Hepatobiliary and pancreatic infections in AIDS: Part one

Cholangiocarcinoma - Part 2, Tumoral and Nontumoral Mimics and Imaging Features Helpful in Differentiation

Each of the 3 morphological subtypes of cholangiocarcinoma has a different set of imaging differentials. Emulators of mass-forming cholangiocarcinoma include other primary and secondary hepatic malignancies, benign tumors and tumor-like mimics such as abscess, hemangioma and confluent hepatic fibrosis. Benign inflammatory biliary strictures constitute the major differential of periductal-infiltrative type and intraductal calculi are the main consideration for intraductal-growth type. CT and MRI are the standard imaging tools for characterization of cholangiocarcinoma and differentiating it from close mimics. Here we will describe the various tumoral and non-tumoral mimics of cholangiocarcinoma and discuss specific imaging features useful in differentiation.

Beyond pyogenic liver abscess: a comprehensive review of liver infections in emergency settings

Hepatobiliary infections are commonly encountered in emergency settings ranging from common pathology such as pyogenic abscess to relatively uncommon and rare etiologies. Since extensive literature is already available on imaging of more common bacterial infections, for the sake of focused discussion, this review will discuss radiological appearance of less commonly encountered hepatic infections of fungal, parasitic, viral, and tubercular etiologies. Epidemiological and clinical information remain extremely important for obtaining more accurate presumptive diagnosis. In the era of diverse population migration, a modern-era radiologist must be well versed about the imaging spectrum of liver infections.

Prevalence of and progression to abnormal noninvasive markers of liver disease (aspartate aminotransferase-to-platelet ratio index and Fibrosis-4) among US HIV-infected youth

OBJECTIVE

To longitudinally characterize noninvasive markers of liver disease in HIV-infected youth.

DESIGN

HIV infection, without viral hepatitis coinfection, may contribute to liver disease. Noninvasive markers of liver disease [FIB-4 (Fibrosis-4) and APRI (aspartate aminotransferase-to-platelet ratio index)] have been evaluated in adults with concomitant HIV and hepatitis C, but are less studied in children.

METHODS

In prospective cohorts of HIV-infected and HIV-uninfected youth, we used linear regression models to compare log-transformed FIB-4 and APRI measures by HIV status based on a single visit at ages 15-20 years. We also longitudinally modeled trends in these measures in HIV-infected youth with two or more visits to compare those with behavioral vs. perinatal HIV infection (PHIV) using mixed effect linear regression, adjusting for age, sex, body mass index, and race/ethnicity.

RESULTS

Of 1785 participants, 41% were men, 57% black non-Hispanic, and 27% Hispanic. More HIV-infected than uninfected youth had an APRI score more than 0.5 (13 vs. 3%, P < 0.001). Among 1307 HIV-infected participants with longitudinal measures, FIB-4 scores increased 6% per year (P < 0.001) among all HIV-infected youth, whereas APRI scores increased 2% per year (P = 0.007) only among PHIV youth. The incidence rates (95% confidence interval) of progression of APRI to more than 0.5 and more than 1.5 were 7.5 (6.5-8.7) and 1.4 (1.0-1.9) cases per 100 person-years of follow-up, respectively. The incidence of progression of FIB-4 to more than 1.5 and more than 3.25 were 1.6 (1.2-2.2) and 0.3 (0.2-0.6) cases per 100 person-years, respectively.

CONCLUSION

APRI and FIB-4 scores were higher among HIV-infected youth. Progression to scores suggesting subclinical fibrosis or worse was common.

