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Dive into the research topics where Panagiotis T. Diamantopoulos is active.

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Featured researches published by Panagiotis T. Diamantopoulos.


Virology Journal | 2012

Antiretroviral activity of 5-azacytidine during treatment of a HTLV-1 positive myelodysplastic syndrome with autoimmune manifestations.

Panagiotis T. Diamantopoulos; Maria Michael; Olga Benopoulou; Efthymia Bazanis; George Tzeletas; John Meletis; George Vayopoulos; Nora-Athina Viniou

Myelodysplastic syndromes (MDS) are often accompanied by autoimmune phenomena. The underlying mechanisms for these associations remain uncertain, although T cell activation seems to be important. Human T-lymphotropic virus (HTLV-1) has been detected in patients with myelodysplastic syndromes, mostly in regions of the world which are endemic for the virus, and where association of HTLV-1 with rheumatological manifestation is not rare. We present here the case of a 58 year old man who presented with cytopenias, leukocytoclastic vasculitis of the skin and glomerulopathy, and was diagnosed as MDS (refractory anemia with excess blasts - RAEB 1). The patient also tested positive for HTLV-1 by PCR. After 8 monthly cycles of 5-azacytidine he achieved a complete hematologic remission. Following treatment, a second PCR for HTLV-1 was carried out and found to be negative. This is the first report in the literature of a HTLV-1-positive MDS with severe autoimmune manifestations, which was treated with the hypomethylating factor 5-azacitidine, achieving cytogenetic remission with concomitant resolution of the autoimmune manifestations, as well as HTLV-1-PCR negativity. HTLV-1-PCR negativity may be due to either immune mediated clearance of the virus, or a potential antiretroviral effect of 5-azacytidine. 5-azacytidine is known for its antiretroviral effects, although there is no proof of its activity against HTLV-1 infection in vivo.


Leukemia & Lymphoma | 2013

Correlation of Fc-γ RIIA polymorphisms with latent Epstein–Barr virus infection and latent membrane protein 1 expression in patients with low grade B-cell lymphomas

Panagiotis T. Diamantopoulos; Vassiliki Kalotychou; Katerina Polonyfi; Maria Sofotasiou; Amalia Anastasopoulou; Athanassios Galanopoulos; Nikolaos Spanakis; Theodoros P. Vassilakopoulos; Maria K. Angelopoulou; Maria Siakantaris; Eleni Variami; Christos Poziopoulos; Evangelos Terpos; Panagoula Kollia; Nora-Athina Viniou

Abstract Fc-γ RIIA (CD32), a member of the family of Fc-γ receptors, participates in the phagocytosis of bound to antibody antigens. The effectiveness of this function varies for its several haplotypes, and it participates in the pathogenesis of viral infections, according to recent studies. The genetic locus of Fc-γ RIIA consists of two allelic genes: 131-Arg (R131) and 131-His (H131). Our aim was to correlate Fc-γ RIIA polymorphisms, by studying the prevalence of each allele using PCR-RFLPs (polymerase chain reaction-restriction fragment length polymorphisms), with latent Epstein–Barr virus (EBV) infection and the expression of latent membrane protein 1 (LMP1) in 40 patients with leukemic low grade B-cell lymphomas. R131 was found in 84.2% of EBV-positive patients, but only in 28.5% of EBV-negative patients (p = 0.001). A similar correlation was found for R131 and LMP1 expression (84.6% vs. 28.5%) (p = 0.002). Our results support the hypothesis that Fc-γ RIIA polymorphisms are a genetic risk factor for latent EBV infection and the expression of its oncogenic latency proteins.


BioMed Research International | 2014

PARP1-driven apoptosis in chronic lymphocytic leukemia.

Panagiotis T. Diamantopoulos; Maria Sofotasiou; Vasiliki Papadopoulou; Katerina Polonyfi; Theodoros Iliakis; Nora-Athina Viniou

Chronic lymphocytic leukemia (CLL) is considered a malignancy resulting from defects in apoptosis. For this reason, targeting apoptotic pathways in CLL may be valuable for its management. Poly [ADP-ribose] polymerase 1 (PARP1) is the main member of a family of nuclear enzymes that act as DNA damage sensors. Through binding on DNA damaged structures, PARP1 recruits repair enzymes and serves as a survival factor, but if the damage is severe enough, its action may lead the cell to apoptosis through caspase activation, or necrosis. We measured the PARP1 mRNA and protein pretreatment levels in 26 patients with CLL and the corresponding posttreatment levels in 15 patients after 3 cycles of immunochemotherapy, as well as in 15 healthy blood donors. No difference was found between the pre- and posttreatment levels of PARP1, but we found a statistically significant relative increase of the 89 kDa fragment of PARP1 that is cleaved by caspases in the posttreatment samples, indicating PARP1-related apoptosis in CLL patients after treatment. Our findings constitute an important step in the field, especially in the era of PARP1 inhibitors, and may serve as a base for future clinical trials with these agents in CLL.


