The defect in humoral immunity in patients with Nijmegen breakage syndrome is explained by defects in peripheral B lymphocyte maturation.
Cytometry A
; 81(10): 835-42, 2012 Oct.
Article
em En
| MEDLINE
| ID: mdl-22851427
ABSTRACT
Patients with an immunodeficiency in the course of Nijmegen breakage syndrome (NBS) that is caused by mutations in the NBN/NBS1 gene are prone to recurrent infections and malignancies, due to a defective DNA double-strand breaks repair mechanism. Four-color flow cytometry was used to analyze changes in B lymphocyte subsets reflecting the most important stages of peripheral B cell maturation. It was demonstrated that the humoral immune defect observed in NBS patients was caused by reduced numbers of B lymphocytes, but also by their aberrant maturation. Reduced relative and absolute counts of naïve and memory B cells were accompanied by a significant accumulation of the natural effector B lymphocytes. The elevated proportion of IgM-only memory and reduced proportion of IgM-negative cells within the memory B cell pool suggests that there is class-switch recombination defect in this population of cells in NBS patients, resulting in inadequate production of immunoglobulins. Because of the reduced T-cell counts, the T-cell dependent antigen response is severely impaired resulting in a lower frequency of memory B-cells. The T-cell independent B-cell differentiation pathway seems less affected. The reduced IgG and IgA levels in patients with NBS are caused both by ineffective class switch, at least due to poor T cell help, and low number of memory B cells. This study illustrates that the NBN gene product nibrin plays an important role at different levels in the B-cell system.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Nucleares
/
Linfócitos B
/
Subpopulações de Linfócitos B
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Proteínas de Ciclo Celular
/
Síndrome de Quebra de Nijmegen
/
Imunidade Humoral
Limite:
Adolescent
/
Child
/
Child, preschool
/
Humans
/
Infant
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article