Suppressed natural killer cell activity in patients with euthyroid Graves' ophthalmopathy

The purpose of the present study was to determine whether patients with euthyroid Graves' exophthalmopathy have an impaired NK cell function compared to patients with Graves' hyperthyroidism and healthy controls. The NK cell activity measured against K562 target cells was significantly suppressed (p less than 0.01) in patients with euthyroid Graves' ophthalmopathy, whereas the NK cell activity of patients with Graves' hyperthyroidism was not. Although interferon-alpha, interleukin-2 and indomethacin significantly enhanced (p less than 0.01) the NK cell activity in all three groups, none of these agents fully restored the defective NK cell activity in euthyroid Graves' ophthalmopathy. The concentrations in the blood of large granular lymphocytes and CD16 positive cells did not differ between the three groups, furthermore an immunosuppressive serum factor was not detected. The number of effector/target cell conjugates did not differ between patients and controls, whereas the interferon-alpha induced production of a soluble natural killer cytotoxic factor (NKCF) with specificity for NK sensitive target cells was suppressed in patients with Graves' euthyroid ophthalmopathy. We conclude that one of the mechanisms underlying the defective NK cell activity in patients with euthyroid ophthalmopathy may be an impairment of the release of NKCF from the NK cells.     

Impaired release of natural killer cytotoxic factor in patients with primary Sjögren''s syndrome.

The impaired natural killer (NK) cell activity against K562 target cells of patients with primary Sjögren''s syndrome (primary SS) was re-examined in a 2-year follow-up study of 10 patients and 10 normal controls. The ability of blood mononuclear cells (BMNC) to form effector/target cell conjugates and to release NK cytotoxic factor (NKCF) were studied. NK cell activity of the patients was unchanged low (P less than 0.01) compared with the controls. The number of effector/target cell conjugates did not differ between patients and controls, whereas NKCF-release from interferon-stimulated BMNC was significantly (P less than 0.01) reduced in the patients with primary SS and positively correlated to the reduced NK cell activity (r = 0.85, P = 0.0002). The permanently low NK cell activity of patients with primary SS appears therefore, at least in part, to be due to an impaired release of NKCF and not to a defective ability of effector cells to recognize and/or adhere to target cells.     

Depressed natural killer cell activity in acute myocardial infarction.

Natural killer (NK) cell activity against K562 target cells was measured in patients within 24 h of acute myocardial infarction (AMI) and regularly thereafter for 6 weeks. NK cell activity was suppressed on days 1, 3, and 7 (P less than 0.01), day 14 (P less than 0.05) and at 6 weeks (P = 0.05) when compared to controls. Interferon, interleukin 2 and indomethacin enhanced NK cell activity on all days measured, but did not completely restore the defective NK cell activity. Serum from the patients did not suppress the NK cell activity of healthy mononuclear cells. The number of NK cells, identified as large granular lymphocytes (LGL), measured on days 1, 3, and 14 and at 6 weeks was not reduced in comparison to that of controls. Thus, the defective NK cell activity can be characterized as functional.     

Natural killer (NK) cell activity during HIV infection: a decrease in NK activity is observed at the clonal level and is not restored after in vitro long-term culture of NK cells.

NK cell activity is impaired in HIV-infected patients. The mechanisms behind the altered NK functions are not clear, and conflicting data concerning NK and antibody-dependent cellular cytotoxicity (ADCC) activity have been reported. In order to investigate whether this impairment is also observed at the clonal level and whether it is related to a defect at the target cell binding and/or the post-binding level, we evaluated highly purified NK cell lines and cloned NK cells obtained from 22 HIV-infected patients at different stages of disease and compared them with normal controls for their ability to: (i) kill K-562 and U-937 cell lines using a 51Cr release assay; (ii) bind and kill K-562 and U-937 cells at the single cell binding level; (iii) release NK cytotoxic factor (NKCF), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma); (iv) kill anti-IgM preincubated Daudi cell line (ADCC activity). This study with cloned NK cells or NK cell lines from HIV-infected individuals showed: (i) a decrease in their lytic capability against target cell lines; (ii) a low ability to form conjugates with K-562 and U-937 cell lines with respect to controls; (iii) a decreased ability to kill bound target cells; (iv) low levels of released NKCF, TNF-alpha and IFN-gamma after incubation with U-937 cells. Taken together, these findings suggest that the impaired NK cell function during HIV infection is also observed at the clonal level and is related to defects both at the target and post-binding levels. However, the precise mechanisms remain to be determined. The inability to restore normal NK activity after long-term culture in the presence of high levels of recombinant IL-2 is in agreement with the hypothesis of a 'general anergic process' during HIV infection.     

