Acute hepatitis A infection in hepatitis B chimpanzee carriers

Natural pathology of the captive chimpanzee (Pan troglodytes): A 35-year review

We present the spontaneous pathological lesions identified as a result of necropsy or biopsy for 245 chimpanzees (Pan troglodytes) over a 35-year period. A review of the pathology database was performed for all diagnoses on chimpanzees from 1980 to 2014. All morphologic diagnoses, associated system, organ, etiology, and demographic information were reviewed and analyzed. Cardiomyopathy was the most frequent lesion observed followed by hemosiderosis, hyperplasia, nematodiasis, edema, and hemorrhage. The most frequently affected systems were the gastrointestinal, cardiovascular, urogenital, respiratory, and lymphatic/hematopoietic systems. The most common etiology was undetermined, followed by degenerative, physiologic, neoplastic, parasitic, and bacterial. Perinatal and infant animals were mostly affected by physiologic etiologies and chimpanzee-induced trauma. Bacterial and physiologic etiologies were more common in juvenile animals. Degenerative and physiologic (and neoplastic in geriatric animals) etiologies predominated in adult, middle aged, and geriatric chimpanzees.

Natural mortality and cause of death analysis of the captive chimpanzee (Pan troglodytes): A 35-year review

We present the spontaneous causes of mortality for 137 chimpanzees (Pan troglodytes) over a 35-year period. A record review of the pathology database was performed and a primary cause of mortality was determined for each chimpanzee. The most common causes of mortality were as follows: cardiomyopathy (40% of all mortalities), stillbirth/abortion, acute myocardial necrosis, chimpanzee-induced trauma, amyloidosis, and pneumonia. Five morphologic diagnoses accounted for 61% of mortalities: cardiomyopathy, hemorrhage, acute myocardial necrosis, amyloidosis, and pneumonia. The most common etiologies were degenerative, undetermined, bacterial, traumatic, and neoplastic. The cardiovascular system was most frequently involved, followed by the gastrointestinal, respiratory, and multisystemic diseases. Degenerative diseases were the primary etiological cause of mortality of the adult captive chimpanzee population. Chimpanzee-induced trauma was the major etiological cause of mortality among the perinatal and infant population. This information should be a useful resource for veterinarians and researchers working with chimpanzees.

Suppression of hepatitis B virus replication mediated by hepatitis A-induced cytokine production

BACKGROUND

Acute hepatitis A virus (HAV) infection can cause severe hepatitis especially in patients with underlying chronic liver disease. In patients with pre-existing chronic hepatitis B (HBV) acute HAV infection can suppress HBV replication. The exact mechanism of HBV suppression during acute HAV infection is still a subject of debate. One mechanism may be the production of HAV infection-induced cytokines leading to suppression of HBV replication and viral clearance.

AIM

To evaluate cytokine production and HBV-specific lympho-proliferative responses (LPR) during acute HAV infection in a patient with chronic HBV infection-clearing markers of active HBV replication.

DESIGN

Early detection of a case of acute HAV infection in an HBeAg-positive, HBV DNA-positive chronic HBV patient treated with lamivudine.

RESULTS

At the time of HAV infection a sharp peak in the gamma-interferon (IFN-gamma) level occurred just before the rise in serum transaminase activity. This was subsequently followed by a decrease in HBV DNA and HBeAg below the limit of detection of the assay. However the HBV-specific T-cell response was not modified. After resolution of the acute HAV infection and withdrawal of antiviral therapy HBV replication relapsed.

CONCLUSION

The sharp rise in IFN-gamma production mediated by the acute HAV infection may be pivotal in the suppression of HBV replication in chronic hepatitis B.

