[Autoimmune liver disease complicating Sjögren's syndrome]

Sjögren's syndrome (SjS) has been well known to complicate autoimmune liver diseases such as autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC). In addition, it has been recently described that chronic viral hepatitis type C could be accompanied by a sialadenitis resembling SjS. Among 98 patients with SjS at our clinic, 7 AIH, 1 PBC, and at least 11 hepatitis C virus (HCV) infection were noted. However, occurrence of SjS was not always associated with the severity of chronic liver diseases. Our present study suggested that three mechanisms might contribute to the pathogenesis of HCV-related SjS: 1) direct infection and proliferation of HCV in salivary glands, 2) molecular mimicry between HCV and salivary glands, and 3) formation of immune complex containing HCV. Further investigation would be indispensable to elucidate immunological systems to regulate these phenomena.