Auxiliary transplantation for acute liver failure: Histopathological study of native liver regeneration.

Auxiliary liver transplantation (ALT) permits the serial assessment of regeneration in livers of patients with acute liver failure (ALF). Forty-nine ALF patients [32 adults (median age, 23 years; range, 16-40 years) and 17 children (median age, 12 years; range, 1-15 years)] underwent ALT between 1994 and 2004 at King's College Hospital. Twenty-four patients had seronegative liver failure, 15 had acetaminophen toxicity, 4 had hepatitis B virus (HBV) infection, 3 had drug-induced liver failure, 2 had autoimmune hepatitis, and 1 had mushroom poisoning. Nine patients without post-ALT native liver histology were excluded from review. All acetaminophen-induced, HBV, and drug-related patients had diffuse injury. Twelve seronegative patients and the autoimmune hepatitis patient had a map-like injury. On follow-up, 9 acetaminophen-induced patients, 9 seronegative patients, 2 drug-induced ALF patients, 3 HBV patients, and the autoimmune patient recovered to a near-normal native liver with inconsequential scarring. The hepatocyte proliferative rate in diffuse necrosis was 27.4% (range, 3.1%-69.4%) at hepatectomy and sharply decreased after 8 days post-ALT, being minimal months and years after ALT. In conclusion, in patients undergoing ALT for ALF with a diffuse pattern of liver injury-mainly acetaminophen toxicity-hepatocyte proliferation occurs in the native liver within a few days of transplantation. If the injury is map-like (most cases of seronegative ALF), regeneration seems to involve variable hepatocellular proliferation and potential ductular hepatopoiesis, but sequential assessment is difficult because of sampling variation. The likelihood of histological recovery appears to be minimal in livers with total hepatocyte loss at the time of ALT.