Combination therapy with lamivudine and adenovirus causes transient suppression of chronic woodchuck hepatitis virus infections

Treatment of hepatitis B virus carriers with the nucleoside analog lamivudine suppresses virus replication. However, rather than completely eliminating the virus, long-term treatment often ends in the outgrowth of drug-resistant variants. Using woodchucks chronically infected with woodchuck hepatitis virus (WHV), we investigated the consequences of combining lamivudine treatment with immunotherapy mediated by an adenovirus superinfection. Eight infected woodchucks were treated with lamivudine and four were infected with approximately 10(13) particles of an adenovirus type 5 vector expressing beta-galactosidase. Serum samples and liver biopsies collected following the combination therapy revealed a 10- to 20-fold reduction in DNA replication intermediates in three of four woodchucks at 2 weeks after adenovirus infection. At the same time, covalently closed circular DNA (cccDNA) and viral mRNA levels both declined about two- to threefold in those woodchucks, while mRNA levels for gamma interferon and tumor necrosis factor alpha as well as for the T-cell markers CD4 and CD8 were elevated about twofold. Recovery from adenovirus infection was marked by elevation of sorbitol dehydrogenase, a marker for hepatocyte necrosis, as well as an 8- to 10-fold increase in expression of proliferating cell nuclear antigen, a marker for DNA synthesis, indicating significant hepatocyte turnover. The fact that replicative DNA levels declined more than cccDNA and mRNA levels following adenovirus infection suggests that the former decline either was cytokine induced or reflects instability of replicative DNA in regenerating hepatocytes. Virus titers in all four woodchucks were only transiently suppressed, suggesting that the effect of combination therapy is transient and, at least under the conditions used, does not cure chronic WHV infections.

Hepatitis B virus biology

Hepadnaviruses (hepatitis B viruses) cause transient and chronic infections of the liver. Transient infections run a course of several months, and chronic infections are often lifelong. Chronic infections can lead to liver failure with cirrhosis and hepatocellular carcinoma. The replication strategy of these viruses has been described in great detail, but virus-host interactions leading to acute and chronic disease are still poorly understood. Studies on how the virus evades the immune response to cause prolonged transient infections with high-titer viremia and lifelong infections with an ongoing inflammation of the liver are still at an early stage, and the role of the virus in liver cancer is still elusive. The state of knowledge in this very active field is therefore reviewed with an emphasis on past accomplishments as well as goals for the future.

Exclusion in liver by polymerase chain reaction of hepatitis B and C viruses in acute liver failure attributed to sporadic non-A, non-B hepatitis

Hepatitis B and C viruses have been implicated in a few cases of acute liver failure attributed to sporadic (community acquired) non-A, non-B hepatitis, but reports are conflicting. We determined whether hepatitis B virus and hepatitis C virus were detectable in prospectively stored hepatectomies from seven British patients grafted for acute liver failure attributed to sporadic non-A, non-B hepatitis. For hepatitis B virus, we used nested polymerase chain reaction with primers to the core and surface regions. For hepatitis C virus, we used one round of reverse transcription polymerase chain reaction with primers to the 5' untranslated region and Southern hybridization using an internal oligonucleotide probe as well as nested PCR for the E1 region. Positive controls were native livers from two patients with unequivocal fulminant hepatitis B and from four patients with cirrhosis attributed to hepatitis C virus. Our negative findings suggest that, in the UK, acute liver failure attributed to sporadic non-A, non-B hepatitis most likely is caused by agent/s other than hepatitis B and C viruses.

Dissociation of alanine aminotransferase values in acute hepatitis A patients with and without past experience to the hepatitis B virus

Serological markers and peak serum alanine aminotransferase (ALT) values of 140 in-patients with acute hepatitis, either type A (n = 90), or type B (n = 50) were prospectively assessed. In 23 out of the 90 patients with acute hepatitis A, evidence of previous experience with hepatitis B virus (HBV) was found, whereas 35 out of the 50 patients with acute hepatitis B had past contact with hepatitis A virus (HAV). The mean peak ALT values [S.D.] were significantly higher in hepatitis A patients with previous experience with HBV (1413 [704] i.u./l), when compared to those without such experience (842 [464] i.u./l, P less than 0.001). Such a difference was not evident between acute hepatitis B patients, whether or not they had previous contact with HAV. We conclude that when acute hepatitis A is superimposed on past HBV infection an augmented transaminaemia, indicative of enhanced liver cell necrosis, takes place although a definite explanation is lacking. We suggest that individuals with markers of HBV infection should be early candidates for HAV immunization.

