Is the thymus a target organ in infectious diseases?

• Published in: Memórias do Instituto Oswaldo Cruz
• Main Authors: Wilson Savino, Maria do Carmo Leite de Moraes, Suse Dayse Silva Barbosa, Eliene de Carvalho da Fonseca, Vinicius Cotta de Almeida, Mireille Hontebeyrie-Joscowicz
• Format: Article in Journal/Newspaper
• Language: English
• Published: Instituto Oswaldo Cruz, Ministério da Saúde 1992
• Subjects: thymus; thymic microenvironment; thymocytes; infectious diseases; Chagas' disease; schistosomiasis; AIDS; Arctic medicine. Tropical medicine; RC955-962; Microbiology; QR1-502; Arctic
• Online Access: https://doi.org/10.1590/S0074-02761992000900010; https://doaj.org/article/1c8c8d2a40dd4140a0dd3d138fe49489

The thymus is a central lymphoid organ, in wich T cell precursors differentiale and generate most of the so-called T cell reprtoire. Along with a variety of acute infectious diseases, we and others determined important changes in both microenvironmental and lymphoid compartments of the organ. For example, one major and common feature observed in acute viral, bacterial and parasitic diseases, is a depletion of cortical thymocytes, mostly those bearing the CD4-CD8 double positive phenotype. This occurs simmultaneously to the relative enrichment in medullary CD4 or CD8 single positive cells, expressing high densities of the CD3 complex. Additionally we noticed a variety of changes in the thymic microenvironment (and particularly is epithelial component), comprising abnormal location of thymic epithelial cell subsets as well has a denser Ia-bearing cellular network. Moreover, the extracellular matrix network was altered with an intralobular increase of basement membrane proteins that positively correlated with the degree of thymocyte death. Lastly, anti-thymic cell antibodies were detected in both human and animal models of infectious diseases, and in some of them a phenomenon of molecular mimicry could be evidenced. Taken together, the data receiwed herein clearly show that the thymus should be regarded as a target in infectious diseases.