A 18-month old boy is brought to the physician’s office by his parents for evaluation of recurrent nosebleeds. In the past year, he has had four respiratory infections and three episodes of otitis media. Past medical history is otherwise unremarkable, and he does not currently take any medications. His immunizations are up to date. He is at the 4th percentile for both height and weight. His vital signs are within normal limits. Cardiopulmonary examination shows no abnormalities. There are dry, scaly white lesions on his forehead, cheeks, and elbows.
Which of the following laboratory findings would most likely be present in this patient?
C) Increased IgE
Male patients with thrombocytopenia, eczematous skin lesions, and recurrent infections are suspected to have Wiskott-Aldrich syndrome (WAS), an X-linked recessive immunodeficiency disorder. Patients with WAS have a defect in the WAS protein, which is important in the organization of cytoskeletons in lymphocytes and platelets. Thrombocytopenia will cause increased bleeding, and impaired T-cell function will lead to abnormal immunoglobulin isotypes and recurrent infections. WAS patients are observed to have elevated IgA and IgE levels, resulting in eczema, and decreased IgG and IgM.
Answer choice A: Decreased IFN-y, is incorrect. Decreased IFN-y points to IL-12 receptor deficiency, a congenital T-cell immunodeficiency that presents with severe mycobacterial and fungal infections.
Answer choice B: Decreased IgA, is incorrect. Patients with WAS present with increased IgA, not decreased IgA.
Answer choice D: Increased IgG, is incorrect. Patients with WAS have decreased IgG levels.
Answer choice D: Increased IgM, is incorrect. Hyper-IgM syndrome is caused by a deficiency of CD40L in CD4+ T-cells, which leads to a defect in class switching from IgM to other immunoglobulins. Thus, Hyper-IgM syndrome will show increased serum IgM and will present with severe pyogenic, viral, and fungal infections early in life.
Key Learning Point
Wiskot-Aldrich syndrome presents with the classic triad of recurrent infections, bleeding caused thrombocytopenia, and eczema. It is also associated with increased IgE and IgA levels and decreased IgG and IgM levels.
