[6] Orthologs are present in many vertebrate species including mammals, birds, reptiles, and amphibians.

[9] 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.

This all points to a role for BPIFB6 in secretory pathway trafficking, which was further illustrated by its effects on viral replication.

Viruses such as coxsackievirus B (CVB) and poliovirus (PV) co-opt the host cell's secretory pathway, which controls the transport of proteins from the endoplasmic reticulum to the Golgi complex, to facilitate their replication.

[14] Also, tonsils which are mucosal lymphatic tissues, can become enlarged (hypertrophic) following inflammation from infection and recurrent pharyngitis (sore throat).