Prenatal and postnatal changes of the human tonsillar crypt epithelium.

The tonsillar crypt shows infiltration of lymphoid cells in the epithelium and the highly porous or discontinuous basement membrane. However, the relationship between developmental period and the significance of the disrupted epithelial basement membrane and infiltration of lymphoid cells within the human tonsillar crypt epithelium is still obscure. The present study was designed to determine the prenatal and postnatal changes of the human tonsillar crypt epithelium in 4 fetuses, 4 neonates, 1 infant, 5 children and 4 adults using immunohistochemical stains with polyclonal anti-laminin and monoclonal anti-type IV collagen antibody, and transmission electron microscope. The tonsillar crypt epithelium from all fetuses and neonates showed infiltration of many lymphoid cells and an intact basement membrane by immunohistochemistry. Transmission electron microscope revealed pores in the basement membrane through which lymphocytes passed. Tonsils from a 4-month-old infant showed focal disruption of the basement membrane by immunohistochemical staining. The tonsils from children and adults showed that there was massive disruption of the basement membrane with lymphoid cell infiltration in the tonsillar crypt epithelium by immunohistochemical staining and transmission electron microscopy. In conclusion, lymphoid cell infiltration and holes of the basement membrane of the tonsillar crypt epithelium are normal developmental findings, whereas disruption of the basement membrane of the tonsillar crypt epithelium is pathological.