Hello Tom
there is a third possibility, all related to HLA class I expression
abnormalities which could ulitmately have several genetic etiologies.
TAP proteins (transporter associated with antigen processing) if mutated
fail to load the Beta 2 class I heavy chain complexes with peptides and as
such these "empty" complexes are very unstable, are inefficiently
transported through the golgi compartment and as a result the class I heavy
chains do not get sialylated and most do not get expressed on the cell
surface. the end result is that CD8+ T cells do not get selected in the
thymus and you end up with few CD8 positive T cells. Another cause of
class-1 deficiency is Beta-2 microglobulin deficiency.
This disorder is referred to as the Type-1 bare lymphocyte syndrome and
you could easilily screen for class I expression by flow cytometry using
any number of available anti-MCH-Class I antibodies.
the reference for the original description of this disorder in 2 family
members is science 265:237-240, 1994.
mo
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Dr. Maurice (Mo) R.G. O'Gorman
Assist. Professor Pediatrics
Northwestern Univ. Med. School
Director Diagnostic Immunology and Flow Cytometry Laboratories
The Children's Memorial Hospital
2300 Children's Plaza
Chicago, IL 60614
Ph. 773 880 3070 office
773 880 4361 laboratory
Fax 773 880 3739
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