Mcja. Vaneggermond et al., T-CELL DEVELOPMENT IN A MAJOR HISTOCOMPATIBILITY COMPLEX CLASS II-DEFICIENT PATIENT, European Journal of Immunology, 23(10), 1993, pp. 2585-2591
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 thymoc
ytes derived from a MHC class II-expressing thymus. Of these CD4+ CD8-
BLS thymocytes, approximately only one third co-expressed the CD3 ant
igen, moreover at a lower expression level when compared to control th
ymocytes. This suggests a partial maturation of the CD4+ CD8- T cells
in the absence of MHC class II expression. Among the BLS thymocytes, C
D4+ CD8+ thymocytes could easily be detected. Noteworthy, the number o
f 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 t
he 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 c
ell receptor (TcR) V gene family pool. However, the lack of detectable
levels of thymic and peripheral MHC class Il antigen expression in th
e BLS patient had altered the CD4-skewing patterns of TcR V gene famil
ies which were present in normal individuals. In conclusion, the lack
of MHC class II expression in the BLS patient does not completely inhi
bit the CD4+ CD8- T cell development.