lab - okt3

[ArchivalUser]

A 42-year-old man has lost 7 kg over the past two years. During that time he has had pain and swelling around the small joints of his hands and feet. He has had a series of upper respiratory tract infections, with organisms including Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa cultured. He has a chronic diarrhea. A stool specimen is found to have Giardia lamblia cysts. Laboratory studies show a hemoglobin of 8.8 g/dL with a reticulocyte count of 3.2%. His serum urea nitrogen is 19 mg/dL with creatinine 1.0 mg/dL. His antinuclear antibody test is negative. Quantitative serum immunoglobulins show IgA 70 mg/dL, IgG 303 mg/dL, and IgM 64 mg/dL. By flow cytometry there are normal numbers of T cells and slightly reduced numbers of B cells. Which of the following conditions is most likely to be present in this man?

A HIV infection

B Polymyositis

C Bruton agammaglobulinemia

D Common variable immunodeficiency

E Diabetes mellitus

[ArchivalUser]

D Common variable immunodeficiency

[ArchivalUser]

D!

[ArchivalUser]

dd

[ArchivalUser]

D) CORRECT. He has common variable immunodeficiency, with hypogammaglobulinemia that predisposes him to bacterial infections and also Giardia. Patients can have rheumatoid arthritis and hemolytic anemia. Most patients have normal to slightly reduced numbers of B lymphocytes that cannot differentiate into immunoglobulin-secreting plasma cells