Increased natural killer cell activity correlates with low or negative expression of the HER-2/neu oncogene in patients with breast cancer

Application of an improved flow cytometry-based NK cell activity assay in adult hemophagocytic lymphohistiocytosis

Low or absent natural killer (NK) cell activity is included as one of the HLH-2004 diagnostic criteria. To improve the diagnosis of HLH, we aimed to establish a rapid and reliable NK cell activity assay that avoids the use of radioactivity. The K562 cell line, as standard NK target cells, was engineered to stably express enhanced green fluorescent protein (EGFP), which can be quantified by flow cytometry. The EGFP-flow cytometry method for measuring NK cell activity was improved by double staining of early and late apoptotic target cells. Whole-blood samples from healthy volunteers were assessed with this method, which demonstrated that optimal conditions were effector-target ratio of 10:1 and incubation time of 4 h. This method was further evaluated for samples from 113 HLH patients and 64 healthy volunteers. Mean NK cell activity in either primary or secondary HLH patients was significantly lower (P < 0.001) than in healthy individuals (20.23 ± 4.12%). Furthermore, primary HLH patients (10.76 ± 2.54%) exhibited even lower (P < 0.001) NK cell activity compared with secondary HLH patients (15.01 ± 3.62%). We have optimized and implemented this method in clinically relevant samples.

Evaluation of NK cell function by flowcytometric measurement and impedance based assay using real-time cell electronic sensing system

Although real-time cell electronic sensing (RT-CES) system-based natural killer (NK) cytotoxicity has been introduced, it has not been evaluated using human blood samples. In present study, we measured flowcytometry based assay (FCA) and RT-CES based NK cytotoxicity and analyzed degranulation activity (CD107a) and cytokine production. In 98 healthy individuals, FCA with peripheral blood mononuclear cells (PBMCs) at effector to target (E/T) ratio of 32 revealed 46.5 ± 2.6% cytolysis of K562 cells, and 23.5 ± 1.1% of NK cells showed increased degranulation. In RT-CES system, adherent NIH3T3 target cells were resistant to basal killing by PBMC or NK cells. NK cell activation by adding IL-2 demonstrated real-time dynamic killing activity, and lymphokine-activated PBMC (E/T ratio of 32) from 15 individuals showed 59.1 ± 6.2% cytotoxicity results after 4 hours incubation in RT-CES system. However, there was no significant correlation between FCA and RT-CES cytotoxicity. After K562 target cell stimulation, PBMC produced profound proinflammatory and immunoregulatory cytokines/chemokines including IL-2, IL-8, IL-10, MIP-1 α β , IFN- γ , and TNF- α , and cytokine/chemokine secretion was related to flowcytometry-based NK cytotoxicity. These data suggest that RT-CES and FCA differ in sensitivity, applicability and providing information, and further investigations are necessary in variable clinical conditions.

Establishment of a reference interval for natural killer cell activity through flow cytometry and its clinical application in the diagnosis of hemophagocytic lymphohistiocytosis

Recently, the Histiocyte Society revised the diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH) to include low or absent natural killer (NK) cell activity, according to local laboratory reference. The aim of this study was to establish reference interval for functional NK-cell activity in 63 healthy Korean individuals using a flow-cytometric assay. We used peripheral blood mononuclear cells (PBMCs) as effector cells and Fluorescein isothiocyanate-labeled K562 cells as target cells. NK-cell activity was calculated using the following equation: NK-cell activity (%) = (test lysis - spontaneous lysis) x 100/(maximum lysis - spontaneous lysis). NK-cell activity was analyzed in 13 known HLH patients and 16 suspected non-HLH patients using a flow-cytometric assay. The mean (+/-SD) cytotoxicity of PBMCs from healthy individuals was 20.9 +/- 5.3% and the reference interval was 11.8-31.9%. The mean NK-cell activity of HLH patients (8.3 +/- 8.9%) was significantly lower (P = 0.001) than that of non-HLH patients (20.1 +/- 7.8%). The sequential changes in NK-cell activity in the HLH group corresponded to clinical and laboratory findings following treatment. We successfully developed a functional NK-cell activity test for use in the clinical laboratory and obtained a reference interval of NK-cell activity from healthy donors. This assay, and associated reference interval, was used to analyze 30 clinically relevant specimens and the results were shown to be well correlated.

