A study of the effect of radiation therapy in head and neck region on phagocytic activity of polymorphonuclear leukocytes

To determine the phagocytic activity of polymorphonuclear leukocytes in head and neck carcinoma before and after radiation therapy, the image processing system was applied to phagocytic plaque assay. Variable coefficients of the present phagocytic plaque assay were 0.15 for plaque count and 0.05 for phagocytic area, allowing the quantification of the present assay. Patients with head and neck carcinoma had a significantly increased phagocytic activity. The phagocytic activity did not correlate with either clinical stage or the differentiation of squamous cell carcinoma. The phagocytic area not treated with blood plasma was significantly greater in carcinoma of the tongue and gingiva than carcinoma of the oral floor. When treated with blood plasma, it was significantly increased in carcinoma of the gingiva as compared with carcinoma of the oral floor. Plaque count remained unchanged throughout the study period. Phagocytic area also remained unchanged up to one month after radiation therapy; and at 4 to 12 months it returned to normal. There was no correlation between the phagocytic activity and blood cell count. When external irradiation combined with surgery was given, the phagocytic activity of polymorphonuclear leukocytes did not change up to one month after the treatment. However, interstitial irradiation tended to cause immediate recovery of the phagocytic activity. At 4 to 12 months after irradiation, the phagocytic activity returned to normal, regardless of irradiation modes. These results suggest that irradiation may not exert direct influence on the phagocytic activity of polymorphonuclear leukocytes, but may reflect the secondary change associated with tumor disappearance, i.e. the recovery of phagocytic activity. (N.K.) 68 refs