In pernicious anemia, which antibody is characteristically detected?

In pernicious anemia, the characteristic antibody detected is the anti-parietal cell antibody. Pernicious anemia is an autoimmune disorder that leads to a deficiency of vitamin B12 due to the impaired absorption of this essential nutrient. This impairment is primarily caused by the destruction of gastric parietal cells, which are responsible for producing intrinsic factor. Intrinsic factor is vital for the absorption of vitamin B12 in the intestines.

The presence of anti-parietal cell antibodies indicates that the immune system is targeting the body's own parietal cells, an autoimmune response that interferes with intrinsic factor production. This ultimately results in reduced vitamin B12 absorption, leading to the manifestations of pernicious anemia, including megaloblastic anemia and neurological symptoms.

The other antibodies listed, such as anti-mitochondrial (associated with primary biliary cholangitis), anti-thyroid peroxidase (related to autoimmune thyroid disorders), and anti-nuclear (commonly seen in systemic lupus erythematosus and other autoimmune diseases), are not specifically associated with pernicious anemia. Each of these antibodies pertains to different autoimmune conditions, highlighting the specificity of the anti-parietal cell antibodies in diagnosing pernicious anemia.