Polymerase chain reaction and in situ hybridization of Epstein-Barr virus in liver biopsy specimens facilitate the diagnosis of EBV hepatitis after liver transplantation

Liver biopsy in children: position paper of the ESPGHAN Hepatology Committee

Liver biopsy (LB) is still the criterion standard procedure for obtaining liver tissue for histopathological examination and a valuable tool in the diagnosis, prognosis, and management of many parenchymal liver diseases. The aim of this position paper is to summarise the present practice of paediatric LB and make recommendations about its performance. Although histological evaluation of the liver is important in assessing prognosis and exploring treatment, noninvasive techniques (ie, imaging, laboratory markers) may replace use of liver histology. The indications for LB are changing as present knowledge of aetiologies, pathomechanism, and therapeutic options in paediatric liver disease is evolving. Adult and paediatric literature was reviewed to assess the existing clinical practice of LB with focus on the technique, indications, risk of complications, and contraindications in paediatrics. This position paper presents types of LB, indications, complications, contraindications, and an essential checklist for paediatric LB.

Liver Transplant Pathology: Review of Challenging Diagnostic Situations

Histopathologic assessment of allograft liver biopsies has an important role in managing patients who have undergone liver transplantation. In this review, several topics are discussed that create diagnostic problems in transplant pathology, with emphasis on pathologic features and differential diagnosis. The topics discussed are acute cellular rejection, late acute rejection (centrizonal/parenchymal rejection), chronic rejection, plasma cell hepatitis, idiopathic posttransplant chronic hepatitis, fibrosing cholestatic hepatitis, selected viral infections (cytomegalovirus, Epstein-Barr virus, and hepatitis E), and acute antibody-mediated rejection.

High intrahepatic HHV-6 virus loads but neither CMV nor EBV are associated with decreased graft survival after diagnosis of graft hepatitis

BACKGROUND & AIMS

In liver transplant recipients with graft hepatitis, the relevance of herpesviruses is not well defined.

METHODS

Viral loads of CMV, EBV, and HHV-6 were determined in blood and liver biopsies of 170 liver transplant recipients with graft hepatitis by quantitative PCR.

RESULTS

HHV-6-, CMV-, and EBV-DNA were detected in 58%, 14%, and 44% of the biopsies, respectively, with coinfections in 34%. High intrahepatic HHV-6 DNA levels (>75th percentile, 11.27 copies/1000 cells) and detection of HHV-6 DNAemia were significantly associated with decreased graft survival after diagnosis of graft hepatitis (p=0.014 and p=0.003, respectively, median follow-up was 23.8 months). Multivariate analysis confirmed high intrahepatic HHV-6 loads as an independent factor associated with reduced graft survival (adjusted hazard ratio 2.61, 95%confidence interval 1.16-5.87). Low concentrations of HHV6 DNA in the liver, indicating latent infection, did not influence graft survival. Neither CMV nor EBV (qualitative detection and high virus loads) nor acute rejection (according to the BANFF score) affected graft survival. However, patients had been treated for CMV reactivations and acute rejections in this retrospective study. High age and high bilirubin levels were the other independent factors associated with reduced graft survival (adjusted hazard ratio 3.56CI 1.52-8.34 and 3.23CI 1.50-6.96, respectively).

CONCLUSIONS

High intrahepatic HHV-6-DNA levels are associated with decreased graft survival in liver transplant recipients with graft hepatitis. The significance of HHV-6 as potential etiology of graft hepatitis needs further evaluation.

Infectious diseases and the liver

The liver plays an important role in host defense against invasive microorganisms. The effect of microbial pathogens on the liver can vary greatly, presenting with a wide variety of manifestations from asymptomatic increases in aminotransaminases, acute liver failure, hepatic fibrosis, and cirrhosis. In evaluating the liver manifestations of a potential infectious pathogen, diagnosis of some of the less common infectious pathogens is dependent on a high level of suspicion and recognition of some of the key diagnostic clues. Successful diagnosis can only be accomplished through a careful history, including travel and exposures, physical examination, and appropriate microbiologic studies. This article reviews the involvement of the liver during systemic infections with organisms that are not considered to be primarily hepatotropic.

