Gastric parietal and liver autoantibodies

 

Alternative names, keywords

anti GPC, anti IF, anti LKM

Samples required

Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

Test indications

Investigation of pernicious anaemia and autoimmune liver disease.

Test information

These tests are performed by indirect immunofluorescence, and all these antibodies can be detected on a single slide.

Ideally the specific antibody relevant to the clinical features under investigation should be requested - see below for details on gastric parietal cell, mitochondrial, smooth muscle, and liver kidney microsomal antibodies.

As with all autoantibody testing these may be positive in healthy individuals and may be non-specific. Thus the tests should only be requested with specific reference to the clinical condition. In general the value of these tests is limited to the investigation of pernicious anaemia and autoimmune liver disease.

Turnaround time

Tests are performed 3 times per week. Turnaround time is 4 days.

Turnaround time for intrinsic factor antibody is 7 days.

Enquiries

Immunology

 

Gastric parietal cell (GPC) antibody

These are present in individuals with autoimmune gastritis and pernicious anaemia. However they are not specific for these conditions, as they may be also found in healthy individuals, particularly with increased age, and in those with other autoimmune conditions (thyroiditis, Addison’s disease, IDDM). If vitamin B12 levels are low then intrinsic factor (IF) antibody should be requested in addition to gastric parietal cell antibodies. GPC antibody is more sensitive but less specific for pernicious anaemia than IF antibody.

Mitochondrial antibody (M2)

These antibodies are directed to pyruvate dehydogenase complex and have a close association with primary biliary cirrhosis (PBC). When these are positive for the first time then the sample will be reflex tested for anti-PDH E2 (M2) antibodies to confirm the antibody specificity.

Smooth muscle antibody

These are frequently non-specific or transiently detected. However they may be associated with type 1 autoimmune hepatitis. These patients may also have a positive ANA.

Liver, kidney microsomal (LKM) antibody

These are directed against cytochrome P450 proteins and are particularly associated with type 2 autoimmune hepatitis. This form of AIH presents more commonly in children.