T cell development in a major histocompatibility complex class II-deficient patient

✍ Scribed by Marja C. J. A. Van Eggermond; Ger T. Rijkers; Wietse Kuis; Ben J. M. Zegers; Peter J. van den Elsen

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 976 KB
• Volume: 23
• Category: Article
• ISSN: 0014-2980
• DOI: 10.1002/eji.1830231031

✦ Synopsis

Abstract

In this report we show that the major histocompatibility complex (MHC) class II‐negative thymus of a bare lymphocyte syndrome (BLS) patient contains a reduced CD4^+^ CD8^−^ T cell population when compared to thymocytes derived from a MHC class II‐expressing thymus. Of these CD4^+^ CD8^−^ BLS thymocytes, approximately only one third co‐expressed the CD3 antigen, moreover at a lower expression level when compared to control thymocytes. This suggests a partial maturation of the CD4^+^ CD8^−^ T cells in the absence of MHC class II expression. Among the BLS thymocytes, CD4^+^ CD8^+^ thymocytes could easily be detected. Noteworthy, the number of CD4^−^ CD8^+^ thymocytes was significantly increased. CD4^+^ CD8^−^ T cells could also be found among the BLS peripheral blood mononuclear cells, albeit at reduced numbers. Despite the absence of peripheral MHC class II expression, the majority of these CD4^+^ CD8^−^ T cells co‐expressed the CD45RO marker. In the BLS patient, thymocytes as well as peripheral CD4^+^ CD8^−^ T cells were not restricted in the use of the available T cell receptor (TcR) V gene family pool. However, the lack of detectable levels of thymic and peripheral MHC class II antigen expression in the BLS patient had altered the CD4^−^skewing patterns of TcR V gene families which were present in normal individuals. In conclusion, the lack of MHC class II expression in the BLS patient does not completely inhibit the CD4+ CD8^−^ T cell development.