Anil B. Seetharam

Validation of the Prague C & M criteria for the endoscopic grading of Barrett's esophagus by gastroenterology trainees: a multicenter study

BACKGROUND The Prague C & M criteria, developed for the endoscopic grading of Barretts esophagus (BE), (C = circumferential length, M = maximal length) were previously validated among a panel of 29 expert endoscopists with a special interest in BE. Its performance among gastroenterology trainees is unknown. OBJECTIVE To test interobserver agreement among gastroenterology trainees for the Prague C & M criteria, identification of the gastroesophageal junction (GEJ) and the diaphragmatic hiatus. DESIGN A prospective study. SETTING Two tertiary referral centers. PATIENTS AND INTERVENTIONS Standardized endoscopic videos were used. MAIN OUTCOME MEASUREMENTS Interobserver agreement. RESULTS Eighteen high-quality videos (normal esophagus, short and long lengths of BE, equally distributed) were independently evaluated by 18 gastroenterology trainees (year 1, n = 5; year 2, n = 6; year 3, n = 7) after administration of a formal teaching module by an expert endoscopist. Overall intraclass correlation coefficients for assessment of the C and M extent of the endoscopic BE segment above the GEJ were 0.94 (95% CI, 0.89-0.98) and 0.96 (95% CI, 0.94-0.98), respectively. The overall intraclass correlation coefficients for GEJ and diaphragmatic hiatus location recognition were 0.92 (0.86-0.96) and 0.90 (0.82-0.95), respectively. The year of training did not affect interobserver agreement. LIMITATIONS The use of videos for endoscopic evaluation. CONCLUSION After standardized teaching, the Prague C & M criteria have high overall validity among gastroenterology trainees irrespective of the level of training for endoscopic evaluation of visualized BE lengths as well as key endoscopic landmarks.

Characterization of HCV-Specific CD4+Th17 Immunity in Recurrent Hepatitis C–Induced Liver Allograft Fibrosis

Hepatitis C virus (HCV) recurrence with accelerated fibrosis following orthotopic liver transplantation (OLT) is a universal phenomenon. To evaluate mechanisms contributing to HCV induced allograft fibrosis/cirrhosis, we investigated HCV‐specific CD4+Th17 cells and their induction in OLT recipients with recurrence utilizing 51 HCV+ OLT recipients, 15 healthy controls and 9 HCV‐ OLT recipients. Frequency of HCV specific CD4+ Tcells secreting IFN‐γ, IL‐17 and IL‐10 was analyzed by ELISpot. Serum cytokines and chemokines were analyzed by LUMINEX. Recipients with recurrent HCV induced allograft inflammation and fibrosis/cirrhosis demonstrated a significant increase in frequency of HCV specific CD4+Th17 cells. Increased pro‐inflammatory mediators (IL‐17, IL‐1β, IL‐6, IL‐8 and MCP‐1), decreased IFN‐γ, and increased IL‐4, IL‐5 and IL‐10 levels were identified. OLT recipients with allograft inflammation and fibrosis/cirrhosis demonstrated increased frequency of Foxp3+ regulatory T cells (Tregs) that inhibited HCV specific CD4+Th1 but not Th17 cells. This suggests that recurrent HCV infection in OLT recipients induces an inflammatory milieu characterized by increased IL‐6, IL‐1β and decreased IFN‐γ which facilitates induction of HCV specific CD4+Th17 cells. These cells are resistant to suppression by Tregs and may mediate an inflammatory cascade leading to cirrhosis in OLT recipients following HCV recurrence.

