MAPT and pelvic inflammatory disease: Compared to PHFs and SFs observed in the brains of individuals with AD, the core element of filaments in the brains of individuals with PiD are comprised of residues K254-F378 of 3R tau isoforms which lack the 2nd repeat (R2; 275–305; numbering according to 2N/4R tau) and both narrow and wide filaments are observed by cryo-EM (Falcon et al., 2018a).