Sclerosing Cholangitis: Clinicopathologic Features, Imaging Spectrum, and Systemic Approach to Differential Diagnosis

Sclerosing cholangitis is a spectrum of chronic progressive cholestatic liver disease characterized by inflammation, fibrosis, and stricture of the bile ducts, which can be classified as primary and secondary sclerosing cholangitis. Primary sclerosing cholangitis is a chronic progressive liver disease of unknown cause. On the other hand, secondary sclerosing cholangitis has identifiable causes that include immunoglobulin G4-related sclerosing disease, recurrent pyogenic cholangitis, ischemic cholangitis, acquired immunodeficiency syndrome-related cholangitis, and eosinophilic cholangitis. In this review, we suggest a systemic approach to the differential diagnosis of sclerosing cholangitis based on the clinical and laboratory findings, as well as the typical imaging features on computed tomography and magnetic resonance (MR) imaging with MR cholangiography. Familiarity with various etiologies of sclerosing cholangitis and awareness of their typical clinical and imaging findings are essential for an accurate diagnosis and appropriate management.

Adult bile duct strictures: role of MR imaging and MR cholangiopancreatography in characterization

Bile duct strictures in adults are secondary to a wide spectrum of benign and malignant pathologic conditions. Benign causes of bile duct strictures include iatrogenic causes, acute or chronic pancreatitis, choledocholithiasis, primary sclerosing cholangitis, IgG4-related sclerosing cholangitis, liver transplantation, recurrent pyogenic cholangitis, Mirizzi syndrome, acquired immunodeficiency syndrome cholangiopathy, and sphincter of Oddi dysfunction. Malignant causes include cholangiocarcinoma, pancreatic adenocarcinoma, and periampullary carcinomas. Rare causes include biliary inflammatory pseudotumor, gallbladder carcinoma, hepatocellular carcinoma, metastases to bile ducts, and extrinsic bile duct compression secondary to periportal or peripancreatic lymphadenopathy. Contrast material-enhanced magnetic resonance (MR) imaging with MR cholangiopancreatography is extremely helpful in the noninvasive evaluation of patients with obstructive jaundice, an obstructive pattern of liver function, or incidentally detected biliary duct dilatation. Some of these conditions may show characteristic findings at MR imaging-MR cholangiopancreatography that help in making a definitive diagnosis. Although endoscopic retrograde cholangiopancreatography with tissue biopsy or surgery is needed for the definitive diagnosis of many of these strictures, certain MR imaging characteristics of the narrowed segment (eg, thickened wall, long-segment involvement, asymmetry, indistinct outer margin, luminal irregularity, hyperenhancement relative to the liver parenchyma) may favor a malignant cause. Awareness of the various causes of bile duct strictures in adults and familiarity with their appearances at MR imaging-MR cholangiopancreatography are important for accurate diagnosis and optimal patient management.

HIV infection of hepatocytes results in a modest increase in hepatitis C virus expression in vitro

Previous studies demonstrate that soluble HIV proteins impact both hepatocyte function and HCV replication in vitro. It has also been reported that HIV can productively infect hepatocytes. We therefore investigated the impact of HIV infection of hepatocytes on HCV expression. The Huh7.5_JFH1 cell line that constitutively expresses infectious HCV was infected with the lab-adapted strains HIV_NL4-3 or HIV_YK-JRCSF. HCV expression was quantified via HCV core antigen ELISA, Western blot, and strand-specific real-time PCR for positive-sense and negative-sense HCV RNA. After HIV_NL4-3 infection of Huh7.5_JFH1 cells, positive-sense and negative-sense HCV RNA levels were elevated compared to HIV uninfected cells. Increased HCV RNA synthesis was also observed after infection of Huh7.5_JFH1 cells with HIV_YK-JRCSF. HIV-induced HCV core production was decreased in the presence of the anti-HIV drugs AZT, T20, and raltegravir, although these medications had a minimal effect on HCV expression in the absence of HIV. HCV core, NS3, and NS5A protein expression were increased after HIV infection of Huh7.5_JFH1 cells. Chemically inactivated HIV had a minimal effect on HCV expression in Huh7.5_JFH1 cells suggesting that ongoing viral replication was critical. These data demonstrate that HIV induces HCV RNA synthesis and protein production in vitro and complement previous in vivo reports that HCV RNA levels are elevated in individuals with HIV/HCV co-infection compared to those with HCV mono-infection. These findings suggest that HIV suppression may be a critical factor in controlling liver disease, particularly if the underlying liver disease is not treated.

