Self-organizing maps can determine outcome and match recipients and donors at orthotopic liver transplantation.

BACKGROUND: There is a relative lack of donor organs for liver transplantation. Ideally, to maximize the utility of those livers that are offered, donor and recipient characteristics should be matched to ensure the best possible posttransplant survival of the recipient. METHODS: With prospectively collected data on 827 patients receiving a primary liver graft for chronic liver disease, we used a self-organizing map (SOM) (one form of a neural network) to predict outcome after transplantation using both donor and recipient factors. The SOM was then validated using a data set of 2622 patients undergoing transplantation in the United Kingdom at other centers. RESULTS: SOM analysis using 72 inputs and two survival intervals (3 and 12 months) yielded three neurons with either higher or lower probabilities of survival. The model was validated using the independent data set. With 20 patients on the waiting list and 10 sequential donor livers, it was possible to demonstrate that the model could be used to identify which potential recipients were likely to benefit most from each liver offered. CONCLUSIONS: With this approach to matching donor livers and recipients, it is possible to inform transplant clinicians about the optimum use of donor livers and thereby effectively make the best use of a scarce resource.

Hepatitis B and C virus infections in the immune compromised.

PURPOSE OF REVIEW: This review compares and contrasts the natural history and treatment of hepatitis B and C virus infections in three principal populations of immune compromised individuals: (1) patients co-infected with HIV; (2) patients with liver failure secondary to hepatitis B or C virus infection who undergo liver transplantation, and (3) patients with hepatitis B or C virus infection who undergo anticancer chemotherapy. RECENT FINDINGS: Chronic liver disease resulting from hepatitis B or C virus infection progresses more rapidly in patients co-infected with HIV than in HIV negative patients. Treatment protocols for antiviral therapy are, however, similar to those used in immunocompetent individuals and although few long-term results are available, the efficacy of interferon and ribavirin therapy in hepatitis C virus/HIV infection and lamivudine in HIV/hepatitis B virus infection has been proven in the short-term. Perhaps the most important consideration is the timing of administering treatments to co-infected patients. For patients with well preserved CD4 counts and hepatitis C virus/HIV co-infection, the hepatitis infection should be treated as early as possible to avoid drug interactions of hepatitis C virus antivirals with antiretroviral therapy. Also, response to hepatitis C virus treatment appears better when treatment is administered in the context of preserved immune function. Conversely, in hepatitis B virus/HIV co-infection, hepatitis B virus antivirals are best administered with anti-retroviral therapy, thus preventing the selection of HIV viral species which may be resistant to the drugs used for hepatitis B virus. Improved graft and patient survival after liver transplant and with anticancer chemotherapy in hepatitis B virus infected patients has been proven using lamivudine prophylaxis. However, although therapy for hepatitis C virus recurrence after liver transplantation would seem rational, limited success with current treatment protocols has been achieved. SUMMARY: Although the prognosis of hepatitis B and C virus infections in the immune compromised may be inferior to that of immunocompetent individuals, such patients should have full evaluation of their viral hepatitis, and antiviral therapy should be considered.

Genetically modified interferon: is there a consensus yet?

The treatment of patients with chronic hepatitis C virus infection has evolved during the last decade from interferon monotherapy to combination therapy with interferon and ribavirin. National and international guidelines recommend either 6 or 12 months of interferon/ribavirin combination therapy depending on the pre-treatment virological status of the patient. However, the choice for second-line treatment of patients who do not achieve sustained viral clearance with combination therapy has yet to be defined. This commentary examines previously published studies of the use of consensus interferon for hepatitis C virus infected patients. The characteristics of the treated populations and response to treatment are examined. The current and potential roles for this type of interferon in the treatment of hepatitis C virus infection are considered.