Amniocentesis conducted during genetic counseling of a pregnant woman reveals a fetal adenosine deaminase deficiency. This autosomal recessive immunodeficiency is usually associated with which of the following?

Immunodeficiency disorders can be categorized according to whether the defect primarily involves humoral immunity (bone marrow derived, or B lymphocytes) or cellular immunity (thymus derived, or T lymphocytes) or both. Swiss-type hypogammaglobulinemia, ataxia-telangiectasia, the Wiskott-Aldrich syndrome, and severe combined immunodeficiency disorders all involve defective B-cell and T-cell function. Infantile X-linked agammaglobulinemia is caused chiefly by deficient B-cell activity, whereas thymic hypoplasia is mainly a T-cell immunodeficiency disorder.The fetus represented has severe combined immunodeficiency disease (SCID) characterized by defects in early stem cell differentiation. As a result, B cells and T cells are both defective, immunoglobulins are very low, and tonsils and lymph nodes are absent.