Group interventions for patients with cancer and HIV disease: Part II. Effects on immune, endocrine, and disease outcomes at different phases of illness

There has been great interest in the potential impact of group interventions on medical outcomes. This article reviews the effects of professionally-led groups on immune activity, neuroendocrine function, and survival among patients with cancer or HIV disease. We examine findings concerning different types of group services at different phases of illness. Results are mixed, but the most prominent changes in immune and endocrine activity were associated with structured group interventions for patients with early-stage disease. These findings offer provocative illustrations of relevant mind-body interactions, but their clinical importance has yet to be demonstrated empirically. Group interventions have not been tied consistently to improved survival rates for patients with advanced cancer; few studies as yet have focused on survival outcomes among patients with early-stage cancer or HIV disease.

Stress, coping, and immune function in breast cancer

Research has found suggestive links between emotional distress and immune and neuroendocrine measures in cancer patients. Furthermore, several studies have reported that participation in psychological support groups is associated with better health outcomes for cancer patients. However, controversy exists surrounding these findings, and the mechanisms behind such effects are unclear. This article integrates current evidence from several lines of research concerning the relations among coping, psychological adjustment, cortisol and immune function, and disease progression in breast cancer patients. A biopsychosocial model is evaluated in which coping and psychological adjustment are associated with alterations in cortisol levels, immune function, and potential long-term medical outcomes in breast cancer patients. Although strong evidence suggests that coping and psychosocial intervention can improve psychological outcomes for breast cancer patients, potential effects on physiological outcomes remain speculative.

Association between immunity and prognostic factors in early stage breast cancer patients before adjuvant treatment

OBJECTIVE

The association of known prognostic factors with immune cell counts and beta2-microglobulin and soluble IL-2 receptor (sIL-2r) serum levels as markers of activation of the immune system was investigated in breast cancer.

METHODS

Two hundred thirty five operated stage I and II breast cancer patients to receive adjuvant treatment in IBSCG trials were assessed in a cross-sectional study immediately before the first treatment. Leukocytes, lymphocytes and lymphocyte subset counts, beta2-microglobulin and sIL-2r serum levels were assessed as immunological parameters. Prognostic factors were tumor load, receptor status, patient characteristics, and contextual factors of the immune assessment (such as time of the day, time since surgery, type of surgery, concomitant medication, co-morbidity).

RESULTS

In an operated early stage breast cancer patient population, tumor load was not associated with immune cell counts, beta2-microglobulin, or sIL-2r before adjuvant treatment. There was a pattern of association of prognostically favorable factors such as estrogen receptor (ER) positive tumor and older age with higher NK cell counts or with beta2-microglobulin or sIL-2r. In addition, immune cell counts and the markers of activation of the immune system were affected by several contextual factors, such as diurnal variability, time since surgery, type of surgery, and the intake of concomitant medication.

CONCLUSIONS

The association of NK cell counts and beta2-microglobulin or sIL-2r serum levels with prognostically favorable factors such as ER positive tumor and older age supports the assumption that the immune system plays a role in the course of early breast cancer. The exact nature of this role requires further study.

Chronic and acute stress as predictors of relapse in primary breast cancer patients

In this paper we present data on predictors of early relapse (at three and a half years post-surgery) in 44 patients with primary breast carcinoma. We expected that the degree to which receiving the diagnosis of malignancy would act as an acute stressor would allow a prediction of early relapse. Acute stress is measured by means of changes in psychological, neurochemical and immunological indicators of stress before and after the communication of the diagnosis. The results indicate that the assumption does not hold. Chronic stress, however, appears to be a strong predictor of early relapse. The measure of chronic stress is based on a self-report questionnaire of health complaints in the year before the diagnosis of breast cancer.

Immunologic approaches to inhibiting cell-surface-residing oncoproteins in human tumors

The erbB family of receptor tyrosine kinases are growth factor receptors that are overexpressed or mutated in a large variety of human cancers. Studies of erbB-mediated signal transduction will lead to an understanding of the role played by this family of receptors in normal and transformed cells. In this article, we discuss the contemporary understanding of the structure and function of these receptors, and how these features might be exploited in immunologic strategies of receptor-based growth inhibition. The first part of this article details the structure of erbB receptors as it relates to the process of transformation of cells and the malignant phenotype in human tumors. In the second part of this article, we discuss immunologic approaches to therapy for cancers in which surface-residing erbB receptors are overexpressed or mutated, with an emphasis on studies targeting the p185neu/c-erbB2 oncoprotein. The potential for antireceptor immunity and the evolution of small molecules for receptor-based immunotherapy are discussed. These studies provide a basis for the application of receptor-based strategies of growth inhibition in erbB-expressing human cancers.

