Intrinsic factor antibodies

Gastric intrinsic factor is a secreted glycoprotein, such as hydrochloric acid, by the fundic cells of the stomach.
In combination with vitamin B12 from food, it forms a complex which binds to specific receptors on the ileum, which allows the absorption of vitamin B12 in the small intestine.
Of intrinsic factor antibodies appear in the pernicious anemia, which is a autoimmune atrophic gastritis.
Each block the binding of intrinsic factor to vitamin B12 (type I); others bind to the complex intrinsic factor-vitamin B12, preventing its attachment to the ileal receptor (type II).

Indications:

Diagnosis of pernicious anemia suspected in megaloblastic anemia.

Sample:

Venous blood collected in a dry tube.

Typical values:

Type I antibodies are absent in normal subjects.

Interpretation:

The intrinsic factor autoantibodies blocking type I are specific for pernicious anemia. Associated with a decrease of the concentration of vitamin B12 (<150 ng / L), they provide the diagnosis.