Anti-myeloperoxidase antibody positivity

What it means

The presence of autoantibodies in the blood circulation that react against myeloperoxidase.

MPO-ANCA are host-derived autoantibodies against shielded neutrophilic antigens. These antibodies react against primary granules present in neutrophils and monocytes. The formation of these antibodies has been hypothesized to be a two-step process. The first step involves exposure of neutrophils to inflammatory cytokines leading to surface exposure of cryptogenic antigens like myeloperoxidase or MPO. Next, predisposing genetic, environmental, and other factors result in the production of MPO-ANCA. In the second step, these MPO-ANCA cause damage to the host vasculature by reacting and crosslinking neutrophils to the endothelial receptors.

Rare diseases that can present with this4

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Anti-MPO antibody positivity · Anti-myeloperoxidase specific antineutrophil cytoplasmic antibody · MPO-ANCA