Melanoma Research | 2017

Late-onset nivolumab-mediated pneumonitis in a patient with melanoma and multiple immune-related adverse events

Panagiotis T. Diamantopoulos; Maria Gaggadi; Eva Kassi; Olga Benopoulou; Amalia Anastasopoulou; Helen Gogas

Immune-related adverse effects (AEs) of PD-1 inhibitors can affect almost every organ, but the skin, intestine, lung, eye, and liver are the most commonly affected organs. Here, we present the case of a 62-year-old female patient with stage IIIc melanoma treated with nivolumab in an adjuvant setting who sequentially developed hyperthyroidism, hypothyroidism, acute hepatitis, and pneumonitis. Six months before the emergence of pneumonitis, the patient had discontinued treatment with nivolumab because of acute hepatitis. Information on pneumonitis after nivolumab discontinuation in the literature is scarce, whereas most of the cases emerge during the first 2.5 months of treatment. Patients with multiple immune-related AEs comprise a group of special interest as the identification of factors affecting the susceptibility of patients to immune-related AEs of PD-1 inhibitors may lead to a more rational use of these drugs. Human leukocyte antigen haplotype and Fcγ receptor polymorphisms are possible targets of the relevant research.


Journal of Immunotherapy | 2017

Inflammatory Myopathy and Axonal Neuropathy in a Patient With Melanoma Following Pembrolizumab Treatment

Panagiotis T. Diamantopoulos; Katerina Tsatsou; Olga Benopoulou; Amalia Anastasopoulou; Helen Gogas

Immune-mediated adverse effects of immune checkpoint inhibitors are rather common, but neuromyopathic immune-related adverse events are very rare. In this report, we present a unique case of a patient with a complex neuromyopathic syndrome with axonal neuropathy and inflammatory myopathy after a single dose of pembrolizumab. An 82-year-old patient with a previously untreated stage IIIc melanoma developed ptosis in the left eye, generalized weakness, and neck and shoulder pain 15 days after pembrolizumab administration. He had left-sided ptosis and miosis, with a normal pupillary light reflex, horizontal diplopia, and voice hoarseness, along with weakness of the neck muscles and a hypokinetic right vocal cord at laryngoscopy. The laboratory evaluation was remarkable for the marked increase in the serum lactate dehydrogenase and creatine phosphokinase levels. Further evaluation revealed findings compatible with axonal neuropathy and inflammatory myopathy. The patient was treated with corticosteroids, immunoglobulin, and plasmapheresis, with a minor response; the patient eventually died. This case represents a newly described syndrome probably associated with pembrolizumab administration.


Leukemia & Lymphoma | 2014

Evidence for regulation of oxidative stress by latent membrane protein 1 oncoprotein in patients with low-grade leukemic B cell lymphoma with latent Epstein - Barr virus infection

Vasiliki Papadopoulou; Panagiotis T. Diamantopoulos; Elina Kontandreopoulou; Katerina Polonyfi; Eleni Variami; Panagiotis Kouzis; Athanasios Galanopoulos; Nikolaos Spanakis; Konstantinos Zervakis; Theodoros Iliakis; Despoina Perrea; Panagoula Kollia; Theodoros P. Vassilakopoulos; Gerassimos A. Pangalis; Christine Kyrtsonis; George Vaiopoulos; Nora-Athina Viniou

Abstract The role of latent Epstein–Barr virus (EBV) infection in the pathogenesis of low-grade B cell non-Hodgkin lymphoma (B-NHL) has not been studied. We therefore investigated the incidence of latent EBV infection in a group of patients with leukemic low-grade B-NHL, as well as the incidence of viral latent membrane protein 1 (LMP1) oncoprotein expression in the same patient group. Furthermore, in an attempt to elucidate the role of this viral oncoprotein in non-EBV-related lymphomas, we correlated the expression of LMP1 with the level of oxidative stress, a parameter related to apoptosis. In the present study we detected lower levels of oxidative stress in the sera of LMP1-positive patients. This possibly implies an anti-apoptotic role of this viral oncoprotein in low-grade B cell lymphomas. However, LMP1 expression status did not affect expression of the major anti-apoptotic gene BCL-2.