Low-level HIV infection of hepatocytes

BACKGROUND

There are only limited data on whether HIV infection occurs within the liver; therefore, we explored early and late stages of the HIV life cycle in two hepatocyte cell lines--Huh7.5 and Huh7.5JFH1--as well as in primary human hepatocytes.

RESULTS

Integrated HIV DNA was detected in Huh7.5 and Huh7.5JFH1 cells, as well as in primary hepatocytes, and was inhibited by the integrase inhibitor raltegravir in a dose-dependent manner. HIV p24 protein was also detected in cell culture supernatants at days 1, 3, 5, and 7 post-infection and was inhibited by AZT, although levels were modest compared to those in a lymphocyte cell line. Culture supernatants from HIV-infected hepatocytes were capable of infecting a non-hepatic HIV indicator cell line.

CONCLUSIONS

These results indicating low-level HIV replication in hepatoctyes in vitro complement evidence suggesting that HIV has deleterious effects on the liver in vivo.

HIV variability in the liver and evidence of possible compartmentalization

There is growing evidence to suggest that HIV may interact with several hepatic cell types; however, evaluation of HIV variability in liver tissue has not been addressed to date. Among 16 HIV-positive individuals examined, nine (56%) had detectable HIV RNA in the liver. The mean CD4 cell count for these nine individuals was 337 cells/mm(3) (range: 0-601), while their mean plasma HIV RNA level was 106,974 copies/ml (range: 1200-320,740). Among individuals in this study with detectable HIV in both the plasma and the liver, the consensus gag nucleotide sequences for each tissue type were different for seven of seven (100%) individuals, while amino acid sequences were distinct for five of seven (71%). Consensus envelope (env) nucleotide and amino acid sequences were also distinct in the plasma and liver tissue for six of six (100%) individuals. Statistical evidence of compartmentalization between HIV in the plasma and in the liver was demonstrated, and multiple liver-specific amino acids were identified that may distinguish HIV variants replicating within the liver. These preliminary data demonstrate that HIV is frequently detectable in the liver of HIV-positive persons at various levels of immunosuppression. Possible compartmentalization may reflect tissue-specific selection pressures that drive viral adaptation to the liver microenvironment and may facilitate interactions with other hepatotropic viruses.

HIV mono-infection is associated with FIB-4 - A noninvasive index of liver fibrosis - in women

BACKGROUND

FIB-4 represents a noninvasive, composite index that is a validated measure of hepatic fibrosis, which is an important indicator of liver disease. To date, there are limited data regarding hepatic fibrosis in women.

METHODS

FIB-4 was evaluated in a cohort of 1227 women, and associations were evaluated in univariate and multivariate regression models among 4 groups of subjects classified by their human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection status.

RESULTS

The median FIB-4 scores were 0.60 in HIV-/HCV- women, 0.83 in HIV-/HCV+ women, 0.86 in HIV+/HCV- women, and 1.30 in HIV+/HCV+ women. In the HIV/HCV co-infected group, multivariate analysis showed that CD4(+) cell count and albumin level were negatively associated with FIB-4 (P <.0001), whereas antiretroviral therapy (ART) was positively associated with FIB-4 score (P =.0008). For the HIV mono-infected group, multivariate analysis showed that CD4(+) cell count (P <.0001) and albumin level (P =.0019) were negatively correlated with FIB-4 score, ART was positively associated with FIB-4 score (P =.0008), and plasma HIV RNA level was marginally associated with FIB-4 score (P =.080). In 72 HIV mono-infected women who were also hepatitis B surface antigen negative, ART naive, and reported no recent alcohol intake, plasma HIV RNA level was associated with increased FIB-4 score (P =.030).

