and A–T lymphoblasts and primary fibroblasts, or in an ATM - knockout HeLa cell line. We also demonstrated that some of the reported readouts associated with ATMdexa1 are due to cellular artifacts and the direct induction of γH2AX by dexamethasone via DNA-PK . Finally, we suggest caution in interpreting dexamethasone effects in vitro for the results to be translated into a rational use of the drug in A–T patients.

•CD157 is a dual-function receptor and β-NAD+-metabolizing ectoenzyme.•CD157 regulates leukocyte trafficking.•CD157 plays a role in inflammation and in selected tumors.•CD157 is a promising target for antibody-mediated immunotherapy in acute myeloid leukemia.