Publications by Year: 2019

2019
Ramos EM, Koros C, Dokuru DR, Van, Berlo V, Kroupis C, Wojta K, Wang Q, Andronas N, Matsi S, Beratis IN, et al. Frontotemporal dementia spectrum: first genetic screen in a Greek cohort. Neurobiol.Aging [Internet]. 2019;75:224 - 224. WebsiteAbstract
Frontotemporal dementia (FTD) is a heterogeneous group of neurodegenerative syndromes associated with several causative and susceptibility genes. Herein, we aimed to determine the incidence of the most common causative dementia genes in a cohort of 118 unrelated Greek FTD spectrum patients. We also screened for novel possible disease-associated variants in additional 21 genes associated with FTD or amyotrophic lateral sclerosis. Pathogenic or likely pathogenic variants were identified in 16 cases (13.6%). These included repeat expansions in C9orf72 and loss-of-function GRN variants, and likely pathogenic variants in TARDBP, MAPT, and PSEN1. We also identified 14 variants of unknown significance in other rarer FTD or amyotrophic lateral sclerosis genes that require further segregation and functional analysis. Our genetic screen revealed a high genetic burden in familial Greek FTD cases (30.4%), whereas only two of the sporadic cases (3.5%) carried a likely pathogenic variant. A substantial number of familial cases still remain without an obvious causal variant, suggesting the existence of other FTD genetic causes besides those currently screened in clinical routine
Thelen M, Vanstapel F, Brguljan PM, Gouget B, Boursier G, Barrett E, Kroupis C, Lohmander M, Sprongl L, Vodnik T, et al. Documenting metrological traceability as intended by ISO 15189:2012: A consensus statement about the practice of the implementation and auditing of this norm element. Clin.Chem.Lab Med. [Internet]. 2019;57(4):459 - 464. WebsiteAbstract
ISO15189:2012 requires medical laboratories to document metrological traceability of their results. While the ISO17511:2003 standard on metrological traceability in laboratory medicine requires the use of the highest available level in the traceability chain, it recognizes that for many measurands there is no reference above the manufacturer's selected measurement procedure and the manufacturer's working calibrator. Some immunoassays, although they intend to measure the same quantity and may even refer to the same reference material, unfortunately produce different results because of differences in analytical selectivity as manufacturers select different epitopes and antibodies for the same analyte. In other cases, the cause is the use of reference materials, which are not commutable. The uncertainty associated with the result is another important aspect in metrological traceability implementation. As the measurement uncertainty on the clinical samples is influenced by the uncertainty of all steps higher in the traceability chain, laboratories should be provided with adequate and appropriate information on the uncertainty of the value assignment to the commercial calibrators that they use. Although the between-lot variation in value assignment will manifest itself as part of the long-term imprecision as estimated by the end-user, information on worst-case to be expected lot-lot variation has to be communicated to the end-user by the IVD provider. When laboratories use ancillary equipment that potentially could have a critical contribution to the reported results, such equipment needs verification of its proper calibration and criticality to the result uncertainty could be assessed by an approach based on risk analysis, which is a key element of ISO15189:2012 anyway. This paper discusses how the requirement for metrological traceability as stated in ISO15189 should be met by the medical laboratory and how this should be assessed by accreditation bodies
Moschos MM, Diamantopoulou A, Gouliopoulos N, Droutsas K, Bagli E, Chatzistefanou K, Kitsos G, Kroupis C. TCF4 and COL8A2 Gene Polymorphism Screening in a Greek Population of Late-onset Fuchs Endothelial Corneal Dystrophy. In Vivo [Internet]. 2019;33(3):963 - 971. WebsiteAbstract
BACKGROUND/AIM: Fuchs' endothelial corneal dystrophy (FECD) is a hereditary, progressive, bilateral, and irreversible disorder of the corneal endothelium. The purpose of this study was to develop a novel, accurate and high-throughput real-time polymerase chain reaction (PCR) method and melting-curve analysis in order to genotype the rs613872 polymorphism in the transcription factor 4 (TCF4) gene and to implement it on a well-ascertained sample of 22 Greek FECD patients and 58 healthy individuals, age- and sex-matched. PATIENTS AND METHODS: DNA was extracted from blood samples, which were screened with the DNA sequencing method in order to detect the g.31753T>G/p.L450W (rs8035192) and g.31767C>A/p.Q455K (rs8035191) mutations in a COL8A2 genomic region. RESULTS: TCF4 risk G allele frequency increased to 48% in FECD patients compared to 17% in healthy-subjects [OR=4.82 (95% CI=1.98-11.73)]. No p.L450W and p.Q455K COL8A2 gene mutations were detected. CONCLUSION: We confirmed that rs613872 in the TCF4 gene is strongly and statistically associated with late-onset FECD in a Greek population
