Chronic immune complex diseases involve which phenomenon?

Chronic immune complex diseases involve which phenomenon?

• A. Overreaction to antigen present
• B. Immunodeficiency after radiation
• C. Depression of the immune system after radiation
• D. Accumulation of antigen-antibody complexes in the bloodstream

Answer: (D)

Immune complex diseases are driven by circulating antigen–antibody complexes that aren’t cleared effectively. These immune complexes accumulate in the bloodstream and then deposit in tissues such as blood vessel walls and organ basement membranes (for example, in the kidneys and joints). Once deposited, they activate complement and recruit inflammatory cells, leading to ongoing inflammation and tissue injury. This is a classic example of a Type III hypersensitivity reaction. The other statements describe exaggerated responses to antigens without the circulating complexes or immune suppression from radiation, which aren’t the defining feature of chronic immune complex diseases.

Immune complex diseases are driven by circulating antigen–antibody complexes that aren’t cleared effectively. These immune complexes accumulate in the bloodstream and then deposit in tissues such as blood vessel walls and organ basement membranes (for example, in the kidneys and joints). Once deposited, they activate complement and recruit inflammatory cells, leading to ongoing inflammation and tissue injury. This is a classic example of a Type III hypersensitivity reaction. The other statements describe exaggerated responses to antigens without the circulating complexes or immune suppression from radiation, which aren’t the defining feature of chronic immune complex diseases.