CONCLUSIONS

HIV RNA level was associated with increased FIB-4 score in the absence of hepatitis B, hepatitis C, ART, or alcohol use, suggesting a potential relationship between HIV infection and hepatic fibrosis in vivo. A better understanding of the various demographic and virologic variables that contribute to hepatic fibrosis may lead to more effective treatment of HIV infection and its co-morbid conditions.

Liver disease in the HIV-infected individual

Since the advent of effective antiretroviral therapy (ART) for human immunodeficiency virus-1 (HIV), there has been a substantial decrease in deaths related to acquired immunodeficiency syndrome (AIDS). However, in the ART era, liver disease is now the most common non-AIDS-related cause of death among HIV-infected patients, accounting for 14%-18% of all deaths in this population and almost half of deaths among hospitalized HIV-infected patients. Just as the burden of non-AIDS morbidity and mortality has changed in the ART era, the types of liver disease the clinician is likely to encounter among these patients have changed as well. This review will discuss the causes of liver disease in the HIV-infected population in the ART era, including chronic hepatitis C virus, chronic hepatitis B virus, medication-related hepatotoxicity, alcohol abuse, nonalcoholic fatty liver disease, and AIDS-related liver diseases.

HIV/AIDS cholangiopathy: clinical spectrum, cholangiographic features and outcome in 30 patients

BACKGROUND AND AIMS

AIDS cholangiopathy is presently considered rare and has been reported mainly from the West. With the HIV epidemic in India, we have encountered an increasing number of patients. We aimed to study these patients and determine differences from earlier experiences.

METHODS

We describe the clinical presentation, cholangiographic features, and outcome and determine differences reported in Western literature.

RESULTS

From Jan 1999 to May 2009, 30 patients (27 men) with AIDS cholangiopathy were seen. The most common mode of transmission was heterosexual (n = 28) followed by blood transfusion (n = 2). Abdominal pain (n = 20) of biliary origin, was the commonest manifestation followed by an asymptomatic group (n = 6) and a third group (n = 3) with pain due to pancreatitis. Ultrasonography of the abdomen was abnormal in all patients. Papillary stenosis (n = 23) was the most common cholangiographic feature followed by sclerosing cholangitis (n = 5). Abdominal pain resolved reliably and promptly after endoscopic sphincterotomy. Cholangiographic abnormalities regressed during follow up on antiretroviral therapy in 10 patients. Seven patients on anti retroviral therapy developed de novo cholangiopathy, with a precipitous drop in CD4 count of whom two had a worse prognosis. None had Kaposi's sarcoma.

CONCLUSIONS

In contrast to Western literature, HIV cholangiopathy was seen predominantly in patients who acquired HIV by heterosexual transmission. De novo development of cholangiopathy on antiretroviral therapy may indicate the occurrence of resistance. Papillary stenosis is the most common feature. Abdominal pain resolved with sphincterotomy. Regression of cholangiographic abnormality occurred with anti retroviral medications. Median survival following cholangiopathy diagnosis was 34 months, higher than reported in previous studies.

Hepatobiliary and pancreatic MRI and MRCP findings in patients with HIV infection

OBJECTIVE

The purpose of this article is to describe the spectrum of MRI and MR cholangiopancreatography (MRCP) findings of hepatic, pancreatic, and biliary manifestations in patients with HIV infection.

CONCLUSION

The spectrum of MRI and MRCP findings in HIV-infected patients includes acute or chronic hepatitis (or both), pancreatitis, cholangitis, acalculous cholecystitis, and biliary strictures that may resemble primary sclerosing cholangitis. The presence of segmental extrahepatic biliary strictures is characteristic of AIDS cholangiopathy.

