Lymphopoiesis of the Oral Mucosa

¹ Loyola University School of Dentistry, Chicago, Illinois

It may be proposed that in the oral mucosa the perivascular indifferent cells proliferate to give rise to immature lymphocytes by differentiation. The indifferent cells become committed to differentiate into lymphocytes under the influence of irritants which also induce a disaggregation of ground substance and loss of collagenous fibers. Thus the nature of the fibrous lamina propria is altered to accommodate the proliferation of perivascular cells. The perivascular cells thus organize the lymphatic follicle. While lymphocytes in the lamina propria may be in part blood-borne, the evidence presented in this report shows that the loose connective tissue can organize lymphatic follicles locally to produce lymphocytes. Thirteen specimens of human oral mucosa showing chronic inflammatory hyperplasia and containing lymphoid tissue in the lamina propria were examined by histochemical methods. Silver impregnation, PAS, RNA, toluidine blue metachromasia, and H. & E. staining procedures were employed. Mature lymphocytes did not contain either acid or neutral mucopolysaccharides; little or no RNA was seen in the cytoplasm. Reticulum cells and immature lymphocytes showed neutral polysaccharides and intensely staining RNA in their cytoplasm.