A 35-year-old man is found to have elevated alanine aminotransferase and aspartate aminotransferase levels. He has no abdominal pain, nausea, or vomiting. The patient has used intravenous drugs in the past but denies significant alcohol use. His past medical history is negative for blood transfusions or excessive acetaminophen use. Physical examination findings are normal. Laboratory studies show high titers of IgG directed against the hepatitis C envelope protein. Which of the following is the most likely reason that these antibodies do not confer effective immunity against the infection?

Question

A 35-year-old man is found to have elevated alanine aminotransferase and aspartate aminotransferase levels.  He has no abdominal pain, nausea, or vomiting.  The patient has used intravenous drugs in the past but denies significant alcohol use.  His past medical history is negative for blood transfusions or excessive acetaminophen use.  Physical examination findings are normal.  Laboratory studies show high titers of IgG directed against the hepatitis C envelope protein.  Which of the following is the most likely reason that these antibodies do not confer effective immunity against the infection?

Quizplus · Accepted Answer

Eductional Objective: Genetic variations created during hepatitis C virus (HCV) replication result in marked variety in the antigenic structure of HCV envelope proteins.  The production of host antibodies lags behind that of new mutant HCV strains, preventing infected individuals from mounting an effective immune response.

A 35-Year-Old Man Is Found to Have Elevated Alanine Aminotransferase