Characterization of the natural killer cell activity in Hashimoto's and Graves' diseases

Natural killer (NK) cell activity and blood mononuclear cell subpopulations were characterized in patients with Hashimoto's thyroiditis ( n = 11), Graves' disease ( n = 20), non-toxic goitre ( n = 10) and in normal controls ( n = 22). NK cell activity against K 562 target cells and the capability of IFN-α, Il-2, and indomethacin to enhance NK cell activity in vitro did not differ significantly between the groups. The percentages of large granular lymphocytes, CD5 +, CD4 +, CD8 + and CD16 + cells were normal in patients with non-toxic goitre, Hashimoto's and Graves' diseases. There was no correlation between NK cell activities and TgAb, MAb and TSAb. Although NK cell activity is suppressed in several autoimmune diseases, NK cell function is normal in patients with autoimmune thyroid disorders.     

Leukocyte migration test for the study of immune reactivity in cases of Graves disease associated with infiltrative ophthalmopathy

The leukocyte migration test was carried out in 26 untreated cases of Graves disease, using crude thyroid extract, human eye muscle antigen and actomyosin as antigens. A significant reduction in the spontaneous (antigen-free) migration values was demonstrable in the cases of Graves disease, compared with the controls. The migration inhibition test gave positive results with the thyroid antigen in the hyperthyroid cases, in opposition to euthyroid ophthalmopathy, where it was found negative. The results were positive with retrobulbar muscle antigen in hyperthyroid and euthyroid infiltrative ophthalmopathy. In advanced cases of infiltrative ophthalmopathy, the results were positive with actomyosin as well.     

Lysis of natural killer-sensitive and -resistant tumor cells by natural killer cytotoxic factors (NKCF)-containing liposomes

The lethal hit stage in NK cell-mediated lysis requires a complex series of events involving the release of NKCF, subsequent binding of these factors to the target cell, and susceptibility of the target cell to lysis by NKCF. Binding of NKCF alone is not sufficient because a number of tumor cells are able to bind NKCF without being lysed, suggesting the need for an additional processing step active on susceptible target cells. In the present study, we show that the interaction with liposome-incorporated NKCF renders NK resistant target cells sensitive to NKCF-mediated lysis. These results suggest that NKCF may mediate their cytotoxic effects through internalization of these factors into the cytosol.     

Role of natural killer cytotoxic factors in the mechanism of target-cell killing by natural killer cells

Studies on the mechanism of cell-mediated cytotoxicity (CMC) have suggested a stimulus-secretion model and implicated a role of soluble cytotoxic mediators. Our studies in the natural killer (NK) system provide several lines of evidence for the involvement of natural killer cytotoxic factors (NKCF) in NK CMC and led to the development of a model for the NK lytic mechanism. This model delineates several interactions between NK cells and targets that are deemed necessary to achieve target-cell lysis. The first stage is the interaction of the effector with the target cell, resulting in contact and adhesion. This is presumably mediated by NK recognition structures and target-cell structures. Following binding, the target cell stimulates the NK cell to release NKCF. This step is functionally distinct from the initial effector-target binding. The trigger mechanism for release of NKCF appears to be dependent on protein kinase C. The released NKCF binds to NKCF binding sites on the target cell followed by processing or internalization and, ultimately, resulting in cell death. This model has been shown to be useful in investigating the mechanism of defective NK activity in certain disease states. Biochemical analysis and comparative studies suggest that NKCF is a distinct molecule from other cytotoxins studied to date. The studies in the NK CMC system supporting a role of cytotoxic mediators also suggest a possible role for cytotoxic factors in other cytotoxic systems. Furthermore, the selective susceptibility to lysis of tumor or infected cells by NKCF suggests a possible role of their effectiveness inin vivo therapy.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. II. Increased Sensitivity to Natural Killer Cytotoxic Factor (NKCF)

Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.     

