A 13-month-old boy is brought to the clinic after repeated infections for the past 4 months, including otitis media, pneumonia, and erysipelas. Although his infections have been responsive to treatment, his father is concerned about the number of infections. The patient also has persistent diarrhea, and a recent stool antigen detection assay was positive for Giardia lamblia. An immunoglobulin panel demonstrates very low serum levels of all immunoglobulin types. Intradermal injection of Candida antigens results in a large indurated nodule within 48 hours. This patient's lymph nodes most likely lack which of the following structures?

Question

A 13-month-old boy is brought to the clinic after repeated infections for the past 4 months, including otitis media, pneumonia, and erysipelas.  Although his infections have been responsive to treatment, his father is concerned about the number of infections.  The patient also has persistent diarrhea, and a recent stool antigen detection assay was positive for Giardia lamblia.  An immunoglobulin panel demonstrates very low serum levels of all immunoglobulin types.  Intradermal injection of Candida antigens results in a large indurated nodule within 48 hours.  This patient's lymph nodes most likely lack which of the following structures?

Quizplus · Accepted Answer

Eductional Objective: X-linked (Bruton) agammaglobulinemia is caused by a defect in B cell maturation, resulting in absent mature B cells and severely low immunoglobulin levels.  T cell numbers and function remain intact.  Due to the absence of B cells, primary lymphoid follicles and germinal centers do not form within lymph nodes.

A 13-Month-Old Boy Is Brought to the Clinic After Repeated