Alloimmunity and autoimmunity in chronic rejection

Purpose of reviewRecent studies demonstrate an increasing role for alloimmune responses in the disruption of self-tolerance leading to immune responses to self-antigens that play a role in the immunopathogenesis of chronic rejection following solid organ transplantation. This review summarizes recent studies and implications for the alloimmune-response-induced de-novo development of autoimmune responses following solid organ transplantations. Recent findingsImmediately following organ transplantation, several factors lead to enduring an inflammatory milieu. Studies from our laboratory and others have demonstrated that development of antihuman leukocyte antigen antibodies precedes the development of chronic rejection. Using an in-vivo murine model, we have demonstrated that administration of anti-major histocompatibility complex (MHC) class I directly into the native lungs leads to chronic rejection pathology. Further, the in-vitro ligation of epithelial cell surface MHC class I molecules by specific anti-MHC can lead to cell activation and production of fibrinogenic growth factors. SummaryOn the basis of these findings, we hypothesized that alloimmune responses can lead to autoimmunity, thus playing an important role in chronic rejection. Characterization of both the temporal occurrence and functional significance of antibodies to self-antigens may provide insight into the pathogenesis of chronic rejection and these antibodies can serve as clinically useful biomarkers.

Immunosuppression in Patients with Chronic Hepatitis B

After hepatitis B virus (HBV) infection, HBV DNA persists in minute amounts in hepatocyte nuclei even in individuals with “resolved” infection. Viral replication and development of liver disease depend on the balance between viral mechanisms promoting persistence and host immune control. Patients with active or inactive disease or resolved HBV infection are at risk for reactivation with immunosuppressive therapy use. HBV reactivation varies from a clinically asymptomatic condition to one associated with acute liver failure and death. We review recent studies on HBV reactivation during immunomodulatory therapies for oncologic, gastroenterological, rheumatic, and dermatologic disorders. Risk calculation should be determined through HBV screening and assessment of immunosuppressive therapy potency. We also discuss monitoring for reactivation, prophylactic antiviral therapy, and treatment of reactivation. Prophylactic antiviral treatment is needed for all HBsAg carriers and selected patients who have anti-HBc without HBsAg and is critical for preventing viral reactivation and improving outcomes.

Donor graft steatosis influences immunity to hepatitis C virus and allograft outcome after liver transplantation.

Background. Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) is universal, often with accelerated allograft fibrosis. Donor liver steatosis is frequently encountered and often associated with poor early postoperative outcome. The aim of this study was to test the hypothesis that allograft steatosis alters immune responses to HCV and self-antigens promoting allograft fibrosis. Methods. Forty-eight HCV OLT recipients (OLTr) were enrolled and classified based on amount of allograft macrovesicular steatosis at time of OLT. Group 1: no steatosis (0%–5% steatosis, n=21), group 2: mild (5%–35%, n=16), and group 3: moderate (>35%, n=11). Cells secreting interleukin (IL)-17, IL-10, and interferon gamma (IFN-&ggr;) in response to HCV antigens were enumerated by Enzyme Linked Immunospot Assay. Serum cytokines were measured by Luminex, antibodies to Collagen I, II, III, IV, and V by ELISA. Results. OLTr of moderate steatotic grafts had the highest incidence of advanced fibrosis in protocol 1 year post-OLT biopsy (10.8% vs. 15.8% vs. 36.6%, r=0.157, P<0.05). OLTr from groups 2 and 3 had increased HCV-specific IL-17 (P<0.05) and IL-10 (P<0.05) with reduced IFN-&ggr; (P<0.05) secreting cells when compared with group 1. This was associated with increase in serum IL-17, IL-10, IL-1&bgr;, IL-6, IL-5, and decreased IFN-&ggr;. In addition, there was development of antibodies to Collagen I, II, III and V in OLTr with increased steatosis (P<0.05). Conclusion. The results demonstrate that allograft steatosis influences post-OLT HCV-specific immune responses leading to an IL-17 T-helper response and activation of humoral immune responses to liver-associated self-antigens that may contribute to allograft fibrosis and poor outcome.

Infections after orthotopic liver transplantation.

