Population of K-lymphocytes in various kinds of thyroid disease

We have measured the population of Killer (K) lymphocytes in the peripheral blood of 108 patients with various kinds of thyroid disease. In the patients with Hashimoto's thyroiditis and Graves' disease, the relative and absolute numbers of K-lymphocytes were significantly lower than those seen in healthy controls (p less than 0.001), and the longer the duration of medication, the lower the K-lymphocyte population. However, there was no apparent correlation between the serum titers of thyroid autoantibodies and the K-lymphocyte population. In the patients with malignant and benign thyroid tumors, the relative and absolute numbers of K-lymphocytes significantly decreased when compared with those of controls (p less than 0.001), the decrease was more prominent after surgical operation than before operation. A prominent decrease in the K-lymphocyte population was evoked to maximum 2 to 4 weeks after surgical operation. The patients with both malignant and benign tumors having abundant lymphocytic infiltration in their surgical specimens generally revealed a lower K-lymphocyte population than those having no lymphocytic infiltration.