Open AccessDefective expression of the CD40 ligand in X chromosome-linked immunoglobulin deficiency with normal or elevated IgM.
Author(s) -
Ramsay Fuleihan,
Narayanaswamy Ramesh,
Richard Loh,
Haifa H. Jabara,
R S Rosen,
Talal A. Chatila,
Shu Man Fu,
Ivan Stamenkovic,
Raif S. Geha
Publication year - 1993
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.90.6.2170
Subject(s) - immunoglobulin class switching , immunoglobulin d , isotype , cd40 , biology , immunoglobulin e , microbiology and biotechnology , antibody , b cell , immunoglobulin m , immunology , immunoglobulin g , chemistry , monoclonal antibody , genetics , cytotoxic t cell , in vitro
B lymphocytes from patients with X chromosome-linked immunoglobulin deficiency with normal or elevated serum IgM are unable to switch from the synthesis of IgM/IgD to that of other immunoglobulin isotypes. Isotype switch recombination was evaluated in three affected males by examining interleukin 4-driven IgE synthesis. T-cell-dependent IgE synthesis was completely absent in the B lymphocytes of the patients. In contrast, CD40 mAb plus interleukin 4 induced the patients' B cells to synthesize IgE and to undergo deletional switch recombination. Because interaction between CD40 and its ligand on activated T cells is critical for T-cell-driven isotype switching, we examined CD40 ligand expression. In contrast to normal T cells, lymphocytes from the patients expressed no detectable CD40 ligand on their surface after stimulation with phorbol 12-myristate 13-acetate and ionomycin, although the mRNA of the ligand was expressed normally. These results suggest that defective expression of the CD40 ligand underlies the failure of isotype switching in this disease.