Opportunistic infections are a leading cause of morbidity and mortality after orthotopic liver transplantation. Systemic immunosuppression renders the liver recipient susceptible to de novo infection with bacteria, viruses and fungi post-transplantation as well to reactivation of pre-existing, latent disease. Pathogens are also transmissible via the donor organ. The time from transplantation and degree of immunosuppression may guide the differential diagnosis of potential infectious agents. However, typical systemic signs and symptoms of infection are often absent or blunted after transplant and a high index of suspicion is needed. Invasive procedures are often required to procure tissue for culture and guide antimicrobial therapy. Antimicrobial prophylaxis reduces the incidence of opportunistic infections and is routinely employed in the care of patients after liver transplant. In this review, we survey common bacterial, fungal, and viral infections after orthotopic liver transplantation and highlight recent developments in their diagnosis and management.

Immune response to extracellular matrix collagen in chronic hepatitis C–induced liver fibrosis

Hepatitis C virus (HCV) infection and its recurrence after orthotopic liver transplantation (OLT) are associated with the remodeling of extracellular matrix (ECM) components [particularly collagen (Col)], which leads to fibrosis. Our aim was to determine whether the development of antibodies (Abs) to self‐antigen Col in HCV‐infected patients correlates with the fibrosis stage and the peripheral cytokine response. Patients with chronic HCV infection, patients with HCV recurrence after OLT who had undergone a biopsy procedure, and healthy control subjects were enrolled. The HCV subjects (n = 70) were stratified as follows: (1) a non‐OLT group without fibrosis (Scheuer stages 0‐2), (2) a non‐OLT group with fibrosis (Scheuer stages 3‐4), (3) a post‐OLT group without fibrosis (Scheuer stages 0‐2), and (4) a post‐OLT group with fibrosis (Scheuer stages 3‐4). Serum samples were analyzed for Abs against Col1, Col2, Col4, Col5, and vimentin with enzyme‐linked immunosorbent assays. Serum levels of cytokines were measured with multiplex bead immunoassays. The levels of Abs to Col1 were higher in the fibrosis groups versus the no‐fibrosis groups and the controls for both non‐OLT patients (P < 0.001) and post‐OLT patients (P = 0.01). There were increased levels of Abs to Col2, Col4, Col5, and vimentin in the non‐OLT fibrosis group (Col2, P = 0.0001; Col4, P = 0.122; Col5, P < 0.0001; vimentin, P = 0.36) and in the post‐OLT fibrosis group (Col2, P = 0.006; Col4, P = 0.19; Col5, P < 0.0001; vimentin, P = 0.24) in comparison with the no‐fibrosis groups. The non‐OLT and post‐OLT fibrosis groups demonstrated significantly higher T helper 2 (Th2) and T helper 17 (Th17) cytokine levels and lower T helper 1 cytokine levels in comparison with the no‐fibrosis groups. Our results demonstrate that in HCV‐infected patients, the levels of Abs to ECM Col1, Col2, and Col5 positively correlate with liver fibrosis, which is associated with a predominantly Th2 and Th17 cytokine profile. Liver Transpl 17:814‐823, 2011.

Temporal association between increased virus-specific Th17 response and spontaneous recovery from recurrent hepatitis C in a liver transplant recipient.

Background. Spontaneous clearance of hepatitis C virus (HCV) after orthotopic liver transplantation (OLT) is a rare occurrence. Here, we present detailed immunological analysis of an interferon naive OLT recipient receiving uninterrupted immunosuppression who cleared HCV spontaneously 2 years after transplantation. Methods. Enzyme-linked immunospot assay analysis of peripheral T-cell interferon gamma (IFN-&ggr;), interleukin (IL)-10, and IL-17 response to HCV core and nonstructural antigen 4 and enzyme-linked immunosorbent assay (ELISA) to collagen (Col) subtypes I, II, IV, and V were performed in the index patient at the time of viral clearance and compared with an OLT cohort with persistent viremia matched for time from OLT, immunosuppression, and histology. Enzyme-linked immunospot assay and ELISA analysis were repeated on the patient 4 years after OLT. Transcription-mediated amplification assays were used to confirm viral clearance. Results. Compared with a cohort of post-OLT and nontransplanted viremic HCV patients, the index patient with HCV clearance demonstrated higher IL-17, IL-10, and lower IFN-&ggr; response to nonstructural antigen 4 and core antigen and a higher titer of antibodies (Abs) to Col subtypes I, II, and V during clearance. On follow-up 2 years later, HCV-specific IFN-&ggr; was increased in the index patient, with a decline in IL-17 and IL-10 response and Col I, II, and V Ab titer. Conclusions. Virus-induced activation of Th-17 cells may contribute to HCV clearance post-OLT. Maintenance of viral suppression may be facilitated by restoration of Th1 (IFN-&ggr;) responses. Modulation of Th17 immunity deserves further attention as a therapeutic strategy in the treatment of HCV recurrence post-OLT.

