Hereditary angioneurotic edema (HANE) & Immunodeficiencies in phagocyte function

What causes hereditary angioneurotic edema (HANE)?

HANE is caused by mutations in the C1 inhibitor (C1-INH) gene.

What is the role of C1-INH in the immune system?

C1-INH normally binds and inactivates the proteases associated with the C1 complex, regulating complement activation.

How does a deficiency in C1-INH lead to edema in HANE?

Overactivity of C1 in the absence of C1-INH leads to depletion of C2 and C4 proteins and high levels of C2a, a potent vasodilator.

This, along with C1-INH's effects on clotting factors like bradykinin, results in edema.

What are the causes of immunodeficiencies in phagocyte function?

Immunodeficiencies in phagocyte function can be due to a lack of specific immune cells or mutations affecting pathways important for phagocytic destruction.

How do defects in NADPH oxidase affect phagocyte function?

Defects in NADPH oxidase or proteins involved in the oxidative burst impair the ability of phagocytes to kill bacteria, resulting in increased susceptibility to infections.

What is neutropenia and how does it affect immune function?

Is a condition characterized by a deficiency in neutrophils, impairing the body’s ability to respond to microbial infections.