Identification of subgroups of euthyroid graves's ophthalmopathy

We attempted to determine if euthyroid Graves's ophthalmopathy is a single entity or a heterogeneous group of disorders. Activity of long acting thyroid stimulator protector occurred in 31 of 33 patients with Graves's hyperthyroidism but in only nine of 17 with euthyroid Graves's ophthalmopathy. Of the euthyroid patients, six had protector activity and thyroid non-suppressibility; firm goiters and high titers of thyroid antibodies were the rule in this group. We believe that these patients have three autoimmune diseases: Hashimoto's thyroiditis, Graves's thyroid disease and Graves's ophthalmopathy. Five euthyroid patients had no detectable protector activity or thyroid antibodies and had normal thyroid suppressibility; the thyroid was generally normal in size and consistence. These patients are interpreted as having "isolated" Graves's ophthalmopathy without any autoimmune thyroid disease. The remaining six patients showed dissociation between protector activity and thyroid non-suppressibility and cannot be classified as yet. Euthyroidism in Graves's ophthalmopathy may have more than one cause.     

Increased killer immunoglobulin-like receptor expression and functional defects in natural killer cells in lung cancer

Frequencies of natural killer (NK) cells from patients with non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC) did not differ from healthy controls. A higher proportion of NK cells from NSCLC patients expressed the killer immunoglobulin-like receptor (KIR) CD158b than in controls (P = 0.0004), in the presence or absence of its ligand, HLA-C1. A similar result was obtained for CD158e in the presence of its ligand HLA-Bw4 in NSCLC patients (P = 0.003); this was entirely attributable to the Bw4I group of alleles in the presence of which a fivefold higher percentage of CD158e(+) NK cells was found in NSCLC patients than controls. Proportions of CD158b(+) NK cells declined with advancing disease in NSCLC patients. Expression of NKp46, CD25 and perforin A, and production of interferon-γ following stimulation with interleukin-12 and interleukin-18, were all significantly lower in NK cells from NSCLC patients than in controls. Both NK cell cytotoxicity and granzyme B expression were also reduced in lung cancer patients. Increased inhibitory KIR expression would decrease NK cell cytotoxic function against tumour cells retaining class I HLA expression. Furthermore, the reduced ability to produce interferon-γ would restrict the ability of NK cells to stimulate T-cell responses in patients with lung cancer.     

Effects of X-ray irradiation on natural killer (NK) cell system. II. Increased sensitivity to natural killer cytotoxic factor (NKCF)

Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.     

Effects of X-RAY Irradiation on Natural Killer (NK) Cell System. II. Increased Sensitivity to Natural Killer Cytotoxic Factor (NKCF)

Abstract

Irradiation with low-doses of X-rays of tumor cells elevated their susceptibility to lysis by natural killer (NK) cells in an accompanying paper. Cytotoxicity assays conducted at the single cell level revealed that X-ray irradiation of K562 cells did not affect the number of effector-target conjugates but increased the frequency of dead conjugated target cells. During interaction with K562 cells large granular lymphocytes released a soluble cytotoxic factor (NKCF) that killed the target cells. X-ray irradiation did not affect the NKCF stimulatory ability of K562 cells, while it elevated their sensitivity to the lytic effect of NKCF. In contrast to X-rays, exposure to ultraviolet (UV) radiation of K562 cells did not elevate their NK sensitivity but rather reduced it. Treatment with mitomycin C produced no effect on NK sensitivity. These results indicate that X-ray irradiation elevates the target sensitivity to NKCF, which may be involved in the increased NK sensitivity, and that the X-ray effect may be different from that of UV radiation or DNA synthesis inhibition.     