Epstein-Barr virus hepatitis: diagnostic value of in situ hybridization, polymerase chain reaction, and immunohistochemistry on liver biopsy from immunocompetent patients

Epstein-Barr virus (EBV) hepatitis is an uncommon, almost always self-limited disease in immunocompetent patients. Accurate diagnosis is imperative for appropriate clinical management. The aim of this study was to compare 3 available methods for EBV detection on routinely processed liver biopsies to determine their effectiveness in aiding the diagnosis. In 6 of the 8 cases of EBV hepatitis, EBV was detected by both polymerase chain reaction (PCR) for EBV DNA and in situ hybridization (ISH) for EBV early RNA (EBER). EBV was detected by PCR only in 1 case, and by ISH only in another. EBER-positive cells detected by ISH were typically few and individually distributed in the portal tracts and sinusoids. Immunohistochemical staining for EBV latent membrane proteins was negative in all 8 cases. Five cases of chronic hepatitis C used as negative controls were negative by all 3 detection methods for EBV. These data indicate that PCR and ISH are equally sensitive in detecting EBV in routinely processed liver biopsies. The ready implementation of ISH in pathology laboratories makes it a useful ancillary tool in confirming the diagnosis of EBV hepatitis in equivocal cases. However, EBER-positive cells can be sparse and easily overlooked. Immunohistochemistry for EBV latent membrane proteins apparently has no utility in the diagnosis of EBV hepatitis.

Tissue HHV6 and 7 determination in pediatric solid organ recipients--a pilot study

Herpes virus infections remain a major challenge in solid organ transplantation. HHV6 and 7 blood viral load was associated with pathology after renal transplantation. Little is known about the significance of tissue HHV6 and 7 infections. A total of 18 tissue biopsies (13 kidney, three GI and two BAL) from nine pediatric transplant patients (five kidney, two liver, one combined liver and kidney and one bone marrow transplant) were subjected to blood HHV6 IgG and IgM testing. In addition, tissue HHV6 and 7 semi-quantitative PCR analysis with subsequent detection by ELISA and quantitative methods were applied to the same samples. We also studied four native kidney biopsies of children with other kidney disease. The results of the biopsies were correlated with clinical data. Of the transplant patients, 78% were HHV6 IgG positive. Six of nine had a positive IgM on at least one occasion, however, only two of nine transplant patients were symptomatic with a mixed CMV/EBV septic picture of multi-organ failure. Only these two patients had a significant tissue viral load for HHV6. Additionally, a very significant tissue viral load for HHV6 was detected in an immunocompromised patient 3 wk after a roseola-like febrile illness. The HHV6 copies were 31, 88 and 206 per 10 microL of DNA, respectively. In the patient who also had the fourth positive ELISA for HHV6 PCR product, the Multiplex PCR and restriction enzyme assay on its PCR product revealed a significant contribution by HHV7, while the HHV6-B signal was rather weak. Significant tissue HHV6 loads can be found in tissue biopsies from organ recipients with significant illness and also in native kidneys after primary infection. This may explain the high prevalence of HHV6 in transplanted kidneys. Further studies on HHV6 and 7 using molecular techniques should be supported.

Epstein-Barr virus latency in kidney specimens from transplant recipients

BACKGROUND

Epstein-Barr virus (EBV) infection is common in immunosuppressed patients and can lead to life threatening lymphoproliferative diseases. Small numbers of cells infected by EBV have been detected in human tissues, transplanted or non-transplanted. Little is known about EBV latency in the allograft kidneys of patients without post-transplant lymphoproliferative disease (PTLD). The aims of this study were to look for the presence of EBV-encoded small RNAs (EBER) in allograft kidneys and to quantify their expression.

METHODS

We analysed 62 allograft nephrectomies and 20 native kidneys to determine the presence of EBV; we also quantified its expression and calculated its ratios to CD45 and CD20 cells. The techniques used were: tissue microarray, EBER-1- and 2-specific in situ hybridization and immunohistochemistry.