Acute hepatic injury after the withdrawal of immunosuppressive chemotherapy in patients with hepatitis B

Five patients with lymphoproliferative malignancies and chronic hepatitis B suffered severe acute hepatic injury after the withdrawal of multiagent chemotherapy that included high-dose corticosteroid. Four patients died of hepatic failure, three of whom received corticosteroid as treatment for the hepatic injury. We believe that the cause of this entity is massive immune-associated cytolysis of hepatitis B virus infected hepatocytes occurring after a period of immunosuppression and increased viral replication. The literature regarding this complication of chemotherapy and its pathophysiology is reviewed.

The significance of infections with two types of viral hepatitis demonstrated by histologic features in chimpanzees

In view of the recognized importance of necroinflammatory episodes in chronic hepatitis B virus (HBV) infection, chimpanzees, either HBV surface antigen (HBsAg) carriers or noninfected (naive), were infected with other primary hepatotropic viruses to evaluate histologic alterations and changes in virologic and biochemical markers of infection. The advantages of studies on chimpanzees are the availability of serial biopsy specimens and the viral type-specific histologic lesions, not as well recognized in humans. Infection with hepatitis A and non-A, non-B (NANB) agents produced more severe lesions in chronic HBsAg carrier chimpanzees than in naive animals. During this superinfection, the specific expression of the second agent was predominant, indicating that the exacerbation is caused by the second agent, but that carriers are prone to more severe disease than the naive chimpanzees. Hepatitis delta virus (HDV) infections were always coexistant with HBV and superinfection of carriers produced histologic changes more severe than those seen in any other type of viral hepatitis. Such HDV infections revealed less evidence of lymphocytotoxicity but rather of cytotoxicity, and sometimes resembled in appearance the histopathology of NANB. Coinfection of HDV and HBV and superinfection of HBV-carriers with NANB resulted in hepatitis that was far less severe than superinfection of HDV in HBV carriers, greatly in keeping with human experiences. HBV replication was suppressed transiently in both NANB and HDV superinfection. This implies that in exacerbations during chronic HBV infections of humans, suppression of HBV replication markers indicates superinfection, for instance, by NANB for which markers are so far not widely available; by contrast, elevated markers of HBV replication suggest reactivation of the original HBV infection.

Hepatitis B virus DNA in the hepatocyte. A series of 160 biopsies

DNA-DNA hybridisation was used to examine 160 liver biopsies for the presence of the hepatitis B virus genome. HBeAg-positive HBsAg carriers were found to have replicating viral DNA in the hepatocytes and, very occasionally, HBV DNA was also integrated into the chromosomes. A high proportion of the anti-HBe-positive HBsAg carriers also have replicating HBV DNA and in the remainder integrated sequences are often, but not always, seen. No evidence was found, however, to implicate HBV in HBsAg-negative patients with alcoholic liver disease, nor in patients with a variety of other liver diseases including non-A, non-B hepatitis.

Liver disease activity and hepatitis B virus replication in chronic delta antigen-positive hepatitis B virus carriers

Delta antigen is currently thought to reflect superinfection of the liver with a defective RNA virus (delta agent), requiring helper function from hepatitis B virus for its replication. To assess the influence of delta agent on hepatitis B virus replication in patients persistently infected with both viruses and showing chronic liver disease, we measured serum and liver hepatitis B virus DNA in HBsAg-positive chronic liver disease patients who were either positive or negative for delta antigen in the liver. Hepatitis B virus DNA was assayed in the serum of 21 patients with delta antigen-positive/HBsAg-positive chronic liver disease and in 21 patients with delta antigen-negative/HBsAg-positive chronic liver disease matched for HBeAg/anti-HBe status and underlying liver histology. HBcAg and delta antigen in liver was determined by immunofluorescence or immunoperoxidase staining. In delta antigen-positive/HBsAg-positive chronic liver disease, serum hepatitis B virus DNA was detected transiently in 4 of 21 cases (19%) and was present in these patients at low levels (trace to 2+). In contrast, 9 of 21 (43%) delta antigen-negative/HBsAg-positive chronic liver disease patients were serum hepatitis B virus DNA positive, and five of these had high serum hepatitis B virus DNA levels (3+ to 4+). Serum HBsAg and anti-HBc titers were significantly lower in delta antigen-positive cases and correlated with reduced amount of HBcAg in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)