%0 Journal Article %T Clinical Features of Adult Patients with Acute Hepatitis B Virus Infection Progressing to Chronic Infection %A Kojiro Michitaka %A Atsushi Hiraoka %A Yoshio Tokumoto %A Keiko Ninomiya %A Tomoyuki Ninomiya %A Norio Horiike %A Masanori Abe %A Yoichi Hiasa %J International Journal of Hepatology %D 2014 %I Hindawi Publishing Corporation %R 10.1155/2014/358206 %X Background. Information regarding the progression of acute hepatitis B virus (HBV) infection to chronic infection in adults is scarce. Methods. Twenty-five adult patients with acute HBV infection (14 men and 11 women, 18每84 years old), whose clinical features progressed to those of chronic infection (group A) or did not (group B), were studied retrospectively. Results. There were 3 and 22 patients in groups A and B, respectively. Two of the 3 patients of group A lacked the typical symptoms of acute hepatitis. No differences were found between groups with respect to age, sex, or HBV genotypes. However, total bilirubin and alanine aminotransaminase levels were significantly lower in group A. Conclusions. Three of the 25 adult patients with acute HBV infection progressed to chronic infection. Hepatitis was mild in these patients. Patients with mild acute hepatitis B or unapparent HBV infection may have a higher risk of progressing to chronic infection. 1. Introduction Hepatitis B virus (HBV) is a DNA virus with approximately 3200 base pairs. Approximately 350每400 million people are chronically infected with HBV and more than 3 billion people have been exposed to HBV worldwide [1, 2]. HBV induces a variety of liver diseases, ranging from acute or fulminant hepatitis to liver cirrhosis and hepatocellular carcinoma. HBV is one of the most important causes of liver cirrhosis and hepatocellular carcinoma [3]. On the other hand, hepatitis is self-limited in most adult patients with acute infection. Meanwhile 1-2% of patients progress to fulminant hepatic failure, and some progress to chronic infection. The rate of progression from acute to chronic HBV infection is reported to be 90% in newborns and 5每10% in adults [4, 5]. HBV can be classified into at least 8 genotypes with a divergence of more than 8% of nucleotide sequences [6每8]. There are some differences in clinical features and routes of transmission between genotypes [9, 10]. The rate of chronicity of genotype A infections is reported to be higher than those of other genotypes [11每14]. The progression of acute hepatitis B to chronic hepatitis is not rare in Western countries, but it is rare in Japan. The differences of the rates of chronicity of acute HBV infection supposed to be attributable to the different distribution of HBV genotypes; genotypes B and C are the predominant genotypes while genotype A was rare in Japan and common in Western countries. However, previous studies are based on the follow-up studies of apparent acute hepatitis B. The present study aimed to clarify the progression to chronic %U http://www.hindawi.com/journals/ijh/2014/358206/