RESULTS

EBER expression was detected in 30.6% of transplanted kidneys and 5% of non-transplanted kidneys. In the positive specimens, a mean of 8.2 cells/1.57 mm(2) expressed the EBERs (range 1-38 cells). The ratios of EBER-positive (+) cells to CD45 or CD20 cells were 1.7 +/- 2.4% (range 0.1-8.1%) and 8.4 +/- 10.9% (range 0.5-34.4%), respectively. No relationship was found between anti-T-cell treatment and EBER expression in the failed allografts.

CONCLUSIONS

In failed kidney allografts, a small number of lymphocytes can express EBV latency. The number of EBER+ cells is smaller than in PTLD. Studies of functioning grafts are necessary to better understand the clinical relevance of this expression.

Quantitative tissue polymerase chain reaction for Epstein-Barr virus in pediatric solid organ recipients

BACKGROUND

Infections caused by herpes virus, in particular, Epstein-Barr virus (EBV), remain a major challenge in solid organ transplantation. Little is known about the significance of tissue EBV load.

METHODS

Twenty-three tissue biopsy specimens (19 kidney, 3 gastrointestinal, and 1 tonsil specimen) and 2 bronchoalveolar lavage specimens from 14 pediatric transplant recipients (10 kidney, 3 liver, 1 combined transplant) were subject to tissue EBV polymerase chain reaction (PCR) semiquantitative analysis and enzyme-linked immunosorbent assay (ELISA) methods. Results of biopsies were correlated with clinical data.

RESULTS

Five of 14 patients had clinically diagnosed EBV disease: 2 patients presented with a septic picture with multiorgan failure and pneumonitis; 1 patient had mononucleosis; 1 patient had an increase in serum creatinine level, lymphadenopathy, and chronic fatigue; and 1 patient had EBV nephritis. These 5 patients underwent 12 biopsies at the time of clinically active infection; 8 biopsies had positive results (up to 111 copies/10 microL of extracted DNA). Conversely, 1 of the remaining 13 tissue biopsy specimens from asymptomatic patients had positive results on ELISA, but undetectable viral load, whereas 8 patients had a positive EBV immunoglobulin G titer with historic evidence of EBV replication in the blood. No patient without evidence of EBV had positive EBV tissue PCR results.

CONCLUSION

Increased EBV load was found in more than 50% of patients, pointing to a previously underrecognized importance of EBV detection in tissues from transplant recipients. The presence of EBV in tissue correlated with the presence of viremia, whereas tissue PCR had 100% specificity. EBV load should be included in biopsy evaluation.

Allograft liver biopsy in patients with Epstein-Barr virus-associated posttransplant lymphoproliferative disease

Allograft liver biopsy specimens (n = 24) obtained in the clinical setting of primarily extrahepatic posttransplant lymphoproliferative disease (PTLD) were studied for histopathology, lymphocyte subsets, and Epstein-Barr virus (EBV)-encoded EBER RNA. Acute rejection was found in 20 (83.3%) of 24 biopsy specimens and graded as indeterminate in 7 (35%) of 20 (35%), mild in 3 (15%) of 20, and moderate in 10 (50%) of 20 cases. EBV hepatitis was the primary diagnosis in two biopsy specimens and a secondary finding in six others. Four biopsy specimens showed nonspecific reactive hepatitis, and five showed recurrence of primary liver disease. Immunoperoxidase staining showed primarily T cells. EBER RNA was detected in 14 (58.3%) of 24 biopsy specimens: 12 (60%) of 20 with and 2 (50%) of 4 without acute rejection. Antirejection therapy resulted in complete or partial response in 4 (36.3%) of 11 and 7 (63.7%) of 11 treated cases, respectively, despite the presence of EBV-infected cells in some tissues. Subsequent follow-up showed early or late chronic rejection in 6 (25%) of 24 patients. Gamma glutamyl transferase, a marker for early or late chronic rejection, was greater than five times the upper limit of normal in 9 (37.5%) of 24 patients. In conclusion, liver biopsy specimens in patients with PTLD show a spectrum of pathologic changes. Rejection may be treated even if EBV is concurrently present. Long-term graft is suboptimal, because low immunosuppression results in a tendency to develop chronic rejection.