Bare lymphocyte syndrome. Consequences of absent class II major histocompatibility antigen expression for B lymphocyte differentiation and function.
The bare lymphocyte syndrome is a rare combined immunodeficiency disorder associated with the absence of class I and/or class II major histocompatibility (MHC) antigens. Although it has been inferred that the immune deficiency is a consequence of disordered MHC-restricted interactions among otherwise normal cells, the biological capabilities and differentiation of B lymphocytes deficient in class II MHC antigens have not been rigorously analyzed. We have examined the phenotypic and functional attributes of B cells with absent class II MHC antigens. Our data demonstrate that these B cells are intrinsically defective in their responses to membrane-mediated activation stimuli. In addition, virtually all the B cells had phenotypic evidence of arrested differentiation at an immature stage. Finally, these B cells also failed to express the C3d-EBV receptor normally present on all B lymphocytes. These data indicate that class II MHC molecules are vital participants in early events of the B cell activation cascade, and that other non-MHC membrane molecules may also be absent as a consequence of either arrested differentiation or as a result of the basic defect affecting the expression of MHC membrane antigens.
Clement
L T
LT
Department of Pediatrics, University of California, Los Angeles School of Medicine 90024.
Plaeger-Marshall
S
S
Haas
A
A
Saxon
A
A
Martin
A M
AM
D000921:Antibody-Producing Cells / Q000276:immunology / Q000473:pathology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000172:deficiency*; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation; D002455:Cell Division; D006681:HLA-D Antigens / Q000172:deficiency*; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D007223:Infant; D008213:Lymphocyte Activation; D008297:Male; D010641:Phenotype
D000944:Antigens, Differentiation, B-Lymphocyte; D006681:HLA-D Antigens