Dimitrios Tzanetakos

Dr. Dimitrios Tzanetakos

Second Department of Neurology, School of Medicine, 'Attikon' University Hospital, National and Kapodistrian University of Athens, Athens, Attikí, Greece
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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 March 2022 in Neurology Neuroimmunology & Neuroinflammation
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KKKaterina Karagiorgou
Katerina Karagiorgou
MDMaria Dandoulaki
Maria Dandoulaki
Renato MantegazzaRenato Mantegazza
Renato Mantegazza
FAFrancesca Andreetta
Francesca Andreetta
RFRaffaello Furlan
Raffaello Furlan
STSocrates Tzartos
Socrates Tzartos
Background and Objectives Autoantibodies against α3-subunit–containing nicotinic acetylcholine receptors (α3-nAChRs), usually measured by radioimmunoprecipitation assay (RIPA), are detected in patients with autoimmune autonomic ganglionopathy (AAG). However, low α3-nAChR antibody levels are frequently detected in other neurologic diseases with questionable significance. Our objective was to develop a method for the selective detection of the potentially pathogenic α3-nAChR antibodies, seemingly present only in patients with AAG. Methods The study involved sera from 55 patients from Greece, suspected for autonomic failure, and 13 patients from Italy diagnosed with autonomic failure, positive for α3-nAChR antibodies by RIPA. In addition, sera from 52 patients with Ca2+ channel or Hu antibodies and from 2,628 controls with various neuroimmune diseases were included. A sensitive live cell-based assay (CBA) with α3-nAChR–transfected cells was developed to detect antibodies against the cell-exposed α3-nAChR domain. Results Twenty-five patients were found α3-nAChR antibody positive by RIPA. Fifteen of 25 patients were also CBA positive. Of interest, all 15 CBA-positive patients had AAG, whereas all 10 CBA-negative patients had other neurologic diseases. RIPA antibody levels of the CBA-negative sera were low, although our CBA could detect dilutions of AAG sera corresponding to equally low RIPA antibody levels. No serum bound to control-transfected cells, and none of the 2,628 controls was α3-CBA positive. Discussion This study showed that in contrast to the established RIPA for α3-nAChR antibodies, which at low levels is of moderate disease specificity, our CBA seems AAG specific, while at least equally sensitive with the RIPA. This study provides Class II evidence that α3-nAChR CBA is a specific assay for AAG. Classification of Evidence This study provides Class II evidence that an α3-nAChR cell-based assay is a more specific assay for AAG than the standard RIPA.

1 January 2021 in Therapeutic Advances in Neurological Disorders
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AVAigli G Vakrakou
Aigli G Vakrakou
DTDimitrios Tzanetakos
Dimitrios Tzanetakos
MEMaria-Eleptheria Evangelopoulos
Maria-Eleptheria Evangelopoulos
TATheodore Argyrakos
Theodore Argyrakos
JTJohn S. Tzartos
John S. Tzartos
CKConstantinos Kilidireas
Constantinos Kilidireas
Our goal was to expand the spectrum of clinico-radiologic characteristics and the possible therapeutic choices in patients with tumefactive demyelinating lesions (TDLs). A retrospective analysis of 50 patients with at least one TDL was performed at an academic neurology center (2008–2020). Our cohort comprised mostly women (33/50) with a mean age of 38 years at TDL onset. The mean follow-up time was 76 months. The mean Expanded Disability Status Scale score at TDL onset and at the latest neurological evaluation was 3.7 and 2.3, respectively. We subcategorized the patients into seven groups based mainly on the clinical/radiological findings and disease course. Group A included patients presenting with a Marburg-like TDL (n = 4). Groups B and C comprised patients presenting with monophasic (n = 7) and recurrent TDLs (n = 12), respectively. Multiple sclerosis (MS) patients who subsequently developed TDL (n = 16) during the disease course were categorized as Group D. Group E comprised patients who initially presented with TDL and subsequently developed a classical relapsing–remitting MS without further evidence of TDL (n = 5). Groups F (n = 2) and G (n = 4) involved MS patients who developed TDL during drug initiation (natalizumab, fingolimod) and cessation (interferon, fingolimod), respectively. Regarding long-term treatments applied after corticosteroid administration in the acute phase, B-cell-directed therapies were shown to be highly effective especially in cases with recurrent TDLs. Cyclophosphamide was spared for more aggressive disease indicated by a poor response to corticosteroids and plasma exchange failure. Tumefactive central nervous system demyelination is an heterogenous disease; its stratification into distinct groups according to different phenotypes can establish more efficient treatment strategies, thus improving clinical outcomes in the future.

