Asymptomatic deficiency in the peptide transporter associated to antigen processing (TAP).
Clin Exp Immunol
; 128(3): 525-31, 2002 Jun.
Article
in En
| MEDLINE
| ID: mdl-12067308
ABSTRACT
Human HLA class I deficiency is a rare disease which, in most of the patients described to date, results from a defect in subunit 1 or 2 of the peptide transporter associated with antigen processing (TAP). The clinical features of TAP deficiency include a chronic inflammation of the respiratory tract and/or granulomatous skin lesions. In this report, we describe two adult siblings with an HLA class I deficiency. One individual had only spontaneously-healing skin granulomatous lesions, while the second did not display any of the symptoms associated with HLA class I deficiency and could be considered to be healthy. We show that the patients display a homozygous TAP2 mutation which blocks the maturation of HLA class I molecules. Cell surface expression of these molecules is strongly reduced, but three times higher than on cells from other previously described TAP-deficient individuals. This higher expression results, at least in part, from the presence of HLA-B7 molecules which are probably empty of peptide. The numbers of CD8+ alphabeta T cells are almost normal in these patients. The anti-EBV T-cell response of one patient is mediated by HLA-B7 restricted CD8+ alphabeta T lymphocytes recognizing the BMRF1 nuclear EBV antigen, demonstrating that CD8+ alphabeta T cells can participate in anti-viral responses. This study shows that TAP deficiency can remain totally asymptomatic for several decades, and suggests that in some cases, TAP-independent immune responses provide efficient protection from most of the common intracellular pathogens.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Histocompatibility Antigens Class I
/
Gene Deletion
/
ATP-Binding Cassette Transporters
Type of study:
Risk_factors_studies
Limits:
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Clin Exp Immunol
Year:
2002
Document type:
Article
Affiliation country:
Francia