Antitumor immunity to oral cancer was assessed in 46 patients suffering from squamous cell carcinoma of the oral cavity using a leucocyte adherence inhibition assay (LAI). The response shown by the leucocytes of oral cancer patients to the oral cancer antigen was compared to that shown by the leucocytes from 10 normal age- and sex-matched healthy controls and 43 patients suffering from other types of cancers. Seventy-six percent of the oral cancer patients showed a high degree of leucocyte adherence inhibition in the presence of the antigen. The specificity of this test was further assessed using combinations of the leucocytes from oral cancer patients with extracts from seven cancers occurring at various other sites and extracts of normal oral tissue. The test was highly specific and the leucocytes of oral cancer patients showed significant inhibition only in the presence of oral cancer extract. The inhibition was between 0 and 30% with most other cancer extracts except in the case of extract from cancer of the cervix, where 410 patients showed above 30% inhibition. Specific blocking of the LAI response was observed on addition of sera from oral cancer patients to leucocyte-antigen mixtures from oral cancer patients. This effect was not observed on addition of these sera to specific leucocyte-antigen mixtures from other cancer patients. These observations point towards the usefulness of this test in monitoring antitumor immunity in oral cancer patients.
B. Prabha and Dr. Damodaran Vasudevan, “Leucocyte adherence inhibition assay (LAI) in cancer of the oral cavity”, European Journal of Cancer and Clinical Oncology, vol. 20, pp. 891–897, 1984.