De Novo Autoimmune Hepatitis in Pediatric Liver Transplantation

De Novo Autoimmune Hepatitis in Pediatric Liver Transplantation

The purpose of this study is to provide insights into the cause, development and effects of de novo autoimmune hepatitis so that prevention and treatment strategies can be developed in order to reduce post-liver transplant morbidity, the frequency of liver allograft loss and the need for re-transplantation.

This is a multi-site study with Yale University as the coordinating site. Our research plan is as follows:

Aim 1: To conduct a refined phenotypical and functional analysis of regulatory T cells in study and control patient groups.

Rationale: We would like to extend our preliminary data observations in a larger patient group and use this extended data set to conduct a refined phenotypical and functional analysis of regulatory T cells in order to explore if the regulatory T cell phenotype and function in d-AIH differs: (A) from that in controls defined as (i) non-transplanted patients with autoimmune hepatitis (AIH), (ii) LT recipients with acute rejection, (iii) LT recipients with chronic rejection, (iv) non-transplanted patients with chronic hepatitis C; (B) according to the disease etiology leading to transplantation; (C) according to immunosuppressive regimen prior to diagnosis of d-AIH being made and (D) over time during the disease course. This could potentially give us some insight into the causes for immune tolerance breakdown in d-AIH.

Aim 2: To investigate how over expression of IL-17A and HDAC9 genes relates to the regulatory T cell defect observed in liver transplant recipients with d-AIH.

Rationale: Histone/protein deacetylases regulate chromatin remodeling, gene expression and the functions of many transcription factors. Acetylation of histones leads to an open chromatin structure permissive for the initiation of gene transcription and expression. Histone deacetylase inhibition by Trichostatin-A (TSA) has been demonstrated to prevent the production of IL-17A and sustain Foxp3 expression in human T-regs. Importantly, if differentiation of T-regs into a Th17-like phenotype can be inhibited by TSA in d-AIH, this might be of interest for the development of new therapeutic modalities.

We would like to first of all confirm our preliminary data observations in a larger patient population and address any concerns about RNA integrity in formalin fixed paraffin embedded tissue by using fresh liver biopsy tissue to assess the expression of genes involved in T-cell anergy and immune tolerance in LT recipients.

Inclusion Criteria:

Pediatric Transplant Patients

• Is >3-months and <21 years of age and a recipient of a single organ liver transplant
• Has allograft dysfunction (an ALT and/or GGTP > 2 times the upper limit of normal) due to acute rejection without a prior diagnosis of d-AIH
• Has allograft dysfunction (an ALT and/or GGT > 2 times the upper limit of normal) due to chronic rejection without a prior diagnosis of d-AIH
• Has a diagnosis of d-AIH

Healthy Pediatric Control Subjects (Enrolled at Yale)

• Is ≥ 1-year and < 18-years of age
• Not on any immune modulators
• Not on steroid therapy
• Has no underlying chronic inflammatory condition

Adult Control Subjects (Enrolled at Yale) Non-transplanted Adult patients with autoimmune hepatitis and chronic hepatitis C will also be enrolled.

• Non-transplanted adults "18 Years or > " with Autoimmune Hepatitis
• Non-transplanted adults "18 Years or > " with chronic hepatitis C who are treatment naive.

Exclusion Criteria:

Pediatric Transplant Patients - Multi-visceral organ transplant recipient

Healthy Pediatric Control Subjects (Enrolled at Yale)

• <1-year and > 18-years of age
• Has chronic inflammatory condition
• On immune modulators or steroids
• On chronic medication(s)

Adult transplanted patients with d-AIH (enrolled at Yale)

- Transplanted Adults ≥21-years of age with a diagnosis of d-AIH