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Georg Wick - One of the best experts on this subject based on the ideXlab platform.
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altered switch in lipid composition during t cell blast transformation in the healthy elderly
Journals of Gerontology Series A-biological Sciences and Medical Sciences, 1995Co-Authors: Thomas M Stulnig, Dieter Schönitzer, Ernst Biihler, Giinther Bock, Charita Kirchebner, Georg WickAbstract:Decreased Mitogen responsiveness of lymphocytes during aging correlates inversely with membrane microviscosity, which reflects an altered lipid composition. Therefore, we addressed the question, whether age-related alterations of lipid metabolism affect the switch in lipid composition during formation of blasts. Membrane lipids and fatty acids of peripheral blood lymphocytes from SENIEUR protocol compatible ("healthy") elderly donors (66-77 yr) and young controls (18-30 yr) were quantified after incubation with or without the Mitogen phytohaemagglutinin. The blastic change in membrane lipid composition was different for young controls with respect to cholesterol, phosphatidylethanolamine, total phospholipids, as well as several fatty acids. Moreover, the age-related alterations in the switch of membrane lipids and fatty acids were significantly correlated with a decreased Mitogen Response. Thus, the alterations in membrane reorganization during blast formation of lymphocytes from the elderly point to a disturbed cellular lipid homeostasis with possible impact on the age-related reduction in immune function.
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Correlation of lymphocyte lipid composition membrane microviscosity and Mitogen Response in the aged.
European journal of immunology, 1991Co-Authors: Lukas A. Huber, Günther Jürgens, Günther Böck, Ernst Bühler, K. Fred Gey, Dieter Schönitzer, Karine N. Traill, Georg WickAbstract:Healthy aged and young blood donors were investigated for the role of membrane lipid composition in the age-related increase in membrane microviscosity and decline of Mitogen responsiveness. Membrane microviscosity was shown to correlate positively with membrane cholesterol/phospholipid molar ratios, which were significantly elevated in the elderly. A positive correlation also was confirmed between lymphocyte membrane microviscosity, which was measured using the probe 1,6-diphenyl 1,3,5-hexatriene, and phytohemagglutinin responsiveness of cells from the same donor. Using stepwise regression statistical analysis, the variables age, cholesterol, cholesterol/total phospholipid and phosphatidyl ethanolamine/phosphatidyl choline molar ratios were all shown to have a significant positive influence on membrane microviscosity, whereas total phospholipids had a negative effect. No statistically significant difference was seen in content of any single saturated or unsaturated fatty acid between young and old donors. After pooling, however, the proportion of all unsaturated fatty acids was significantly higher in cells from the elderly as a consequence of an increase of n-6 and n-3 polyunsaturated fatty acids. Changes in lipid composition and physical properties of lymphocyte plasma membranes may, therefore, be responsible (at least partially) for the diminution of immune reactivity in old age.
Gerald H Mazurek - One of the best experts on this subject based on the ideXlab platform.
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unusual interferon gamma measurements with quantiferon tb gold and quantiferon tb gold in tube tests
PLOS ONE, 2011Co-Authors: Richard Powell, William C Whitworth, John Bernardo, Patrick K Moonan, Gerald H MazurekAbstract:Introduction: Interferon gamma (IFN-c) release assays, such as QuantiFERONH-TB Gold test (QFT-G) and QuantiFERONH-TB Gold In-Tube test (QFT-GIT) are designed to detect M. tuberculosis (Mtb) infection. Recognition of unusual IFN-c measurements may help indicate inaccurate results. Methods: We examined QFT-G and QFT-GIT results from subjects who had two or more tests completed. We classified unusual IFN-c measurements as: 1) High Nil Concentration (HNC) when IFN-c concentration in plasma from unstimulated blood exceeded 0.7 IU/mL; 2) Low Mitogen Response (LMR) when Mitogen Response was ,0.5 IU/mL; 3) Very Low Mitogen Response (VLMR) when Mitogen Response was #20.5 IU/mL; and 4) Very Low Antigen Response (VLAR) when the Response to a Mtb antigen was #20.35 IU/mL and #20.5 times the IFN-c concentration in plasma from unstimulated blood. Results: Among 5,309 results from 1,728 subjects, HNC occurred in 234 (4.4%) tests for 162 subjects, LMR in 108 (2.0%) tests for 85 subjects, VLMR in 22 (0.4%) tests for 21 subjects, and VLAR in 41 (0.8%) tests for 39 subjects. QFT-GIT had fewer HNC, VLMR, and VLAR (p=0.042, 0.004, and 0.067 respectively); QFT-G had fewer LMR (p=0.005). Twenty-four (51.6%) of 47 subjects with positive results and HNC were negative or indeterminate by all other tests. Thirteen (61.9%) of 21 subjects with positive results and LMR were negative or indeterminate by all other tests. Conclusion: Unusual IFN-c measurements including HNC, LMR, VLMR, and VLAR were encountered in small numbers, and in most instances were not seen on simultaneously or subsequently performed tests. To avoid erroneous diagnosis of Mtb infection, IGRAs with unusual IFN-c measurements should be repeated with another blood sample and interpreted with caution if they recur.
Dieter Schönitzer - One of the best experts on this subject based on the ideXlab platform.
