MUC5AC and argyrophilic grain disease: Th2 cytokines (mostly IL13) in mammals are known to stimulate goblet cell hyperplasia and overexpression of Muc5AC and/or Muc5B32,33,46, and the distinct pattern of muc5 and il4/13a and il4/13b2 expression detected in AGD may indicate a similar mechanism in fish.