You Are Treating a 4-Year-Old Child Who Has Been Afflicted

You are treating a 4-year-old child who has been afflicted with recurrent infections. The child exhibits retarded development, weakness, and weight loss. Physical examination also shows absent tonsils and blood work reveals a lack of lymphocytes. These signs and symptoms are typical of severe combined immunodeficiency syndrome. Which of the following compounds would be expected to be elevated in the blood of this patient?

A) bilirubin
B) cytosine
C) deoxyadenosine
D) deoxythymidine
E) xanthine