HER-2/neu protein: a target for antigen-specific immunotherapy of human cancer

The HER-2/neu oncogenic protein is a tumor antigen. Some patients with cancer have a preexistent immune response directed against the HER-2/neu protein. Effective cancer vaccines targeting HER-2/neu will be able to boost this immunity to potentially therapeutic levels. In addition, HER-2/neu-directed monoclonal antibody therapy has been effective in eradicating malignancy in animal models and has shown benefit in the treatment of human HER-2/neu-overexpressing cancers. This review outlines studies that define HER-2/neu-specific immunity in patients with cancer and overviews the current vaccine strategies for generating or augmenting neu-specific immunity. The potential problems associated with eliciting HER-2/neu-specific immunity are addressed, including the question of precipitating autoimmune toxicity against this "self" -protein and the mechanisms of immunological escape that may play a role in preventing effective function of the HER-2/neu-specific immune response. Finally, antibody-based HER-2/neu-directed therapies are overviewed. HER-2/neu is a prototype antigen for groups investigating innovative modifications of monoclonal antibody technology, and cutting edge therapies targeting this antigen are being contemplated for clinical use in the treatment of human malignancy. Immune-based treatments designed to target the HER-2/neu oncogenic protein will soon give the clinical oncologist new therapeutic weapons, directed against a biologically relevant tumor-related protein, with which to fight cancer.

Determination of natural killer cell function by flow cytometry

Natural killer cells (NK cells) are a subset of peripheral blood lymphocytes that mediate non-major histocompatibility complex-restricted cytotoxicity of foreign target cells. The "gold standard" assay for NK cell activity has been the chromium release assay. This method is not easily performed in the clinical laboratory because of difficulties with disposal of radioactive and hazardous materials, short reagent half-lives, expense, and difficulties with assay standardization. We describe a flow cytometric assay for the clinical measurement of NK cell activity. This study compared the chromium release assay and the flow cytometric assay by using clinically relevant specimens. There were no significant differences between the two assays in the measurement of lytic activity for 17 peripheral blood specimens or in reproducibility in repeated samplings of healthy individuals. We also established a normal range of values for NK activity in healthy adults and identified a small cluster of individuals who have exceptionally high or low levels of NK activity. The flow cytometric assay was validated by testing specimens from subjects expected to have abnormally low levels of NK activity (pregnant women) and specimens from healthy individuals in whom the activity of NK cells was enhanced by exposure to interleukin-2 or alpha interferon. Treatment with these agents was associated with a significant increase in NK activity. These results confirm and extend those of others, showing that the flow cytometric assay is a viable alternative to the chromium release assay for measuring NK cell activity.

Outgrowth of BT-474 human breast cancer cells in immune-deficient mice: a new in vivo model for hormone-dependent breast cancer

The effect of co-inoculation of basement membrane matrix, Matrigel and two human breast cancer cell lines, BT-474 and SK-BR-3, was tested in immune-deficient mice. Both cell lines strongly overexpress c-ErbB-2 protein, whereas only BT-474 is reported to be oestrogen receptor positive. Co-inoculation of Matrigel and BT-474 cells but not of Matrigel and SK-BR-3 cells resulted in tumour formation in bg-nu-xid mice. Oestrogen supplementation greatly enhanced tumorigenicity, but did not seem to be an absolute requirement. In vivo, BT-474 cells grow as a poorly differentiated adenocarcinoma with a doubling time of 9.4 +/- 1.1 days after inoculation into the neck region. A high proliferative activity appears to be compensated by a relatively high rate of cell loss, as BT-474 tumours contain many cells with the typical morphology of apoptotic cell death. Wild-type p53, known to participate in the induction of apoptosis, is absent from the tumours, whereas Bcl-2, known to inhibit apoptosis, is expressed at intermediate levels. BT-474 tumours tend to metastasise to the regional lymph nodes and are capable of forming micrometastatic lesions in the lung. Flow cytometrical analysis of DNA ploidy demonstrated no change in tumours compared with the cell line. Immunohistochemical and flow cytometrical detection of a number of hormone and growth factor receptors, transcription factors, cell adhesion molecules and proteins involved in proliferation and cell death demonstrated no major changes in ploidy and phenotype of tumours compared with the cell line. High expression of the cell-surface molecules c-ErbB-2 and episialin make it a potentially useful model for research in immune therapy.

Pre-eclampsia, autoimmune diseases and breast cancer etiology

Previous hypotheses concerning the negative association between pre-eclampsia (or pregnancy-induced hypertension) and breast cancer risk have focused on hormone-related factors. A hypothesis is presented that certain non-specific cellular immune responses could be involved in this association and in the negative association between autoimmune diseases (i.e., systemic lupus erythematosus and rheumatoid arthritis) and certain cancers. Future directions for epidemiological and laboratory research suggested by this hypothesis are discussed.