The goal of this observational study is to to identify different causes of liver diseases or damage in liver transplant patients and develop a machine learning algorithm as a non-invasive tool leveraging gene expression and patient clinical information to classify transplant liver diseases We will collect blood samples of the participants who had undergone or will undergo the liver biopsy as part of standard of care, and use this blood in TruGarf. TruGraf is a non-invasive test that measures differentially expressed genes in the blood of transplant recipients to rule out liver damage. Researcher will collect the biopsy result from the medical record and this will be compared with the TruGarf results.

Given the significant investment of healthcare resources into transplantation, it is critical to identify recipients with graft pathologies such as Acute Cellular Rejection (ACR), NASH, cholestasis, etc. at an earlier stage to implement the appropriate intervention, rather than initiating empiric treatment that could be unsafe. This project will develop a practical Machine learning-based tool based on the results of the TruGraf assay alongside clinical and laboratory data for non-invasive diagnosis of graft pathology. TruGraf is a non-invasive test that measures differentially expressed genes in the blood of transplant recipients to identify patients who are likely to be adequately immunosuppressed and, in doing so, rule out graft damage. TruGraf measures the difference in gene expression for a precise panel of specific genes that have been empirically determined to discriminate between allografts that are truly healthy (Non-ACR), and those in transplant patients that have acute rejection on biopsy (AR). Nevertheless, the exact etiology of graft damage may be difficult to discern for the transplant clinician. The clinical characteristics and history of the liver transplant recipient as well as liver enzyme patterns can provide a pre-test probability of one diagnosis being more likely than the other (Acute cellular rejection, NASH, biliary or viral disease). The proposed tool will leverage our expertise in Machine Learning tools applied to clinical and molecular data (TruGraf assay results) to enable effective clinical implementation of the TruGraf assay.

Inclusion Criteria:

1. . Single-organ Liver transplant recipients
2. Male or female, age > 18 years at the time of signing informed consent.
3. Willing and able to provide informed consent.
4. Patients will be undergoing liver graft biopsy (for any reason), or have had a liver biopsy within 48 hours of consent.

Exclusion Criteria:

1. Repeat transplant
2. Recipient of multi organ transplantation
3. Any treatment for graft rejection such as IV steroids has been given before biopsy.
4. Targeted biopsies for diagnosis of malignancy.

Liver transplant patient with graft pathology

Data will be collected from EPIC by UHN study team. Patient information will be de-identified, and each participant will be identified by a unique study number. The study investigators and UHN Ethics Board may access all PHI being collected for this study for audit/inspection purposes.

36 months

At the time of publication, data generated and analyzed as part of this study, including de-identified datasets and gene expression, will be made available in appropriate community-endorsed, public repositories and/or databases. In particular, gene expression data, and the corresponding sex, age, and disease type of each sample will be made available in open-access or controlled-access platforms. This access is subject to restrictions that may be imposed via existing collaboration agreements. No identifiers will leave UHN.