[5][6] Similarly, the Bgee consortium,[10] using multiple techniques in addition to RNA-Seq, reports a relative Expression Score of 95.8 out of 100 for testis and 99.0 for sperm in humans; however low levels of BPIFA3 between 20 and 30 were seen for a variety of tissues such as muscle, glands, prostate, nervous system, and skin.

[13] The BPI fold creates apolar binding pockets that can interact with hydrophobic and amphipathic molecules, such as the acyl carbon chains of lipopolysaccharide found on Gram-negative bacteria, but members of this family may have many other functions.

Due to its high degree of similarity to other members of the BPI/LBP/PLUNC superfamily, it is predicted to have binding activity to lipids such as phospholipids and lipopolysaccharides but this has never been confirmed.

Despite a near-exclusive expression of BPIFA3 in testis, only a single report implicates it in any normal or pathological states and that involves Otitis media (OM) in the ear.

[19] OM is a common disease of early childhood characterized by inflammation of the middle ear cavity and an effort was made to identify genetic risk factors.