Progress in developing animal models for biliary atresia.

Animal models for extrahepatic biliary atresia (EHBA) have failed to simulate the course of the disease. Until now only a few aspects of the entity could be investigated and no model was helpful in discovering the etiology of EHBA. Following the suspicion of a viral and hepatotropic infection, investigations in an infectious mouse model were continued. The results of previous and topical studies are summarized here. Infection of newborn Balb/c-mice with rhesus rotavirus (RRV) leads to cholestasis in 85% of the animals followed by a lethality of 90%. Preparation and histomorphological investigation of liver and ligamentum duodenale reveal EHBA of varying extent. Clinical course and morphological findings in mice are very similar to EHBA in newborn children and the results are presented in a chronological table. Hepatobiliary morbidity and lethality after RRV infection is higher in Balb/c-mice than in other mouse strains. This observation supports the suspicion that immunocompetence might be a determining factor in the etiology of EHBA. Initial therapeutic trials were made using this model by treating infected newborn mice with interferon-alpha (IFN). The prophylactic application of IFN protects the infected mice from cholestatic symptoms and appears to induce partial immunity. Their descendants are protected against the hepatotropic effect of RRV infection. Infected animals presenting with clinical signs of cholestasis can be treated successfully by IFN-therapy for one week. In the presented animal model. EHBA can be better induced and simulated than by any other method. As a first trial, a non-surgical and more etiologically orientated therapeutic method is tested in this model.

Treatment of anti-recombinant interferon-alpha 2 antibody positive CML patients with natural interferon-alpha.

Of 38 patients with a Philadelphia-chromosome positive chronic myeloid leukaemia treated with recombinant interferon alpha (rIFN-alpha) 2a or 2b and monitored for emergence of IFN-antibodies in their sera 11 patients developed rIFN-alpha 2 binding and 10 rIFN-alpha 2 neutralizing antibodies. rIFN-alpha neutralizing antibody positive patients experienced significantly (P less than 0.025) more clinical relapses (6/10) than IFN-antibody negative patients (6/28) during continuous IFN-therapy. Furthermore, IFN-antibody-positive patients with titre above 400 INU/ml were more likely to relapse under rIFN-alpha-therapy than IFN-antibody-negative patients with titre below 400 INU/ml (P less than 0.05). Seven rIFN-antibody-positive patients experiencing a clinical relapse or a primary non-responsiveness were treated with two- to three-fold increased doses of rIFN-alpha 2. Only one of these seven patients developed a partial haematological remission upon intensification of the rIFN-alpha 2 therapy. Consecutively, the six patients failing high dose rIFN-alpha treatment were switched to a natural IFN-alpha preparation (3 x 9 x 10(6) I.U. weekly s.c.). Under such treatment two of the six patients achieved a long-lasting complete, one a partial haematological remission. In high-titred IFN-antibody positive patients significantly altered serum-IFN-titre and minimal IFN-inducible Mx-homologue concentrations were measured; in contrast, nIFN-alpha induced normal IFN-titre and dose-equivalent Mx-homologue amounts in these patients. The data prove that high-titred rIFN-alpha neutralizing antibodies abrogate the biological action of rIFN-alpha, but not of nIFN-alpha in vivo and explains why nIFN-alpha can be effective in the anti rIFN-alpha 2 positive patients.