Case Reports in Medicine | 2014

An Adult Patient with Systemic Mastocytosis and B-Acute Lymphoblastic Leukemia

Theodoros Iliakis; Niki Rougkala; Panagiotis T. Diamantopoulos; Vasiliki Papadopoulou; Fani Kalala; Konstantinos Zervakis; Nefeli Giannakopoulou; Polixeni Chatzinikolaou; Georgia Levidou; Eleftheria Lakiotaki; Penelope Korkolopoulou; Efstratios Patsouris; Eleni Variami; Nora-Athina Viniou

Mastocytosis is a myeloproliferative neoplasm characterized by clonal expansion of abnormal mast cells, ranging from the cutaneous forms of the disease to mast cell leukemia. In a significant proportion of patients, systemic mastocytosis (SM) coexists with another hematologic malignancy, termed systemic mastocytosis with an associated hematologic nonmast cell lineage disorder (SM-AHNMD). Despite the pronounced predominance of concomitant myeloid neoplasms, the much more unusual coexistence of lymphoproliferative diseases has also been reported. Imatinib mesylate (IM) has a role in the treatment of SM in the absence of the KITD816V mutation. In the setting of SM-AHNMD, eradicating the nonmast cell malignant clone greatly affects prognosis. We report a case of an adult patient with SM associated with B-lineage acute lymphoblastic leukemia (B-ALL). Three cases of concurrent adult ALL and mastocytosis have been reported in the literature, one concerning SM and two concerning cutaneous mastocytosis (CM), as well as six cases of concomitant CM and ALL in children.


Leukemia & Lymphoma | 2012

Leukemic transformation in patients with myelodysplastic syndromes after treatment with granulocyte colony-stimulating factor.

Panagiotis T. Diamantopoulos; Titika Chatzileonida; Athanasios Galanopoulos; Xanthi Yiakoumis; Angeliki-Maria Saridaki; Antonios Angelidis; Evangelos Papakostas; Efthymia Bazanis; Sotirios Sachanas; Maria Michael; Gerassimos A. Pangalis; Nikolaos Anagnostopoulos; John Meletis; Nora-Athina Viniou

Myelodysplastic syndromes (MDS) constitute bone marrow malignancies occurring mainly in older individuals and associated with acute myeloid leukemia (AML) transformation in 30 – 40% of cases [1]. In order to assess long-term survival and the AML transformation rate, in 1997 the International MDS Risk Analysis Workshop developed the International Prognostic Scoring System (IPSS), which divides patients with MDS into four risk groups: low, intermediate-1, intermediate-2 and high. Determining the prognosis of MDS is crucial in the eff ort toward defi ning the best treatment for each group [2]. When patients with MDS develop cytopenias and/or blood product transfusion dependency, treatment with growth factors may be initiated according to most treatment guidelines. Th ese include epoetin or darbepoetin and colony-stimulating factors, either alone or in combination, acting in synergy. A number of trials have been published, with erythroid response rates of around 40% in patients with lower-risk disease using International Working Group (IWG) criteria for response [3 – 5]. Some studies have shown a clear synergistic eff ect between the two drugs [6 – 8]. Th e negative impact of treatment with growth factors is widely discussed in the literature relating to solid tumors. Th ere are studies indicating that granulocyte colony-stimulating factor (G-CSF) may increase the risk of AML evolution in aplastic anemia [9] and severe congenital neutropenia [10,11], while other studies suggest a favorable response of patients with MDS to treatment including G-CSF [12]. Th e aim of this retrospective study was to assess the eff ect of treatment with G-CSF on leukemic transformation in 92 consecutive patients with MDS treated in two hematology units in Athens, Greece, between 1996 and 2005. Th e medical records of these patients were retrospectively reviewed. Bone marrow biopsies were reevaluated and diagnosis confi rmed. We used the French – American – British (FAB) classifi cation for MDS instead of the more recent World Health Organization (WHO) classifi cation for practical reasons and due to the presence of patients with chronic myelomonocytic leukemia (CMML). We excluded patients with refractory anemia with excess blasts in transformation (RAEB-T) ( n 16), as well as patients who were considered non-evaluable ( n 5) and


