New Approaches to the Diagnosis of Rejection and Prediction of Tolerance in Liver Transplantation

Immunosuppression after liver transplantation is essential for preventing allograft rejection. However, long-term drug toxicity and associated complications necessitate investigation of immunosuppression minimization and withdrawal protocols. Development of such protocols is hindered by reliance on current paradigms for monitoring allograft function and rejection status. The current standard of care for diagnosis of rejection is histopathologic assessment and grading of liver biopsies in accordance with the Banff Rejection Activity Index. However, this method is limited by cost, sampling variability, and interobserver variation. Moreover, the invasive nature of biopsy increases the risk of patient complications. Incorporating noninvasive techniques may supplement existing methods through improved understanding of rejection causes, hepatic spatial architecture, and the role of idiopathic fibroinflammatory regions. These techniques may also aid in quantification and help integrate emerging -omics analyses with current assessments. Alternatively, emerging noninvasive methods show potential to detect and distinguish between different types of rejection while minimizing risk of adverse advents. Although biomarkers have yet to replace biopsy, preliminary studies suggest that several classes of analytes may be used to detect rejection with greater sensitivity and in earlier stages than traditional methods, possibly when coupled with artificial intelligence. Here, we provide an overview of the latest efforts in optimizing the diagnosis of rejection in liver transplantation.

Incidence and distribution of UroSEEK gene panel in a multi-institutional cohort of bladder urothelial carcinoma

Noninvasive approaches for early detection of bladder cancer are actively being investigated. We recently developed a urine- based molecular assay for the detection and surveillance of bladder neoplasms (UroSEEK). UroSEEK is designed to detect alterations in 11 genes that include most common genetic alterations in bladder cancer. In this study, we analyzed 527 cases, including 373 noninvasive and 154 invasive urothelial carcinomas of bladder from transurethral resections or cystectomies performed at four institutions (1991-2016). Two different mutational analysis assays of a representative tumor area were performed: first, a singleplex PCR assay for evaluation of the TERT promoter region (TERTSeqS) and second, a multiplex PCR assay using primers designed to amplify regions of interest of 10 (FGFR3, PIK3CA, TP53, HRAS, KRAS, ERBB2, CDKN2A, MET, MLL, and VHL) genes (UroSeqS). Overall, 92% of all bladder tumors were positive for at least one genetic alteration in the UroSEEK panel. We found TERT promoter mutations in 77% of low-grade noninvasive papillary carcinomas, with a relatively lower incidence of 65% in high-grade noninvasive papillary carcinomas and carcinomas in situ; p = 0.017. Seventy-two percent of pT1 and 63% of muscle-invasive bladder tumors harbored TERT promoter mutations with g.1295228C>T alteration being the most common in all groups. FGFR3 and PIK3CA mutations were more frequent in low-grade noninvasive papillary carcinomas compared with high-grade noninvasive papillary carcinomas and carcinomas in situ (p < 0.0001), while the opposite was true for TP53 (p < 0.0001). Significantly higher rates of TP53 and CDKN2A mutation rates (p = 0.005 and 0.035, respectively) were encountered in muscle-invasive bladder tumors compared with those of pT1 stage. The overwhelming majority of all investigated tumors showed at least one mutation among UroSEEK assay genes, confirming the comprehensive coverage of the panel and supporting its potential utility as a noninvasive urine-based assay.

Circulating microparticles as disease-specific biomarkers of severity of inflammation in patients with hepatitis C or nonalcoholic steatohepatitis

BACKGROUND & AIMS

Microparticles released into the bloodstream upon activation or apoptosis of CD4(+) and CD8(+) T cells correlate with inflammation as determined by histologic analysis in patients with chronic hepatitis C (CHC). Patients with nonalcoholic fatty liver (NAFL) or nonalcoholic steatohepatitis (NASH) can be differentiated from those with CHC based on activation of distinct sets of immune cells in the liver.

METHODS

We compared profiles of circulating microparticles from patients with NAFL and NASH (n = 67) to those of CHC (n = 42), with healthy individuals (controls) using flow cytometry; the profiles were correlated with inflammation grade and fibrosis stage based on histologic analyses. We assessed the ability of the profiles to determine the severity of inflammation and fibrosis based on serologic and histologic analyses.

RESULTS

Patients with CHC had increased levels of microparticles from CD4(+) and CD8(+) T cells; the levels correlated with disease severity based on histologic analysis and levels of alanine aminotransferase. Patients with NAFL or NASH had significant increases in numbers of microparticles from invariant natural killer T cells and macrophages/monocytes (CD14(+)), which mediate pathogenesis of NASH. Microparticles from CD14(+) and invariant natural killer T cells correlated with levels of alanine aminotransferase and severity of NASH (based on histology). Levels of microparticles could differentiate between patients with NAFL or NASH and those with CHC, or either group of patients and controls (area under the receiver operating characteristic curves ranging from 0.56 to 0.99).

CONCLUSIONS

Quantification of immune cell microparticles from serum samples can be used to assess the extent and characteristics of hepatic inflammation in patients with chronic liver disease.