Primary Biliary Cholangitis: Disease Pathogenesis and Implications for Established and Novel Therapeutics

Primary Biliary Cholangitis is a progressive, autoimmune cholestatic liver disorder. Cholestasis with disease progression may lead to dyslipidemia, osteodystrophy and fat-soluble vitamin deficiency. Portal hypertension may develop prior to advanced stages of fibrosis. Untreated disease may lead to cirrhosis, hepatocellular cancer and need for orthotopic liver transplantation. Classically, diagnosis is made with elevation of alkaline phosphatase, demonstration of circulating antimitochondrial antibody, and if performed: asymmetric destruction/nonsupperative cholangitis of intralobular bile ducts on biopsy. Disease pathogenesis is complex and results from innate and adaptive (cell-mediated and humoral) responses that lead to inflammation of biliary duct epithelium. Ongoing damage is amplified and sustained through bile acid toxicity. Use of weight based (13-15mg/kg) ursodeoxycholic acid is well established in retarding disease progression and improving survival; however, is ineffective in achieving complete biochemical remission in many. Recently, a Farnesoid X Receptor agonist, obeticholic acid, has been approved for use. A number of ongoing clinical studies are underway to evaluate utility of fibric acid derivatives, biologics, antifibrotics, and stem cells as monotherapy or in combination with ursodeoxycholic acid for primary biliary cholangitis. The aim of this review is to discuss disease pathogenesis and highlight rationale/implications for both established and novel therapeutics.

Pretransplant Factors and Associations with Postoperative Respiratory Failure, ICU Length of Stay, and Short-Term Survival after Liver Transplantation in a High MELD Population

Changes in distribution policies have increased median MELD at transplant with recipients requiring increasing intensive care perioperatively. We aimed to evaluate association of preoperative variables with postoperative respiratory failure (PRF)/increased intensive care unit length of stay (ICU LOS)/short-term survival in a high MELD cohort undergoing liver transplant (LT). Retrospective analysis identified cases of PRF and increased ICU LOS with recipient, donor, and surgical variables examined. Variables were entered into regression with end points of PRF and ICU LOS > 3 days. 164 recipients were examined: 41 (25.0%) experienced PRF and 74 (45.1%) prolonged ICU LOS. Significant predictors of PRF with univariate analysis: BMI > 30, pretransplant MELD, preoperative respiratory failure, LVEF < 50%, FVC < 80%, intraoperative transfusion > 6 units, warm ischemic time > 4 minutes, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted PRF (OR 1.14, p = 0.01). Significant predictors of prolonged ICU LOS with univariate analysis are as follows: pretransplant MELD, FVC < 80%, FEV1 < 80%, deceased donor, and cold ischemic time > 240 minutes. On multivariate analysis, only pretransplant MELD predicted prolonged ICU LOS (OR 1.28, p < 0.001). One-year survival among cohorts with PRF and increased ICU LOS was similar to subjects without. Pretransplant MELD is a robust predictor of PRF and ICU LOS. Higher MELDs at LT are expected to increase need for ICU utilization and modify expectations for recovery in the immediate postoperative period.