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altered switch in lipid composition during t cell blast transformation in the healthy elderly
Journals of Gerontology Series A-biological Sciences and Medical Sciences, 1995Co-Authors: Thomas M Stulnig, Dieter Schönitzer, Ernst Biihler, Giinther Bock, Charita Kirchebner, Georg WickAbstract:Decreased Mitogen responsiveness of lymphocytes during aging correlates inversely with membrane microviscosity, which reflects an altered lipid composition. Therefore, we addressed the question, whether age-related alterations of lipid metabolism affect the switch in lipid composition during formation of blasts. Membrane lipids and fatty acids of peripheral blood lymphocytes from SENIEUR protocol compatible ("healthy") elderly donors (66-77 yr) and young controls (18-30 yr) were quantified after incubation with or without the Mitogen phytohaemagglutinin. The blastic change in membrane lipid composition was different for young controls with respect to cholesterol, phosphatidylethanolamine, total phospholipids, as well as several fatty acids. Moreover, the age-related alterations in the switch of membrane lipids and fatty acids were significantly correlated with a decreased Mitogen Response. Thus, the alterations in membrane reorganization during blast formation of lymphocytes from the elderly point to a disturbed cellular lipid homeostasis with possible impact on the age-related reduction in immune function.
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Correlation of lymphocyte lipid composition membrane microviscosity and Mitogen Response in the aged.
European journal of immunology, 1991Co-Authors: Lukas A. Huber, Günther Jürgens, Günther Böck, Ernst Bühler, K. Fred Gey, Dieter Schönitzer, Karine N. Traill, Georg WickAbstract:Healthy aged and young blood donors were investigated for the role of membrane lipid composition in the age-related increase in membrane microviscosity and decline of Mitogen responsiveness. Membrane microviscosity was shown to correlate positively with membrane cholesterol/phospholipid molar ratios, which were significantly elevated in the elderly. A positive correlation also was confirmed between lymphocyte membrane microviscosity, which was measured using the probe 1,6-diphenyl 1,3,5-hexatriene, and phytohemagglutinin responsiveness of cells from the same donor. Using stepwise regression statistical analysis, the variables age, cholesterol, cholesterol/total phospholipid and phosphatidyl ethanolamine/phosphatidyl choline molar ratios were all shown to have a significant positive influence on membrane microviscosity, whereas total phospholipids had a negative effect. No statistically significant difference was seen in content of any single saturated or unsaturated fatty acid between young and old donors. After pooling, however, the proportion of all unsaturated fatty acids was significantly higher in cells from the elderly as a consequence of an increase of n-6 and n-3 polyunsaturated fatty acids. Changes in lipid composition and physical properties of lymphocyte plasma membranes may, therefore, be responsible (at least partially) for the diminution of immune reactivity in old age.
Piero Valentini - One of the best experts on this subject based on the ideXlab platform.
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accuracy of quantiferon tb gold test for tuberculosis diagnosis in children
PLOS ONE, 2015Co-Authors: Michela Sali, Danilo Buonsenso, Delia Goletti, Pamela Dalfonso, Antonella Zumbo, Giovanni Fadda, Maurizio Sanguinetti, Giovanni Delogu, Piero ValentiniAbstract:Objectives To evaluate the accuracy of the QuantiFERON-TB Gold assay (QFT-IT) in children with suspected active or latent TB infection (LTBI). Methods A retrospective study was conducted on 621 children (0–14 years old) evaluated for TB infection or disease. Following clinical assessment, children were tested with the QFT-IT assay. Results Among the 140 active TB suspects, we identified 19 cases of active disease. The overall sensitivity for active TB was 87.5%, ranging from 62.5% in children 25–36 months old to 100% in children older than 49 months. The overall specificity for active TB was 93.6%. Among the 481 children tested for LTBI screening, 38 scored positive and all but 2 had at least one risk factor for TB infection. Among the 26 children with indeterminate results, bacterial, viral or fungal pneumonia were later diagnosed in 11 (42.3%) cases and non-TB related extra-pulmonary infections in 12 (46.1%). Conclusions Our results indicate that the children's Response to QFT-IT associates to active TB and risk factors for LTBI. Moreover, we show that Mitogen Response is also found in children of 1 year of age, providing support for QFT-IT use also in young children.
Pernille Ravn - One of the best experts on this subject based on the ideXlab platform.
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latent tuberculosis in hiv positive diagnosed by the m tuberculosis specific interferon γ test
Respiratory Research, 2006Co-Authors: Inger Brock, Morten Ruhwald, Bettina Lundgren, Henrik Westh, Lars Mathiesen, Pernille RavnAbstract:Background: Although tuberculosis (TB) is a minor problem in Denmark, severe and complicated cases occur in HIV positive. Since the new M. tuberculosis specific test for latent TB, the QuantiFERON-TB In-Tube test (QFT-IT) became available the patients in our clinic have been screened for the presence of latent TB using the QFT-IT test. We here report the results from the first patients screened. Methods: On a routine basis the QFT-IT test was performed and the results from 590 HIV positive individuals consecutively tested are presented here. CD4 cell count and TB risk-factors were recorded from patient files. Main findings: 27/590(4.6%) of the individuals were QFT-IT test positive, indicating the presence of latent TB infection. Among QFT-IT positive patients, 78% had risk factors such as long-term residency in a TB high endemic area (OR:5.7), known TB exposure (OR:4.9) or previous TB disease (OR:4.9). The prevalence of latent TB in these groups were 13%, 16% and 19% respectively. There was a strong correlation between low CD4 T-cell count and a low Mitogen Response (P < 0.001;Spearman) and more patients with low CD4 cell count had indeterminate results. Conclusion: We found an overall prevalence of latent TB infection of 4.6% among the HIV positive individuals and a much higher prevalence of latent infection among those with a history of exposure (16%) and long term residency in a high endemic country (13%). The QFT-IT test may indeed be a useful test for HIV positive individuals, but in severely immunocompromised, the test may be impaired by T-cell anergy.