Viral infections of the biliary tract

Bacterial infections of the biliary tract are often considered to be an important cause of acute cholangitis. Viral infections of the biliary tract however, are very often mistaken as viral hepatitis. This article highlights various viral causes of common biliary tract infections. Viral cholangitis is both less common and less discussed than viral hepatitis. Hepatotropic viruses (A, B, C, and E) are generally regarded as hepatocellular pathogens, yet cholangitic manifestations are now well described in association with these diseases. Systemic viral diseases also lead to cholangitis in varying proportion to hepatitis. Human immunodeficiency virus is associated with protean hepatic complications, including cholangitis due to several causes. Other systemic viruses, most notably those of the herpes virus family, also cause hepatic disease including cholangitis and possibly ductopenia in both immunocompromised and immunocompetent patients.

Acute pancreatitis associated with different combination therapies in patients infected with human immunodeficiency virus

STUDY OBJECTIVE

To assess the risk of acute pancreatitis in patients receiving various combinations of protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs), and nonnucleoside reverse transcriptase inhibitors (NNRTIs) for treatment of human immunodeficiency virus (HIV) infection.

DESIGN

Retrospective cohort study.

DATA SOURCE

Ohio Medicaid claims database, January 1997-December 2002.

PATIENTS

Four thousand nine hundred seventy-two patients with HIV infection who had received at least one antiretroviral drug.

MEASUREMENTS AND MAIN RESULTS

Three combination regimens were evaluated: didanosine plus other antiretroviral agents, protease inhibitors plus NRTIs or NNRTIs, and NRTI combinations (no didanosine) or NRTIs plus NNRTIs. We used Cox proportional hazard regression and Kaplan-Meier plots to examine the risk for acute pancreatitis. We identified 159 (3.2%) cases of acute pancreatitis during the study period. For patients who were newly treated for HIV, the incidence of acute pancreatitis was 1.95/100 person-years. Half of these cases developed within 500 days of the start of drug therapy. Hazard ratios (HRs) for acute pancreatitis were 39-54% higher for nonwhite patients than Caucasians and 240-290% higher for symptomatic versus nonsymptomatic patients. Hazard ratios also were significantly associated with increased age, liver injuries (HR 2.94, 6.73), and cardiovascular diseases (HR 1.68, 2.36), respectively, for both newly treated and previously diagnosed patients with HIV. The risk for patients receiving either protease inhibitors plus an NRTI or an NNRTI, or NRTI plus NNRTI combinations was not significantly different from the risk associated with didanosine combination therapy (p>0.10).

CONCLUSION

The risk of acute pancreatitis was significantly associated with age, race, symptomatic HIV infection, and liver and cardiovascular diseases. However, risk did not differ significantly among patients with different antiretroviral regimens. Our results can be used by the medical community to enhance patient safety and minimize costly adverse drug reactions among patients with HIV infection.

Innate immune responses to adenoviral vector-mediated acute pancreatitis

OBJECTIVES

The role of innate immunity in the development of acute viral pancreatitis is not well understood. The aim of the study was to characterize the role of the innate immune system, especially macrophages, natural killer (NK), and NK T (NKT) cells, in the generation of immune responses to intrapancreatic delivery of recombinant adenoviral vector.

METHODS

Adenoviral vectors expressing beta-galactosidase or green fluorescent protein genes with viral capsid conjugated covalently with carbocyanine dye were directly injected into the pancreas of C57Bl/6 mice.

RESULTS

Fluorescent microscopy of the pancreas showed that 30 minutes after vector administration, adenoviral particles localized to cell membranes, internalized, and localized to the nucleus by 4 hours, and transgene expression began at 24 hours. Immunohistochemical staining showed macrophages entering the pancreas shortly after vector administration, with maximal infiltration at day 4, and then disappearing as antigen-expressing cells were eliminated. Intrapancreatic macrophages appeared to deliver viral capsid proteins to the spleen. Flow cytometry showed that NK and NKT cells migrate to the pancreas and persist. Serum cytokines IL-6, IL-10, and IL-12 were all elevated.

