Hepatitis A Virus-associated Cholecystitis

Cholestatic hepatitis [1] and cholecystitis [2, 3] are poorly recognized manifestations of acute hepatitis A virus (HAV) infection. Although previous studies showed that HAV-associated RNA and antigen are present predominantly in hepatocytes and, to a lesser extent, in Kupffer cells, the pathogenesis of these abnormalities remains unknown [4]. To understand better the mechanisms of HAV-associated cholestasis and cholecystitis, we did an immunohistochemical analysis of liver and gallbladder specimens from an elderly patient with cholestatic hepatitis A and acalculous cholecystitis. A microscopic examination revealed portal inflammation and pericholangitis as well as cholestasis in the liver and lymphocytic cholecystitis. In contrast to weak staining in approximately 30% of hepatocytes, intense cytoplasmic staining of HAV antigen was detected in the epithelium of both the intrahepatic bile ducts and the gallbladder. These findings suggest that HAV can directly infect biliary epithelium and that such an infection may have an important role in the pathogenesis of cholestasis and gallbladder abnormalities in patients with acute HAV infection. Table 1. Laboratory Findings in a Patient with Hepatitis A Virus-associated Cholecystitis through the Course of His Illness Case Report A 68-year-old white man was hospitalized with a 3-day history of fever, chills, nausea, and vomiting and was diaphoretic, hypotensive, and slightly icteric. His laboratory values are shown in Table 1. Because sepsis was suspected, intravenous fluids and antibiotics were administered. Sonography showed marked thickening of the gallbladder wall with no stones. Cholecystitis with ascending cholangitis was considered, and the patient was transferred to our institution on hospital day 4. An endoscopic retrograde cholangiopancreatogram showed a normal intrahepatic and extrahepatic biliary system but markedly thickened gallbladder mucosa. A laparoscopic cholecystectomy and liver biopsy were done. Results of subsequent serologic studies showed specific IgM anti-HAV antibodies. The patient was discharged in stable condition 18 days after his initial admission; on follow-up at 2 weeks and at 4 weeks, he was asymptomatic, and his biochemical markers of cholestasis had gradually improved. The enhanced biotin-streptavidin method (StrAviGen Super Sensitive Alkaline Phosphatase kit, BioGenex Laboratories; San Ramon, California) and highly specific monoclonal antibodies against HAV antigen (BioGenex Laboratories) were used to detect HAV antigen immunohistochemically. The specificity of the reaction was confirmed by analyzing negative control tissues (liver biopsy specimens infected with hepatitis B and C viruses and gallbladders removed because of calculous cholecystitis) and HAV-producing cell lines. A microscopic examination of the liver showed severe, predominantly lymphocytic portal inflammation, lobular disarray, hepatocyte ballooning, and focal necrosis. Intrahepatic cholestasis and ductular epithelial injury with lymphocytic inflammation and ductular proliferation were present. Immunohistochemical analysis showed faint cytoplasmic staining in approximately one third of the hepatocytes. In contrast, an intense cytoplasmic signal was detected in the epithelial cells of the biliary ducts (Figure 1, top left) and in the ductules and pseudoducts (Figure 1, top left and right). Figure 1. Immunostaining for antigen associated with hepatitis A virus in the liver and gallbladder from a patient with acute hepatitis A. top left top right bottom left bottom right The gallbladder was mildly edematous and hemorrhagic. No stones were found. A microscopic examination showed an architecturally normal epithelium with numerous intraepithelial lymphocytes. A moderate lymphocytic infiltrate with rare eosinophils and almost no neutrophils was present in the lamina propria. Hepatitis A virus antigen was present in most epithelial cells (Figure 1, bottom left) and was located predominantly in the supranuclear areas (Figure 1, bottom right). Discussion Previous studies in humans have shown HAV antigens and RNA only in hepatocytes and Kupffer cells [5-8]. However, the occurrence of cholecystitis in association with acute HAV infection [2, 3] and the recurrence of hepatitis A after liver transplantation [9] suggest that HAV might infect cells other than hepatocytes. Although HAV replication in cells of extrahepatic origin was documented in various cell lines and in several animal models [4], the presence of extrahepatic HAV infection and, specifically, infection of the biliary epithelium have not been shown previously in humans. We showed that HAV can directly infect the biliary epithelium of the gallbladder and the intrahepatic and extrahepatic bile ducts. Gallbladder wall thickening is commonly noted during sonographic examination in patients with acute viral hepatitis [10]. Further, acalculous cholecystitis has been reported in children with acute hepatitis A [2, 3]. Our observation indicates that HAV can infect both gallbladder and bile duct epithelium. It is possible that such a direct infection of the biliary epithelium may have a direct role in the pathogenesis of HAV-associated cholangiopathic infection. Both clinical and experimental data indicate that HAV-induced liver injury is mediated by immunologic mechanisms [4]. In our patient, the inflammatory infiltrate around and within the biliary epithelium consisted almost exclusively of lymphocytes. This finding suggests that cell-mediated immunity may also have a role in the pathogenesis of hepatitis-A-associated cholangiopathies. Further, the presence of HAV within epithelial cells of the biliary tract may provide insights into the mechanisms by which the virus is exported to the bile and excreted with the feces.