My Laboratory discovered and cloned the polymeric immunoglobulin receptor (PIGR), and worked out the pathway by which it transcytoses 3g/day of IgA into mucosal secretions. This IgA regulates the mucosal biome, playing a vital role in preventing mucosal diseases such as diarrhea and pneumonia. We showed how mutations in PIGR are causal in nasopharyngeal carcinoma, a major cause of cancer deaths in South East Asia, and in IgA Nephropathy, the major cause of end stage renal failure world wide.