2 November 2020 in BMC Neurology
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DTDimitrios Tzanetakos
Dimitrios Tzanetakos
AVA. G. Vakrakou
A. G. Vakrakou
JTJ. S. Tzartos
J. S. Tzartos
GVGeorgios Velonakis
Georgios Velonakis
MEM. E. Evangelopoulos
M. E. Evangelopoulos
CKC. Kilidireas
C. Kilidireas
Background Baló’s Concentric Sclerosis (BCS) is a rare heterogeneous demyelinating disease with a variety of phenotypes on Magnetic Resonance Imaging (MRI). Existing literature lacks data especially on the therapeutic approach of the disease which we intended to elucidate by means of suggesting a new possible BCS classification and introducing different therapeutic concepts based on each BCS-subgroup characteristics. Methods We present a retrospective study of eight treated patients with BCS-type lesions, emphasizing on MRI characteristics and differences on therapeutic maneuvers. Results Data analysis showed: at disease onset the BCS-type lesion was tumefactive (size ≥2 cm) in 6 patients, with a mean size of 2.7 cm (± 0.80 SD); a coexistence of MS-like plaques on brain MRI was identified in 7 patients of our cohort. The mean age was 26.3 years (±7.3 SD) at disease onset and the mean follow-up period was 56.8 months (range 9–132 months). According to radiological characteristics and response to therapies, we further categorized them into 3 subgroups: a) Group-1; BCS with or without coexisting nonspecific white matter lesions; poor response to intravenous methylprednisolone (IVMP); treated with high doses of immunosuppressive agents (4 patients), b) Group-2; BCS with typical MS lesions; good response to IVMP; treated with MS-disease modifying therapies (2 patients), c) Group-3; BCS with typical MS lesions; poor response to IVMP; treated with rituximab (2 patients). Conclusions Our study introduces a new insight regarding the categorization of BCS into three subgroups depending on radiological features at onset and during the course of the disease, in combination with the response to different immunotherapies. Immunosuppressive agents such as cyclophosphamide are usually effective in BCS. However, therapeutic alternatives like anti-CD20 monoclonal antibodies or more classical disease-modifying MS therapies can be considered when BCS has also mixed lesions similar to MS. Future studies with a larger sample size are necessary to further establish these findings, thus leading to better treatment algorithms and improved clinical outcomes.

2 January 2020 in Rheumatology International
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AVAigli G Vakrakou
Aigli G Vakrakou
Maria Eleftheria EvangelopoulosMaria Eleftheria Evangelopoulos
Maria Eleftheria Evangelopoulos
GBGeorgios Boutzios
Georgios Boutzios
DTDimitrios Tzanetakos
Dimitrios Tzanetakos
STSocrates Tzartos
Socrates Tzartos
CKConstantinos Kilidireas
Constantinos Kilidireas

14 November 2022 in Journal of Clinical Medicine
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ATAikaterini Theodorou
Aikaterini Theodorou
LPLina Palaiodimou
Lina Palaiodimou
ASApostolos Safouris
Apostolos Safouris
OKOdysseas Kargiotis
Odysseas Kargiotis
KPKlearchos Psychogios
Klearchos Psychogios
Georgios TsivgoulisGeorgios Tsivgoulis
Georgios Tsivgoulis
Background: Limited data exist regarding the prevalence of clinical, neuroimaging, and genetic markers among patients diagnosed with Cerebral Amyloid Angiopathy–related inflammation (CAA-ri). We sought to determine these characteristics in patients diagnosed in our center and to summarize available literature published either as single-case reports or small case series (<5 patients). Methods: We reported our single-center experience of patients diagnosed with CAA-ri according to international criteria during a seven-year period (2015–2022), and we abstracted data from 90 previously published cases. Results: Seven patients (43% women, mean age 70 ± 13 years) were diagnosed with CAA-ri in our center. The most common symptom at presentation was focal neurological dysfunction (71%), and the most prevalent radiological finding was the presence of T2/FLAIR white matter hyperintensities (100%). All patients were treated with corticosteroids and had a favorable functional outcome. Among 90 previously published CAA-ri cases (51% women, mean age 70 ± 9 years), focal neurological dysfunction was the most common symptom (76%), followed by a cognitive decline (46%) and headache (34%). The most prevalent neuroimaging findings were cerebral microbleeds (85%), asymmetric T2/FLAIR white matter hyperintensities (81%), and gadolinium-enhancing T1-lesions (37%). Genetic testing for the Apolipoprotein-E gene was available in 27 cases; 59% carried the APOE ε4/ε4 genotype. The majority of the published CAA-ri cases (78%) received corticosteroid monotherapy, while 17 patients (19%) were treated with additional immunosuppressive treatment. Favorable functional outcome following treatment was documented in 70% of patients. Conclusion: Improving the vigilance of clinicians regarding the early recognition and accurate diagnosis of CAA-ri is crucial for swift therapy initiation, which may result in improved functional outcomes.

29 October 2018 in BMC Neurology
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AVAigli G Vakrakou
Aigli G Vakrakou
DTDimitrios Tzanetakos
Dimitrios Tzanetakos
SVSERENA VALSAMI
SERENA VALSAMI
EGE. Grigoriou
E. Grigoriou
KPKatherina Psarra
Katherina Psarra
CKC. Kilidireas
C. Kilidireas
Alemtuzumab has been demonstrated to reduce the risks of relapse and accumulation of sustained disability in Multiple Sclerosis (MS) patients compared to β-interferon. It acts against CD52, leading primarily to lymphopenia. Recent data have shown that mild neutropenia is observed in 16% of treated MS-patients whereas severe neutropenia occurred in 0.6%. Herein, we present the case of a 34-year-old woman with relapsing-remitting MS, with a history of treatment with glatiramer acetate and natalizumab, who subsequently received Alemtuzumab (12 mg / 24 h × 5 days). 70-days after the last Alemtuzumab administration, the patient displayed neutropenia (500 neutrophils/μL) with virtual absence of B-cells (0.6% of total lymphocytes), low values of CD4-T-cells (6.6%) and predominance of CD8-T-cells (48%) and NK-cells (47%); while large granular lymphocytes (LGL) predominated in the blood-smear examination. Due to prolonged neutropenia (5-days) the patient was placed on low-dose corticosteroids leading to sustained remission. This is the first case of a patient with relapsing-remitting MS with neutropenia two months post-Alemtuzumab, with simultaneous presence of LGL cells in the blood and a robust therapeutic response to prednisolone. We recommend testing with a complete blood count every 15 days in the first 3 months after the 1st Alemtuzumab administration and searching for large granular lymphocytes cell expansion on microscopic examination of the peripheral blood if neutropenia develops.