Antalis E, Spathis A, Kottaridi C, Kossyvakis A, Pastellas K, Tsakalos K, Mentis A, Kroupis C, Tsiodras S. Th17 serum cytokines in relation to laboratory-confirmed respiratory viral infection: A pilot study. J.Med.Virol. [Internet]. 2019;91(6):963 - 971. WebsiteAbstract
BACKGROUND: Th17 cytokines are associated with modulation of inflammation and may be beneficial in clearing influenza infection in experimental models. The Th17 cytokine profile was evaluated in a pilot study of respiratory virus infections. METHODS: Consecutive patients with symptoms of respiratory tract infection visiting the emergency department of a tertiary care hospital during the winter influenza season of 2014 to 2015 were evaluated. CLART PneumoVir kit, (GENOMICA, Madrid, Spain) was used for viral detection of all known respiratory viruses. Th17 cytokine profile was evaluated with the MILLIPLEX MAP Human TH17 Magnetic Bead Panel (Millipore Corp., Billerica, MA). Correlation of the TH17 profile with viral detection was performed with univariate and multivariate analysis. RESULTS: Seventy-six patients were evaluated (median age 56 years, 51.3% female); a respiratory virus was identified in 60 (78.9%) patients; 45% had confirmed influenza. Influenza A (H3N2) correlated with higher levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 1beta (IL-1beta), IL-17A, IL-17E, IL-17F, IL-21, IL-22, and IL-23 (P < 0.05 by analysis of variance [ANOVA]) compared with respiratory syncytial virus (RSV). Parainfluenza virus (PIV) similarly had higher levels of GM-CSF, IL-1b, IL-17A, IL-22 compared with those detected in RSV, influenza B and any other virus infection ( P < 0.05; ANOVA). Increasing age (beta-coefficient = 1.11, 95% CI, 1.04-1.2, P < 0.01) as well as IL-17A levels (beta-coefficient = 1.03, 95% CI, 1.001-1.05, P = 0.04) predicted hospital admission. CONCLUSION: Main Th17 cell effector cytokines were upregulated in laboratory-confirmed A(H3N2) influenza and PIV. Excessive amounts of Th17 cytokines may be implicated in the pathogenesis and immune control of acute influenza and PIV infection in humans and may predict the severity of disease
Delimitsou A, Fostira F, Kalfakakou D, Apostolou P, Konstantopoulou I, Kroupis C, Papavassiliou AG, Kleibl Z, Stratikos E, Voutsinas GE, et al. Functional characterization of CHEK2 variants in a Saccharomyces cerevisiae system. Hum.Mutat. [Internet]. 2019;40(5):631 - 648. WebsiteAbstract
Genetic testing for cancer predisposition leads to the identification of a number of variants with uncertain significance. To some extent, variants of BRCA1/2 have been classified, in contrast to variants of other genes. CHEK2 is a typical example, in which a large number of variants of unknown clinical significance were identified and still remained unclassified. Herein, the CHEK2 variant assessment was performed through an in vivo, yeast-based, functional assay. In total, 120 germline CHEK2 missense variants, distributed along the protein sequence, and two large in-frame deletions were tested, originating from genetic test results in breast cancer families, or selected from the ClinVar database. Of these, 32 missense and two in-frame deletions behaved as non-functional, 73 as functional, and 15 as semi-functional, after comparing growth rates of each strain with positive and negative controls. The majority of non-functional variants were localized in the CHK2 kinase and forkhead-associated domains. In vivo results from the non-functional variants were in agreement with in silico predictions, and, where available, with strong breast cancer family history, to a great extent. The results of the largest, to date, yeast-based assay, evaluating CHEK2 variants, can complement and assist in the classification of rare CHEK2 variants with unclear clinical significance
Economopoulou P, Koutsodontis G, Avgeris M, Strati A, Kroupis C, Pateras I, Kirodimos E, Giotakis E, Kotsantis I, Maragoudakis P, et al. HPV16 E6/E7 expression in circulating tumor cells in oropharyngeal squamous cell cancers: A pilot study. PLoS.One. [Internet]. 2019;14(5):e0215984. WebsiteAbstract
OBJECTIVES: Human papillomavirus-related oropharyngeal squamous cell carcinoma (HPV+ OPSCC) is increasing in incidence. Although HPV+ OPSCC has favorable prognosis, 10 to 25% of HPV+ OPSCCs eventually recur. We sought to evaluate the feasibility of detection of HPV16 E6/E7 expression in Circulating Tumor Cells (CTCs) and its utility as a prognostic tool in HPV16-associated OPSCC. MATERIALS AND METHODS: We developed a highly sensitive RT-qPCR assay for HPV mRNA expression in EpCAM(+) CTCs. In 22 patients with early stage and locally advanced OPSCC we evaluated HPV16 E6/E7 expression in the EpCAM(+) CTC fraction at baseline and at the end of concurrent chemoradiotherapy. HPV status in pre-therapy formalin-fixed paraffin-embedded (FFPE) tumor biopsies was assessed by p16 immunohistochemistry and polymerase chain reaction (PCR) and double positives were subjected to Real-time qPCR assay for detection of HPV16, 18 and 31 types. RESULTS: Fourteen of 22 OPSCC (63.6%) were HPV DNA+/p16+. Among HPV+/p16+ patients, 10 patients (71.4%) were HPV16 DNA+. HPV16 E6/E7(+) CTCs were detected in 3 of 10 patients (30%) at baseline and 4 of 9 patients (44.4%) at the end-of-treatment, all of which were p16+/HPV16 DNA+. Survival analysis showed a significantly higher risk for disease relapse (p = 0.001) and death (p = 0.005) in patients with HPV16 E6/E7(+) baseline CTCs. CONCLUSION: Detection of HPV E6/E7(+) CTCs might be a useful noninvasive test in liquid biopsy samples for determination of a clinically relevant HPV infection in HPV+ OPSCC. Combined interpretation of HPV E6/E7(+) CTCs with UICC staging data may lead to alteration of risk definition of patient subsets, with improved risk discrimination in early-stage disease
