@article{ZlamyAlmanzarParsonetal.2016, author = {Zlamy, Manuela and Almanzar, Giovanni and Parson, Walther and Schmidt, Christian and Leierer, Johannes and Weinberger, Birgit and Jeller, Verena and Unsinn, Karin and Eyrich, Matthias and W{\"u}rzner, Reinhard and Prelog, Martina}, title = {Efforts of the human immune system to maintain the peripheral CD8+ T cell compartment after childhood thymectomy}, series = {Immunity \& Ageing}, volume = {13}, journal = {Immunity \& Ageing}, number = {3}, doi = {10.1186/s12979-016-0058-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146497}, year = {2016}, abstract = {Background Homeostatic mechanisms to maintain the T cell compartment diversity indicate an ongoing process of thymic activity and peripheral T cell renewal during human life. These processes are expected to be accelerated after childhood thymectomy and by the influence of cytomegalovirus (CMV) inducing a prematurely aged immune system. The study aimed to investigate proportional changes and replicative history of CD8+ T cells, of recent thymic emigrants (RTEs) and CD103+ T cells (mostly gut-experienced) and the role of Interleukin-(IL)-7 and IL-7 receptor (CD127)-expressing T cells in thymectomized patients compared to young and old healthy controls. Results Decreased proportions of naive and CD31 + CD8+ T cells were demonstrated after thymectomy, with higher proliferative activity of CD127-expressing T cells and significantly shorter relative telomere lengths (RTLs) and lower T cell receptor excision circles (TRECs). Increased circulating CD103+ T cells and a skewed T cell receptor (TCR) repertoire were found after thymectomy similar to elderly persons. Naive T cells were influenced by age at thymectomy and further decreased by CMV. Conclusions After childhood thymectomy, the immune system demonstrated constant efforts of the peripheral CD8+ T cell compartment to maintain homeostasis. Supposedly it tries to fill the void of RTEs by peripheral T cell proliferation, by at least partly IL-7-mediated mechanisms and by proportional increase of circulating CD103+ T cells, reminiscent of immune aging in elderly. Although other findings were less significant compared to healthy elderly, early thymectomy demonstrated immunological alterations of CD8+ T cells which mimic features of premature immunosenescence in humans.}, language = {en} } @article{WagnerDrouetTeschnerWolschkeetal.2021, author = {Wagner-Drouet, Eva and Teschner, Daniel and Wolschke, Christine and Sch{\"a}fer-Eckart, Kerstin and G{\"a}rtner, Johannes and Mielke, Stephan and Schreder, Martin and Kobbe, Guido and Hilgendorf, Inken and Klein, Stefan and Verbeek, Mareike and Ditschkowski, Markus and Koch, Martina and Lindemann, Monika and Schmidt, Traudel and Rascle, Anne and Barabas, Sascha and Deml, Ludwig and Wagner, Ralf and Wolff, Daniel}, title = {Comparison of cytomegalovirus-specific immune cell response to proteins versus peptides using an IFN-γ ELISpot assay after hematopoietic stem cell transplantation}, series = {Diagnostics}, volume = {11}, journal = {Diagnostics}, number = {2}, issn = {2075-4418}, doi = {10.3390/diagnostics11020312}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228843}, year = {2021}, abstract = {Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT). Measuring CMV-specific cellular immunity may improve the risk stratification and management of patients. IFN-γ ELISpot assays, based on the stimulation of peripheral blood mononuclear cells with CMV pp65 and IE-1 proteins or peptides, have been validated in clinical settings. However, it remains unclear to which extend the T-cell response to synthetic peptides reflect that mediated by full-length proteins processed by antigen-presenting cells. We compared the stimulating ability of pp65 and IE-1 proteins and corresponding overlapping peptides in 16 HSCT recipients using a standardized IFN-γ ELISpot assay. Paired qualitative test results showed an overall 74.4\% concordance. Discordant results were mainly due to low-response tests, with one exception. One patient with early CMV reactivation and graft-versus-host disease, sustained CMV DNAemia and high CD8\(^+\) counts showed successive negative protein-based ELISpot results but a high and sustained response to IE-1 peptides. Our results suggest that the response to exogenous proteins, which involves their uptake and processing by antigen-presenting cells, more closely reflects the physiological response to CMV infection, while the response to exogenous peptides may lead to artificial in vitro T-cell responses, especially in strongly immunosuppressed patients.}, language = {en} }