Peripheral K Cells in Graves’disease and Hashimoto's Thyroiditis in Relation to Circulating Immune Complexes

Abstract

A plaque assay was employed to quantify the number of peripheral K cells in autoimmune thyroid diseases. The percentages of peripheral K cells determined were 3.1 +/- 2.2% and 3.3 +/- 1.3% (mean +/- SD) in forty-one patients with Graves' disease and twenty-two patients with Hashimoto's thyroiditis, respectively, which were significantly lower than 5.3 +/- 2.5% in 22 normal subjects. Circulating immune complexes (ICs) were measured by three different methods. The positivity of these ICs was investigated in relation to the level of peripheral K cells. The percentage of peripheral K cells in the patients positive for ICs was found to be lower than that in the patients negative for any ICs. Moreover, it was observed that the number of detectable K cells from a normal subject was significantly decreased by incubating the K cells with sera of patients positive for ICs. These results suggest that the decrease of peripheral K cells in the patients with autoimmune thyroid diseases may be due to saturation of K cell Fc receptors by binding ICs.

Immune Mechanisms In Graves' Disease

“…NK cell numbers returned to Spring, 1985 GRAVES' DISEASE 207 normal in euthyroid Graves' disease patients and in patients in remission. Endo et al (398) also used a plaque assay to note decreased NK cell numbers in the peripheral blood of Graves' disease patients with active disease (Graves': 3.2 ± 1.3%: 73 ± 38 cells/ml vs. normals 5.3 ± 2.6%; 128 ± 51 cells/ml).…”

“…Although the precise role of natural killer cells, ADCC and lymphocytotoxicity in the mediation of immune injury in Graves' disease are unknown, we shall review these systems and their potential relationship to Graves' disease as they have been suggested to be important in autoimmune thyroid disease (149,150,(397)(398)(399)(400)(401)(402)(403)(404)(405). NK cells are a subset of T cells which appear to be responsible for immune surveillance (406).…”

“…The customary assay system uses serum, peripheral white cells (which contain killer cells) and appropriate radiolabeled target cells. Several studies have examined NK cells and ADCC activity in autoimmune thyroiditis (149,(397)(398)(399)(400)(401)(402)(403)(404)(405) (399) employed a plaque-forming system to identify only 2.6 ± 1.5% (mean ± SD) NK cells in the peripheral blood of Graves' disease patients compared to 4.7 ± 1.4% in normals. NK cell numbers returned to Spring, 1985 GRAVES' DISEASE 207 normal in euthyroid Graves' disease patients and in patients in remission.…”

Reduced intrathyroidal K-cell activity in Graves' disease

“…Amino et al (1982), who used a plaque-forming cell technique, could demonstrate reduced counts of K-cells in thyrotoxic but nor¬ mal levels in euthyroid patients. Endo et al (1983) and Yagi et al (1983), applying a similar tech¬ nique, found reduced K-cell counts in Graves' disease irrespectively of the metabolic status, whereas the latter group also detected a decreased K-cell population in malignant and benign tu¬ mours.…”

Increase in Peripheral Large Granular Lymphocytes in Postpartum Autoimmune Thyroiditis.

“…As for induction of destructive thyrotoxicosis in AITD, it is also necessary to consider the participation of other factors, such as the change in the thyroid gland itself as the target, anti-thyroid autoantibodies with which K cells cooperate (Calder et al, 1973;Amino, 1986) and blocking factors acting against NK and K cells like immune complexes (Barkas et al, 1976;Ohtaki et al, 1981;Endo et al, 1983). Under certain conditions produced by these factors, the increase in LGL may not always be accompanied with destructive thyrotoxicosis.…”