Three sons of a normal married couple had congenital immunodeficiency, but their three daughters were not affected. The boys had very low serum IgG levels, and their lymph nodes were devoid of germinal centers

Question

No plasma cells were seen, but T lymphocytes were normal. This condition represents
A. X-linked agammaglobulinemia of Bruton
B. DiGeorge's syndrome
C. adenosine deaminase deficiency
D. severe combined immunodeficiency of Swiss type
E. ataxia-telangiectasia

Answer 1

A
The male members of this kindred are affected by X-linked agammaglobulinemia (XLA), or Bruton's disease. XLA affects only males. The affected boys show signs of immunodeficiency and have very low serum IgG levels or complete agammaglobulinemia combined with a lack of B-lymphocyte maturation in lymph nodes. Pre-B cells are present but do not mature into B lymphocytes or plasma cells. T lymphocytes form normally. The other four immunodeficiency disorders are not inherited as X-linked traits and affect both males and females. DiGeorge's syndrome is a T-cell deficiency related to aplasia or hypoplasia of the thymus. Adenosine deaminase deficiency and other forms of combined immunodeficiency and ataxia-telangiectasia involve both B and T lymphocytes.