Part of the book: Immunodeficiency
Bruton’s disease, in other terms X-linked agammaglobulinemia (XLA), is the first reported primary immunodeficiency in 1952, caused by a single genetic defect. The development of B cell is under control of signals transmitted by the B-cell antigen receptor (BCR) complex. Lyn, Syk, and Bruton’s tyrosine kinase (BTK) are cytoplasmic protein tyrosine kinases. XLA is caused by mutations in the Btk gene, and Btk mutations are responsible for 85% of all antibody deficiencies. Btk mutation interrupts the B-cell development at the pre-B-cell stage, resulting in the absence of B lymphocytes and plasma cells in peripheral blood and peripheral lymphoid tissues. Up till now, 380 unique mutations have been identified. Autosomal recessive forms of agammaglobulinemia also result in B-cell defects, but more severe bacterial infections are seen in XLA patients due to absolute block in early B-cell development. All serum immunoglobulin isotypes are decreased, and antibody production especially against vaccine antigens is impaired.
Part of the book: Immunopathology and Immunomodulation