Thymectomy in early childhood: decrease of naive CD4+ T cells and diminished immune response after vaccination
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1
Univeritäts Klinik für Kinder- und Jugendheilkunde, Medizinische Universität Innsbruck, Austria
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2
Department for Hygiene, Mikrobiology and Medical Medicine, Medical University Innsbruck, Austria
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3
Department of Pediatrics, University of Würzburg, Germany
Aims: Our study was aimed to evaluate the influence of thymectomy in early childhood on naive T cell populations, T cell receptor exicion circles (TRECs) and Ki67 expression in thymectomized patients (TP) compared to healthy age matched controls (HC). Further, our study was aimed to compare the immune response to a neo-antigen (tick born encephalitis virus vaccination, TBEV) in TP and HC.
Methods: Flow cytometry data were used to compare naive T cell (CD4+ CD45RA+CD62L+) counts and memory T cell(CD28+CD45RO+) counts of 101 TP and 81 HD. 44 TP and 56 HC were vaccination with TBEV following the Austrian immunization schedule (3 vaccinations at day 0, week 4 and week 48) using FSME Immune junior (Baxter, Vienna, Austria).TBEV specific IgG values and IgG specific avidities were measured 4 weeks after the second and third vaccination as well as two years after the third vaccination using a commercially available ELISAs.
Results: TP showed significantly lower values according to naive T cells (p<0.001) and lower TRECs (p<0.001) compared to HC. TREC counts showed a significant correlation with ongoing time after thymectomy (p<0.001). TP showed a higher percentage of Ki67+ naive T cells compared to HC (p<0.01).
Four weeks after the second TBEV vaccination significantly lower TBEV specific IgG values were detected in TP when compared to HC (p<0.05). Two years after the second vaccinations TP showed similar IgG values and IgG specific avidities compared to HC.
Conclusion: Out study revealed that TP showed alterations in the peripheral T cell subpopulations similar to findings in elderly people with immunosenescence after physiological thymic involution. TP showed higher peripheral naive T cell proliferation.
TP showed a diminished immune response to TBEV vaccination but a normal memory function of the immune system. Whether these alterations found after childhood thymectomy play a role for age-associated disease in later life of these patients have to be awaited.
Keywords:
Thymectomy,
immunosenescence,
TBEV,
Vaccination,
naive T cells
Conference:
15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013.
Presentation Type:
Abstract
Topic:
Adaptive Immunity
Citation:
Zlamy
M,
Goegele
C,
Würzner
R,
Geiger
R and
Prelog
M
(2013). Thymectomy in early childhood: decrease of naive CD4+ T cells and diminished immune response after vaccination.
Front. Immunol.
Conference Abstract:
15th International Congress of Immunology (ICI).
doi: 10.3389/conf.fimmu.2013.02.00562
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Received:
11 Jun 2013;
Published Online:
22 Aug 2013.
*
Correspondence:
Dr. Manuela Zlamy, Univeritäts Klinik für Kinder- und Jugendheilkunde, Medizinische Universität Innsbruck, Innsbruck, Austria, M.zlamy@gmx.at