Autoimmune liver disease - are there spectra that we do not know?

Autoimmune liver diseases (AILD) are a group of immunologically induced hepatic damage that are either hepatocellular or cholestatic [1,2]. The hepatocellular forms are characterized by a significant elevation of the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as compared with the biliary enzymes, together with elevated serum bilirubin. The cholestatic forms involve either the intra- or the extra-hepatic biliary systems or both. Cholestasis will ultimately cause impairment of bile formation and/or bile flow which may clinically present with fatigue, pruritus, and jaundice [1,2]. The biochemical markers include increases in serum alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (GGT), followed by conjugated hyperbilirubinemia, at more advanced stages. Cholestasis is considered chronic if it lasts more than 6 months [3]. Most chronic cholestatic diseases are purely intra-hepatic [3,4]. They are considered as different disease entities based on the clinical, laboratory and histological features [3,4]. In many instances, however, some of the histological and or the pathological features of one AILD disease may follow another; in addition, the two disease entities may coexist in the same patient [3,4]. Those forms of presentations are defined as overlap syndromes (OS) [3,4]. The presence of the overlap patterns of cholestatic liver disease suggests that those diseases may represent spectra of a common or similar immunological and pathological process that causes the hepatobiliary damage [1,5].Autoimmune hepatitis (AIH) is a chronic relapsing remitting necroinflammatory disease associated with elevation of the serum immunoglobulins and autoantidobies [2,6]. The disease mostly affects children and young adults, but can also affect older people [7-9]. AIH has various clinical presentations from asymptomatic disease to advance liver cirrhosis or severe forms of acute liver failure [6-9]. The usual biochemical presentation of AIH is