Epithelia, stoma and leukocytes can be isolated using CD45 and CD326. Epithelia are CD326Pos/CD45Neg, leukocytes are CD45Pos/CD26Neg, while stroma are double negative for these markers. Stroma can be separated into endothelia and fibromuscular stroma with CD31. Endothelia are CD31Pos while fibromuscular stroma are CD31Neg. Epithelia can also be divided into basal and luminal epithelia using the basal marker CD271 and the luminal marker CD26.