Increase in peripheral natural killer cell activity in patients with autoimmune thyroid disease.

Changes in the activity and number of natural killer (NK) cells in peripheral blood in patients with autoimmune thyroid disease were examined. NK activity was measured in a 4-hr 51Cr-release assay and the number of NK cells was analyzed with FITC-conjugated monoclonal antibodies by use of an automated flow cytometer. NK activity in patients with untreated Graves' disease (n = 25, 39.7 +/- 13.5%, P less than 0.05) and Hashimoto's thyroiditis (n = 18, 41.0 +/- 14.2%, P less than 0.05) was high compared to the activity in non-pregnant controls (n = 61, 32.6 +/- 15.0%). NK activity in patients with postpartum Graves' thyrotoxicosis (n = 11, 48.6 +/- 18.9%) was markedly increased compared to the activity in non-pregnant controls (P less than 0.01) and in postpartum controls (n = 29, 33.8 +/- 15.2%, P less than 0.05), although the mean ages of each group did not differ significantly. Moreover, NK activities in the thyrotoxic state were significantly higher than those in the euthyroid state in the same patients with postpartum Graves' thyrotoxicosis or with postpartum destructive thyrotoxicosis. The number of CD16 positive cells increased in patients with postpartum Graves' thyrotoxicosis. However the number of CD16 and CD57 positive cells were normal in all other groups of patients. These results indicate that an increase of NK activity is associated with exacerbation of autoimmune thyroid disease both in Hashimoto's thyroiditis and in Graves' disease and suggest that NK cells might have an important role for the control of disease activity in autoimmune thyroid disease.     

Immunoregulatory dysfunctions in type I diabetes: Natural and antibody-dependent cellular cytotoxic activities

Peripheral blood lymphocytes from 13 patients with established insulin-dependent diabetes mellitus (IDDM) and 2 prediabetic patients were examined for natural killer (NK) and antibody-dependent cellular cytotoxic activities (ADCC), lectin-dependent cellular cytotoxicity (LDCC), interferon- and interleukin-2-induced cytotoxicity, and concanavalin A-induced suppressor-cell activities in comparison with age-matched normal controls. IDDM patients demonstrated normal levels of NK and ADCC activities against K562 and antibody-coated SB target cells, respectively, compared to controls. IDDM patients showed normal levels of LDCC activity. Notable deviations from control values were, however, observed with diabetic lymphocytes in the following systems. Interferon-and interleukin-2-induced NK activities were significantly higher with IDDM lymphocytes than with control cells. IDDM lymphocytes precultured with concanavalin A demonstrated lower NK and ADCC activities than control cells and manifested decreased suppressor effects on the NK activity of normal allogeneic lymphocytes. Lymphocytes from one of two prediabetic patients showed increased NK, ADCC, and LDCC activities in comparison to controls. The increased interferon- and interleukin-2-induced enhancement of NK activity and reduced suppressor activity of lymphocytes from IDDM patients may be involved in the pathogenesis of the disease.     

Heterogeneity in the activation requirements of T cells stimulated by phytohaemagglutinin.

Natural killer (NK) activity is inhibited by the contact of peripheral blood lymphocytes with primary monolayer cell cultures of both benign and malignant origin. In this study the effect of interferons (IFNs) on the inhibition has been analysed. Both alpha IFN- and gamma IFN-pretreated peripheral blood lymphocytes are effectively inhibited by monolayer target cells. IFN treatment of lymphocytes does not change cytotoxicity against the inhibitory target cells, although it enhances reactivity against NK-sensitive target cells. Treatment of monolayer cells with interferons significantly reduces their inhibitory capacity. However, diminished inhibition of NK activity by the IFN-treated target cells is not associated with increased lysis, probably due to their decreased sensitivity to natural killer cytotoxic factors (NKCF). In 18.5% of the cases studied, monolayer target cells induced endogenous IFN production in lymphocytes. In these cases no inhibition of the NK activity of the effector cells was seen. According to the results of this paper, IFNs have a dual effect on the NK regulatory system: they enhance the NK activity of the effector cells against NK-sensitive target cells, and they change the NK resistant target cells in a way that makes them less inhibitory to NK activity but simultaneously more resistant to the toxic factors secreted by NK cells.     