CONCLUSION

Macrophages and NK and NKT cells play a major role in the development of acute adenovirus-mediated pancreatitis.

The infected liver: radiologic-pathologic correlation

Recent technologic advances have significantly enhanced the role of imaging in the detection, characterization, and management of infectious diseases involving the liver. In addition, imaging-guided percutaneous drainage has greatly improved the clinical treatment of patients with focal liver abscess. Infectious liver diseases can be accurately evaluated with ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Characteristic changes in US echogenicity, CT attenuation, or MR imaging signal intensity and typical enhancement patterns can contribute to the diagnosis of specific infectious diseases, including abscesses, parasitic diseases, fungal diseases, granulomatous diseases, viral hepatitis, and other less common infections. CT is particularly helpful in revealing the presence of calcifications and gas and in detailing the enhancement pattern. The multiplanar capability of MR imaging and its sensitivity to small differences in tissue composition increase its specificity for certain hepatic infections, including hydatid cyst and candidiasis. Radiologic findings may be sufficient to obviate aspiration or histologic examination, although in most instances they are less specific. Nevertheless, imaging findings taken together with appropriate clinical information may provide the most likely diagnosis, even if biopsy is sometimes required for confirmation.

The role of CFTR and SPINK-1 mutations in pancreatic disorders in HIV-positive patients: a case-control study

OBJECTIVE

Pancreatic disorders in HIV-positive patients are frequent. CFTR and SPINK-1 mutations have been reported to increase the risk of pancreatitis, but no data are available in HIV-positive patients. This study will evaluate the frequency of CFTR mutations and SPINK-1 polymorphisms in HIV-positive patients with clinical pancreatitis or asymptomatic elevation of serum pancreatic enzymes.

METHOD

Cases (patients with hyperamylasemia) were identified during a toxicity study conducted in August 1999 among 1152 participants of the Swiss HIV Cohort Study. We designed a case-control study in which each case was matched one to one to an HIV-infected control according to sex, age, CD4 cell count, viraemia and medication use. CFTR mutations and SPINK-1 polymorphisms were studied using polymerase chain reaction techniques.

RESULTS

Fifty-one HIV-positive patients with hyperamylasemia were detected among 1152 participants in the toxicity study (4.4%). There were 13 carriers of CFTR and SPINK-1 mutations (12.7%). Amylase levels were 316 +/- 130 U/l for the group with mutations, and 135 +/- 18 U/l for non-carriers (P = 0.79). However, among patients with hyperamylasemia, those with CFTR or SPINK-1 mutations had 648 +/- 216 U/l amylase levels compared with 232 +/- 28 U/l for those without (P = 0.025). Ten patients had acute pancreatitis, four of whom had CFTR mutations or SPINK-1 polymorphisms (40%) compared with seven of the control patients (14%) (P = 0.01).

CONCLUSION

CFTR mutations and SPINK-1 polymorphisms are frequent among HIV-positive patients suffering from acute pancreatitis. These mutations may increase the susceptibility to pancreatitis when exposed to environmental risk factors.

Hepatitis viruses and hepatocellular carcinoma in HIV-infected patients

Hepatocellular carcinoma, the most common primary cancer of the liver, results in significant morbidity and mortality. Several disease entities have been shown to predispose to hepatocellular carcinoma. In most cases, however, hepatitis B virus, hepatitis C virus, and cirrhosis are the principal etiologic factors. In HIV-positive patients, a significant increase in the incidence of certain malignancies has been noted. Although HIV and the hepatitis viruses share common modes of transmission, an increase in the incidence of hepatocellular carcinoma in the patients with HIV has not been observed. This finding may be a function of premature death in patients with HIV before the advent of effective antiretroviral therapy. The introduction of such therapy may alter the epidemiology of hepatocellular carcinoma and strain health services, because current treatment options targeting both the underlying causative viruses and liver cancer itself are unsatisfactory and are the subject of ongoing research.