Plasma cells and immunoglobulin-synthesis in oral precancer and cancer. Correlation with dysplasia, cancer differentiation, radio- and chemotherapy.

The subepithelial and peritumoral inflammatory infiltrates of 202 oral premalignant and malignant lesions -- 108 leukoplakias and 94 squamous cell carcinomata with different grades of dysplasia were examined using an immunoenzymatic method. In addition, the influence of radiation and bleomycin-therapy on the stromal reaction of 24 carcinomata was studied. The incidence of immunoglobulin labelled plasma cells (IgA and IgG) was twice as high in those cases of leukoplakia where dysplasia was present. The number of plasma cells, especially IgA- and IgG-containing plasma cells, decreased significantly with progressive tumor dedifferentiation. The plasma cell response differed before and after radiation with a decrease in IgA- and IgG-containing plasma cells after therapy. In contrast, bleomycin-therapy did not produce distinct changes in the humoral and cellular stromal reaction. In the epithelium, IgA and IgG were localized throughout all epithelial layers in leukoplakias with dysplasia. This finding indicates a leakage of locally synthesized immunoglobulins through an altered oral mucosa. This investigation reveals alterations in the local immune homoeostasis of the oral mucosa in premalignant and malignant lesions which varies with the grade of dysplasia, tumor differentiation and therapy.