Graves’眼病患者血清IL-2、sIL-2R和TGF-β测定的临床意义

目的：探讨Graves’眼病患者血清IL-2、sIL-2R和TGF-β水平的变化、病情进展和病因学的关系。方法：对照组30名和Graves眼病30例患者的血清TGF-β含量均采用放射免疫分析;血清IL-2、sIL-2R均采用酶联免疫吸附试验。结果：30例Graves’眼病患者血清IL-2治疗前水平非常显著低于对照组（P〈0.01）;经免疫抑制剂治疗6个月后水平较治疗前升高非常显著,与对照组比较已无显著性差异（P〉0.05）;sIL-2R含量治疗前非常显著的高于治疗后组和对照组（P〈0.01）;经用上述方案治疗后与对照组比较下降非常显著,但仍存在显著性差异（P〈0.05）;血清TGF-β浓度在治疗前非常显著地高于对照组（P〈0.01）;经治疗后显著下降,但与对照组比较差异仍非常显著（P〈0.01）。结论：Graves’眼病患者血清IL-2、sIL-2R和TGF-β三项血清指标的测定对于了解和认识其发病机理及预估病情有帮助。     

Pathogenesis of the natural killer cell deficiency in AIDS

Deficiency in natural killer (NK) cell activity is a common feature of acquired immune deficiency syndrome (AIDS). This is part of a general immune dysfunction in AIDS and may lead to progression of the disease, since NK cells are known to be involved in protection against tumors and against viral infections. The lack of immunological surveillance by NK cells of the growth of pathogens that activate the HIV-1 tat infectivity gene may also favor progression to AIDS. The pathogenesis of NK cell deficiency in AIDS is not known. Previous studies have shown that NK cells from AIDS patients are able to bind but not to lyse the target cell line K562. This results from an inability to rearrange the cytoskeleton microtubular (MT) system and to release the natural killer cytotoxic factor (NKCF). This report by Maria Caterina Sirianni and colleagues evaluates the possible mechanisms leading to this NK cell deficiency.     

Extraocular muscle autoimmunity and orbital fat inflammation in thyroid-associated ophthalmopathy

The immunological basis for the ophthalmopathy associated with Graves’ hyperthyroidism is both poorly understood and controversial. The mechanism for its link with thyroid autoimmunity is unknown but likely to be due to autoimmunity against some thyroid and orbital tissue-shared antigen, such as the thyroid-stimulating hormone receptor, which is expressed on the orbital pre-adipocyte and extraocular muscle cell, or the putative ‘eye muscle cell membrane antigen’. Chronic upper-eyelid retraction, which sometimes occurs as a dominant feature of ophthalmopathy or as an isolated abnormality, is a common and related orbital disorder. Recent evidence that antibodies targeting the calcium-binding protein calsequestrin are specific and sensitive markers of eye muscle and upper-eyelid muscle damage has highlighted the need for diagnostic antibody tests in ophthalmopathy. In the context of this confusion, this review will address the nature of the autoimmune reactions in thyroid-associated ophthalmopathy, focusing on the eye muscle.     

Cellular immunity and IgE levels in atopic patients

Twenty young adult atopic patients and their matched controls were studied. Spontaneously generated and Con-A-induced suppressor T cell functions as well as Natural Killer (NK) activity against K-562 target cells, measured in a short-time 3H-thymidine uptake, were evaluated. Suppressor T cell activity in the patients was more than 2 SD lower than that found in the controls and there was, contrary to expectation, a direct correlation between suppressor function and serum IgE levels. Atopic patients showed a statistically significant lower NK activity than normal controls when related to a low IL-2 production. Both facts inversely correlated with the concentration of IgE in serum. We concluded that atopic patients' vulnerability to viral infections may be due to defective NK activity. Suppressor T cell function is abnormal in these patients. Both defects could be due to a faulty immunoregulatory helper function.