BPI fold containing family A, member 1 (BPIFA1), also known as Palate, lung, and nasal epithelium clone (PLUNC),[5] is a protein that in humans is encoded by the BPIFA1 gene.[6][7] It was also formerly known as "Secretory protein in upper respiratory tracts" (SPURT). The BPIFA1 gene sequence predicts 4 transcripts (splice variants); 3 mRNA variants have been well characterized. The resulting BPIFA1 is a secreted protein, expressed at very high levels in mucosa of the airways (olfactory and respiratory and epithelium) and salivary glands; at high levels in oropharyneal epithelium, including tongue and tonsils; and at moderate levels many other tissue types and glands including pituitary, testis, lung, bladder, blood, prostate, pancreas, levels in the digestive tract (tongue, stomach, intestinal epithelium) and pancreas.[8] The protein can be detected on the apical side of epithelial cells and in airway surface liquid, nasal mucus, and sputum.[9]