Hamostaseologie | 2017

Advances in anticoagulation management of patients undergoing cardioversion of nonvalvular atrial fibrillation

Georgios Benetos; Maria Bonou; Konstantinos Toutouzas; Panagiotis T. Diamantopoulos; Nora Viniou; John Barbetseas

Atrial fibrillation (AF) is a major cause of stroke. The restoration of sinus rhythm through cardioversion, either chemical or electrical is a common practice. Interestingly, there is an incremental increase from the baseline risk for embolisation in the immediate post-cardioversion period, with most events occurring within 10 days from cardioversion. Especially patients with recent onset AF show the lowest rates of antithrombotic therapy, while having a high stroke risk. Despite the increased risk for embolisation, anticoagulation in patients undergoing cardioversion of atrial fibrillation is often inadequate. Moreover, since the implementation of non-vitamin K antagonists oral anticoagulants (DOACs) there are several therapeutic approaches for pericardioversion anticoagulant therapy and not all suits to all patients. In addition, the extensive use of transesophageal echocardiography provides an alternative strategy, especially useful for patients of high haemorrhagic risk. In this review article, we aim to provide an update on the anticoagulation strategies for patients undergoing cardioversion of non-valvular atrial fibrillation in the advent of the use of DOACs.


Cancer Medicine | 2016

Prognostic significance of signal transducer and activator of transcription 5 and 5b expression in Epstein–Barr virus-positive patients with chronic lymphocytic leukemia

Panagiotis T. Diamantopoulos; Maria Sofotasiou; Zafiroula Georgoussi; Nefeli Giannakopoulou; Vasiliki Papadopoulou; Athanasios Galanopoulos; Elina Kontandreopoulou; Panagiotis Zervakis; Paschalina Pallaki; Fani Kalala; Marie-Christine Kyrtsonis; Aglaia Dimitrakopoulou; Theodoros P. Vassilakopoulos; Maria K. Angelopoulou; Nikolaos Spanakis; Nora-Athina Viniou

Signal transducer and activator of transcription (STAT) proteins have been intensively studied in hematologic malignancies, and the efficacy of agents against STATs in lymphomas is already under research. We investigated the expression of total STAT5 and STAT5b in peripheral blood samples of patients with chronic lymphocytic leukemia (CLL) in correlation with the presence of Epstein–Barr Virus (EBV) and its major oncoprotein (latent membrane protein 1, LMP1). The EBV load was measured in the peripheral blood by real‐time PCR for the BXLF1 gene and the levels of LMP1 by PCR and ELISA. Western blotting was performed for total STAT5 and STAT5b in protein extracts. STAT5b was only expressed in patients (not in healthy subjects) and STAT5 but particularly STAT5b expression was correlated with the presence of the virus (77.3% vs. 51.2%, P = 0.006 for STAT5b) and to the expression of LMP1 (58.3% vs. 21.6%, P = 0.011 for STAT5b). Moreover, the expression of STAT5b and the presence of EBV and LMP1 were strongly negatively correlated with the overall survival of the patients (log‐rank test P = 0.011, 0.015, 0.006, respectively). Double positive (for EBV and STAT5b) patients had the lowest overall survival (log‐rank test P = 0.013). This is the first report of a survival disadvantage of EBV+ patients with CLL, and the first time that STAT5b expression is correlated with survival. The correlation of STAT5 expression with the presence of the virus, along with our survival correlations defines a subgroup of patients with CLL that may benefit from anti‐STAT agents.

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Nora-Athina Viniou

National and Kapodistrian University of Athens

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Eleni Variami

National and Kapodistrian University of Athens

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Konstantinos Zervakis

National and Kapodistrian University of Athens

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Theodoros P. Vassilakopoulos

National and Kapodistrian University of Athens

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Nefeli Giannakopoulou

National and Kapodistrian University of Athens

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Athanasios Galanopoulos

National and Kapodistrian University of Athens

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Maria K. Angelopoulou

National and Kapodistrian University of Athens

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Theodoros Iliakis

National and Kapodistrian University of Athens

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Fani Kalala

National and Kapodistrian University of Athens

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Vasiliki Papadopoulou

National and Kapodistrian University of Athens

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