Question

A 44-year-old man has been feeling "unwell" the entire week. He complains of anorexia and nausea. On Saturday morning he finds darkening of his urine to a brownish color. His labs confirm the suspicion of acute viral hepatitis. Screening serologic studies for hepatitis A and B virus (HAV, HBV) infections show:

IgM anti-HAV Ab negative
HBV surface Ag positive
IgM anti-HBV core Ab positive
Anti-HBV surface Ab negative

Which of the following mechanisms best explains the hepatic injury?

Direct injury of hepatocyte membranes by viral surface antigen
Inhibition of hepatocyte DNA replication
Inhibition of hepatocyte mRNA translation
Hepatocyte lysis by cytotoxic IgM antibody to viral core antigen
T lymphocyte-mediated lysis of infected hepatic cells
Allergic reaction to the viral proteins

Answer 1

The primary mechanism for hepatic injury in acute viral hepatitis B is the T lymphocyte-mediated lysis of infected liver cells by the immune system. The correct option is E.

Step-by-step explanation:

The hepatic injury in the case of acute viral hepatitis B is primarily caused by the immune system, specifically by T lymphocyte-mediated lysis of infected hepatic cells.

Hepatitis B virus (HBV) infects liver cells (hepatocytes) and results in an inflammatory response. The presence of the HBV surface antigen (HBsAg) indicates active viral replication within hepatocytes. However, the actual damage to the liver is often due to the immune response to the virus rather than the virus itself.

Specifically, the cytotoxic T cells recognize viral antigens presented on the surface of infected hepatocytes and destroy these cells as a means to control the infection.