Ntzifa A, Kroupis C, Haliassos A, Lianidou E. A pilot plasma-ctDNA ring trial for the Cobas(R) EGFR Mutation Test in clinical diagnostic laboratories. Clin.Chem.Lab Med. [Internet]. 2019;57(5):e97 - e101. Website
Moore KM, Nicholas J, Grossman M, McMillan CT, Irwin DJ, Massimo L, Van Deerlin VM, Warren JD, Fox NC, Rossor MN, et al. Age at symptom onset and death and disease duration in genetic frontotemporal dementia: an international retrospective cohort study. Lancet Neurol. [Internet]. 2019. WebsiteAbstract
BACKGROUND: Frontotemporal dementia is a heterogenous neurodegenerative disorder, with about a third of cases being genetic. Most of this genetic component is accounted for by mutations in GRN, MAPT, and C9orf72. In this study, we aimed to complement previous phenotypic studies by doing an international study of age at symptom onset, age at death, and disease duration in individuals with mutations in GRN, MAPT, and C9orf72. METHODS: In this international, retrospective cohort study, we collected data on age at symptom onset, age at death, and disease duration for patients with pathogenic mutations in the GRN and MAPT genes and pathological expansions in the C9orf72 gene through the Frontotemporal Dementia Prevention Initiative and from published papers. We used mixed effects models to explore differences in age at onset, age at death, and disease duration between genetic groups and individual mutations. We also assessed correlations between the age at onset and at death of each individual and the age at onset and at death of their parents and the mean age at onset and at death of their family members. Lastly, we used mixed effects models to investigate the extent to which variability in age at onset and at death could be accounted for by family membership and the specific mutation carried. FINDINGS: Data were available from 3403 individuals from 1492 families: 1433 with C9orf72 expansions (755 families), 1179 with GRN mutations (483 families, 130 different mutations), and 791 with MAPT mutations (254 families, 67 different mutations). Mean age at symptom onset and at death was 49.5 years (SD 10.0; onset) and 58.5 years (11.3; death) in the MAPT group, 58.2 years (9.8; onset) and 65.3 years (10.9; death) in the C9orf72 group, and 61.3 years (8.8; onset) and 68.8 years (9.7; death) in the GRN group. Mean disease duration was 6.4 years (SD 4.9) in the C9orf72 group, 7.1 years (3.9) in the GRN group, and 9.3 years (6.4) in the MAPT group. Individual age at onset and at death was significantly correlated with both parental age at onset and at death and with mean family age at onset and at death in all three groups, with a stronger correlation observed in the MAPT group (r=0.45 between individual and parental age at onset, r=0.63 between individual and mean family age at onset, r=0.58 between individual and parental age at death, and r=0.69 between individual and mean family age at death) than in either the C9orf72 group (r=0.32 individual and parental age at onset, r=0.36 individual and mean family age at onset, r=0.38 individual and parental age at death, and r=0.40 individual and mean family age at death) or the GRN group (r=0.22 individual and parental age at onset, r=0.18 individual and mean family age at onset, r=0.22 individual and parental age at death, and r=0.32 individual and mean family age at death). Modelling showed that the variability in age at onset and at death in the MAPT group was explained partly by the specific mutation (48%, 95% CI 35-62, for age at onset; 61%, 47-73, for age at death), and even more by family membership (66%, 56-75, for age at onset; 74%, 65-82, for age at death). In the GRN group, only 2% (0-10) of the variability of age at onset and 9% (3-21) of that of age of death was explained by the specific mutation, whereas 14% (9-22) of the variability of age at onset and 20% (12-30) of that of age at death was explained by family membership. In the C9orf72 group, family membership explained 17% (11-26) of the variability of age at onset and 19% (12-29) of that of age at death. INTERPRETATION: Our study showed that age at symptom onset and at death of people with genetic frontotemporal dementia is influenced by genetic group and, particularly for MAPT mutations, by the specific mutation carried and by family membership. Although estimation of age at onset will be an important factor in future pre-symptomatic therapeutic trials for all three genetic groups, our study suggests that data from other members of the family will be particularly helpful only for individuals with MAPT mutations. Further work in identifying both genetic and environmental factors that modify phenotype in all groups will be important to improve such estimates. FUNDING: UK Medical Research Council, National Institute for Health Research, and Alzheimer's Society