Bruton’s agammaglobulinemia is due to?
X-Linked agammaglobulinemia of bruton There is defective humoral immunity with normal cell-mediated immunity. It is characterized by the failure of B cell precursors (Pro-B cells and pre B cells) to mature into B cells. There is a mutation in cytoplasmic tyrosine kinase called B - cell tyrosine kinase (BtK).
The disease usually does not become apparent until about age 6 months, when maternal immunoglobulins are depleted.
B cells are absent or markedly decreased in the circulation and the serum levels of all classes of immunoglobulin. There are depletions of B cell area of lymph node (Cortical follicles and medullary cord) and spleen (perifollicular region, germinal centre and mantle layer). Tonsil and adenoids are atrophic
T-cell collection areas are normal i.e.
(i) Paracortical area in lymph nodes, and
(ii) Periarterial lymphoid region & malpighian corpuscle in white pulp of the spleen.
The disease is seen almost entirely in males. There are recurrent bacterial infections of the respiratory tract by H. influenzae, str. pneumonia or staph aureus. There is increased susceptibility to infection with enterovirus (echo, coxsackievirus, poliovirus), Giardia lamblia, and arthritis by mycoplasma
As there is agammaglobulinemia, Opsonization is defective (Immunoglobulins are the major opsonins in the body).
B-cell defect
IgA deficiency
Ig M deficiency
Ig G deficiency