MRCP UK EXAMINATIONS

Detailed explanation-1: -Serum IgA molecules are mostly monomeric, while secretory IgA molecules are found as dimers and, to a lesser extent, as trimers and tetramers.

Detailed explanation-2: -Immunoglobulin A (IgA) is the most abundant type of antibody in the body, comprising most of the immunoglobulin in secretions and a significant amount of circulating immunoglobulin. In secretions, it serves to protect the mucosal tissues from microbial invasion and maintain immune homeostasis with the microbiota.