Autoimmune hepatitis: clinical experience after liver transplantation and molecular study using surface plasmon resonance imaging-based strategy

De novo autoimmune hepatitis in patients with HCV recurrence (HCV-€R) after liver transplantation (LT) is of challenging diagnosis and the impact of autoimmune therapy (AT) is still a matter of debate. In the first part of this work the aim was to evaluate clinical, serological, histological characteristics of these patients and the impact of AT. Patients have been evaluated in two European transplant centers .Liver biopsies were retrospectively by experts pathologists. Three parameters, plasma cells infiltrate, interface hepatitis and central vein necrosis, were evaluated applying a new semi-€quantitative method. Final diagnosis was of prevalent viral lesions: HCV-€R, or prevalent immunological lesions: AIH. Forty patients, transplanted between 1983-€2009, were included, 16 (40%) patients were HCV-€R and 24 (60%) AIH. High grade of interface hepatitis and confluent central vein necrosis were significantly more represented in AIH patients, moreover AST/ALT were significantly higher in AIH group (p=0.05 and p=0.003, respectively). No difference was found regarding baseline immunosuppression, autoantibodies and gammaglobulin levels. No relationship between HCV antiviral therapy and AIH was observed. Ten years survival was lower for AIH compared to HCV‐R patients (65%, versus 93%, p=0.050). The AT improved the cytolysis but did not modify long-€term survival (50% treated versus 87.5% non treated patients, p=ns), which was impaired by severe HCV disease progression. Anti-€dsDNA autoantibodies (Abs) are highly diagnostic for systemic lupus erythematosus (SLE), however, they can be found in autoimmune hepatitis (AIH) but it remains uncertain which antigen triggers the production of these antibodies. Moreover the characteristics of antigen‐antibodies interaction are still a matter of concern. In the second part of this work the aim was to differentiate the binding characteristics of dsDNA and anti-€dsDNA Abs obtained from AIH and SLE patient'€™s sera using Surface Plasmon Resonance imaging (SPRi) strategy. Sera from AIH (n=14), SLE patients (n= 7) with anti-€dsDNA Abs positive Farr test, as well as from healthy controls (n= 7) were collected. IgGs and IgMs were purified from sera. Ten different types of oligonucleotides (OG) were spotted over the chip surface of SPRi. Kinetic SPRi study was also performed. All sera from both patients and controls showed a reactivity signal on SPRi, nevertheless when monoclonal mouse anti-€IgGs were injected after the sera injection, only for AIH patients the signal was still evident, being lower for SLE patients and controls. When purified IgGs from sera were injected an interaction signal with OG was observed only for AIH patients. Mean IgGs koff were comparable among patients, meaning they have the same dissociation kinetic. SPRi method identifies interactions between sera from AIH, SLE patients and controls and dsDNA of OG used. However using purified IgGs a binding signal is observed only for AIH. These results suggest that immunocomplex found in AIH and SLE patients are different, in SLE patients the complex might require a third partner, or probably, recognize a specific dsDNA conformation. Results from our work suggest that new promising methods can be applied both in clinical and laboratory field for the comprehension and monitoring of autoimmune hepatitis.