CELLULAR IMMUNE DEFECT CAUSED BY POSTSURGICAL RADIATION-THERAPY IN PATIENTS WITH HEAD AND NECK-CANCER

The effects of locoregional postoperative radiation therapy (60 Gy on average) on cellular immunity were investigated in 11 patients with sq uamocellular carcinomas of the oral cavity, pharynx, or larynx, During radiation treatment, the total lymphocyte counts, CD8(+) T-lymphocyte count, and especially CD4(+) T-lymphocyte count decreased significant ly. The mean CD4+ T-lymphocyte counts dropped from an average of 739/m u l to 183/mu l (p <0.001), and the CD4(+)/CD8(+) quotient also decrea sed significantly. Not only the lymphocyte counts but also the in vitr o lymphocyte stimulation responses to several mitogens decreased, with reductions averaging 10% to 50% of normal responses by the end of rad iation therapy. Within 3 to 4 weeks after radiation therapy, the CD4() T-lymphocyte counts and the in vitro lymphocyte stimulation response s showed a tendency toward normalization. This study shows that postop erative locoregional radiation therapy in patients with head and neck cancer induces a severe generalized impairment of cellular immunity.