PIGR and selective IgA deficiency disease: This infers that some subjects might have impaired nasal immune response so that either there were no inductions at the lamina propria, or intrinsic IgA deficiency (23), or the IgA produced did not undergo transcytosis by the polymeric immunoglobulin receptor (pIgR) and therefore, no secretory IgA was detected in the NELF of these subjects (24).