Distribution of plasma cells in normal rectal mucosa.

In a survey of 36 histologically normal rectal biopsies, plasma cell counts were recorded at different depths of the lamina propria. The necessity of surveying the lamina propria at every level from the muscularis mucosae to the epithelium, in order to obtain an accurate estimate of plasma cell frequency is demonstrated. The relative accuracy of counting smaller areas of lamina propria is tested and the ratio of epithelium to lamina propria area established.