IMMUNOLOGY

Detailed explanation-1: -In type III hypersensitivity reactions, an abnormal immune response is mediated by the formation of antigen-antibody aggregates called “immune complexes."[1] They can precipitate in various tissues such as skin, joints, vessels, or glomeruli and trigger the classical complement pathway.

Detailed explanation-2: -Type 3 immunity is characterized by the recruitment of neutrophils and the stimulation of epithelial antimicrobial defenses at infection sites. Type 3 immunity is often triggered by extracellular bacteria and fungi and seems to be particularly suited to defend epithelial barriers against these pathogens.

Detailed explanation-3: -Examples of Type III hypersensitivity reactions include systemic lupus erythematosus, rheumatoid arthritis, and serum sickness. Symptoms can vary depending on the tissues affected and may include joint pain and swelling, rashes, fever, and kidney damage.