Table 2.

Key clinical features and immune involvement in liver diseases.

Disease	Clinical features	Immune involvement	References
Alcohol related liver disease (ArLD)	Hepatocyte damage Steatosis Fibrosis Cirrhosis Lipogenesis Accumulation of fat in the liver High levels of IgA, IgG and IgM Lipopolysaccharide circulation Portal and lobular inflammation	Liver inflammation Altered B cell compartment Increased plasmablasts Decreased regulatory B cells Reduction in circulating B cells	(86, 103–108)
Non-alcoholic fatty liver disease (NAFLD)	Steatosis Hepatic inflammation Fibrosis Hepatocyte damage Cirrhosis Lipid influx Portal and lobular inflammation Altered distribution of adipose tissue Elevated levels of endotoxin Raised IgG titres	Liver inflammation Damage by reactive oxygen species, lipotoxicity and inflammatory mediators Infiltration of activated immune cells Increased B cells associated with disease severity Ectopic B and T cell aggregates LPS stimulates B cells to secrete inflammatory mediators	(80, 86, 114–118)
Viral hepatitis	Antibodies against viral epitopes Formation of immune complexes	Progressive inflammation and liver damage Accumulation of circulating B cells within the liver Elevated levels of activated B cells Dysfunctional B cells Expansion of exhausted memory B cells Enrichment of atypical B cells Increase in IL-10 producing regulatory B cells B cells can act as vehicles for HCV transmission	(71, 75, 121–123, 131, 133, 134, 136, 138, 139)
Autoimmune hepatitis (AIH)	Associated with other autoimmune diseases Necro-inflammatory disease Destruction of the hepatic parenchyma and hepatocytes Fibrosis Cirrhosis	Increased immune infiltration Presence of autoantibodies Elevated serum IgG levels B cells are primed to co-stimulate T cells via CD86 interaction	(154, 159, 162, 164, 166)
Primary sclerosing cholangitis (PSC)	Fibrosis Destruction of the large bile ducts Associated with IBD Cirrhosis Destruction of the biliary tree Defects in intestinal barrier Altered gut microbiota	Presence of autoantibodies High numbers of B cells IgG4+ plasma cell aggregates and deposits in some PSC patients	(64, 157, 168–170, 172, 177)
Primary biliary cholangitis (PBC)	Affects small bile ducts Fibrosis Accumulation of bile toxins Presence of several bacterial products	Immune-mediated destruction of intrahepatic small bile ducts Liver inflammation Loss of B cell tolerance Presence of autoantibodies Hyper-IgM expression in the serum Complement activation via agglutination by IgM	(83, 157, 179, 181, 184, 186)
Biliary atresia	Progressive liver damage Obliteration of the extrahepatic biliary tree and hepatic ducts Fibrosis Cirrhosis	Increased immune infiltration Elevated lymphocyte activation in the portal tracts Increased presence of intrahepatic periductal B cells IgM and IgG deposits High levels of high-affinity pathogenic IgG antibodies Autoantibodies may be present	(190, 191, 193, 199, 201, 207)

A brief summary of the clinical features and immune compartment involvement in adult and paediatric liver diseases.