Low marginal zone-like B lymphocytes and natural antibodies characterize skewed B-lymphocyte subpopulations in del22q11 DiGeorge patients.
OBJECTIVE
Patients with DiGeorge syndrome suffer from T-lymphopenia. T-cells are important for the maturation and regulation of B-cell function. Our aim was to characterize the B-cell compartment in DiGeorge syndrome patients.


METHODS
B-cell subset phenotypization using flow cytometry. Serum BAFF (B-cell activating factor) and serum anti-alpha-galactosyl IgM measurement using ELISA. Serum IgG measurement using nephelometry.


RESULTS
We observed a significantly increased number of naïve B-cells and decreased number of switched memory B-cells in DiGeorge patients. Furthermore, we observed increased BAFF levels and a trend toward hypergammaglobulinemia later in life. Surprisingly, we detected a decrease in marginal zone-like (MZ-like) B-cells and natural antibodies in DiGeorge patients.


CONCLUSIONS
The maturation of B-cells is impaired in DiGeorge patients, with high naïve and low switched memory B-cell numbers being observed. There is a clear trend toward hypergammaglobulinemia later in life, coupled with increased serum BAFF levels. Surprisingly, the T-independent humoral response is also impaired, with low numbers of MZ-like B-cell and low levels of anti-alpha-galactosyl IgM natural antibodies being detected.
Department of Immunology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic. Electronic address: adam.klocperk@fnmotol.cz.
Adam
A
Klocperk
Childhood Leukemia Investigation Prague, Department of Paediatric Haematology and Oncology, Charles University and University Hospital Motol, Prague, Czech Republic.
Ester
E
Mejstříková
Department of Immunology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic.
Jana
J
Kayserová
Childhood Leukemia Investigation Prague, Department of Paediatric Haematology and Oncology, Charles University and University Hospital Motol, Prague, Czech Republic.
Tomáš
T
Kalina
Department of Immunology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic.
Anna
A
Šedivá
D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000276:immunology*; D053264:B-Cell Activating Factor / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004062:DiGeorge Syndrome / Q000276:immunology*; D005260:Female; D006801:Humans; D006942:Hypergammaglobulinemia / Q000276:immunology; D056724:Immunity, Humoral / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D055815:Young Adult
D000906:Antibodies; D053264:B-Cell Activating Factor; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C505719:TNFSF13B protein, human
B-cells; BAFF; DiGeorge; Marginal zone; Naïve; Switched