Natural killer activity and serum immunosuppressive acidic protein levels in esophageal and gastric cancers

Assessment of NK Cell Activity Based on NK Cell-Specific Receptor Synergy in Peripheral Blood Mononuclear Cells and Whole Blood

Natural killer (NK) cells are cytotoxic innate lymphocytes endowed with a unique ability to kill a broad spectrum of cancer and virus-infected cells. Given their key contribution to diverse diseases, the measurement of NK cell activity (NKA) has been used to estimate disease prognosis or the effect of therapeutic treatment. Currently, NKA assays are primarily based on cumbersome procedures related to careful labeling and handling of target cells and/or NK cells, and they require a rapid isolation of peripheral blood mononuclear cells (PBMCs) which often necessitates a large amount of blood. Here, we developed an ELISA-based whole blood (WB) NKA assay involving engineered target cells (P815-ULBP1+CD48) providing defined and synergistic stimulation for NK cells via NKG2D and 2B4. WB collected from healthy donors (HDs) and patients with multiple myeloma (MM) was stimulated with P815-ULBP1+CD48 cells combined with IL-2. Thereafter, it utilized the serum concentrations of granzyme B and IFN-γ originating in NK cells as independent and complementary indicators of NKA. This WB NKA assay demonstrated that MM patients exhibit a significantly lower NKA than HDs following stimulation with P815-ULBP1+CD48 cells and had a good correlation with the commonly used flow cytometry-based PBMC NKA assay. Moreover, the use of P815-ULBP1+CD48 cells in relation to assessing the levels of NKG2D and 2B4 receptors on NK cells facilitated the mechanistic study and led to the identification of TGF-β1 as a potential mediator of compromised NKA in MM. Thus, our proposed WB NKA assay facilitates the reliable measurement of NKA and holds promise for further development as both a clinical and research tool.

Progressive Impairment of NK Cell Cytotoxic Degranulation Is Associated With TGF-β1 Deregulation and Disease Progression in Pancreatic Cancer

Natural killer (NK) cells are key effectors in cancer immunosurveillance and can be used as a prognostic biomarker in diverse cancers. Nonetheless, the role of NK cells in pancreatic cancer (PC) remains elusive, given conflicting data on their association with disease prognosis. In this study, using conventional K562 target cells and complementary engineered target cells providing defined and synergistic stimulation for NK cell activation, a correlation between impaired NK cell cytotoxic degranulation and PC progression was determined. Peripheral blood mononuclear cells (PBMCs) from 31 patients with newly diagnosed PC, 24 patients with non-malignant tumors, and 37 healthy controls were analyzed by flow cytometry. The frequency, phenotype, and effector functions of the NK cells were evaluated, and correlations between NK cell functions and disease stage and prognosis were analyzed. The results demonstrated that effector functions, but not frequency, of NK cells was progressively decreased on a per-cell basis during PC progression. Impaired cytotoxic degranulation, but not IFN-γ production, was associated with clinical features indicating disease progression, such as high serum CA19-9 and high-grade tumors. Significantly, this impairment correlated with cancer recurrence and mortality in a prospective analysis. Furthermore, the impaired cytotoxic degranulation was unrelated to NKG2D downregulation but was associated with increased circulating and tumor-associated TGF-β1 expression. Thus, NK cell cytotoxic activity was associated with PC progression and may be a favorable biomarker with predictive and prognostic value in PC.

Immunosuppressive Factors: Role in Cancer Development and Progression

The concept of the immunological surveillance against neoplastic cells was initially proposed by Erlich in 1909 and later elaborated by Burnet. This hypothesis states that the normal function of the immune system, in particular the cell-mediated immunity, is to recognize and destroy the transformed and proliferating tumor cells. The role of cell-mediated immunity during the first steps of tumorigenesis remains controversial. However, there is certain evidence about its importance in the progression and dissemination of cancer. The frequent immunosuppressed condition of cancer patients at tumor relapse or recurrence of secondary tumors is a clinical sign supporting this hypothesis, and many studies have demonstrated a defective immune response in patients diagnosed with advanced cancer. Several mechanisms of escape from the immune surveillance have been described, including the immunoselection of tumor antigen-negative variants, the downregulation of MHC class I expression, suppressive T cells, and the elaboration of immunosuppressive cytokines and other factors. Because of the technical difficulty of isolating the very small amounts from culture supernatants or body fluids, only a few of these substances have been characterized and studied with respect to their biological activity: transforming growth factor-β (TGF-β), the protein p15E, interleukin 10 (IL-10), prostaglandin E2 (PGE2), mucins, suppressive E-receptor (SER), immunosuppressive acidic protein (IAP), and adhesion molecules. The possibility of monitoring cancer patients by testing biochemical factors related to cancer growth led to a proposal to measure a number of these factors as tumor markers. Some of them, e.g mucins, enjoy the consensus of the oncologic community, as for some indications they can help the clinician in the management of cancer patients. Except for the class of mucins, the other above-mentioned immunosuppressive factors have not found any clinical application in the laboratory routine because the information deriving from their measurement, although of speculative and scientific interest, has limited clinical value at present. Nevertheless, even if they have no impact on patient management, these substances do have a potential role to play in the study of cancer patients, and should be taken into account when developing new therapeutic strategies.

Correlation Between Natural Killer Cell Activity and Systemic Inflammatory Markers for Heterogeneous Cancer Patients Treated With Wheel Balance Cancer Therapy

Background and Objective: Natural killer (NK) cells are known to have an effect on the prevention of tumorigenesis for the initial cancer, as well as the metastatic cancer. For the past several years, the relationship between cancer and inflammation has been actively studied in preclinical and clinical settings, but there are no reports on alterations in and correlation for NK cell activity (NKA) and systemic inflammatory markers. Accordingly, this study aimed to measure correlation between NKA and the levels of other systemic inflammatory markers in patients with gastric, breast, and pancreatic cancer who received Wheel Balance Cancer Therapy (WBCT). Methods: Forty-two electronic charts of patients with gastric, breast, and pancreatic cancer treated with WBCT from February 1, 2015 to September 30, 2015, were reviewed retrospectively. These charts were statistically analyzed, looking for alterations of and correlation for NKA and the expressions of systemic inflammatory markers. Results: Patients with a NKA of under 300 pg/mL at admission showed significantly higher erythrocyte sedimentation rate (ESR) and neutrophil-to-lymphocyte ratio (NLR) values and decreasing NLR values due to WBCT than patients with an NKA greater than 300 pg/mL. As a result of the correlation analysis between NKA and the levels of the systemic inflammatory markers, NKA showed significant negative correlation with NLR, ESR, and fibrinogen values. Conclusions: Negative correlation was identified between NKA and NLR, NKA and ESR, and NKA and fibrinogen in patients with heterogeneous cancer patients.

Molecular checkpoints controlling natural killer cell activation and their modulation for cancer immunotherapy

Natural killer (NK) cells have gained considerable attention as promising therapeutic tools for cancer therapy due to their innate selectivity against cancer cells over normal healthy cells. With an array of receptors evolved to sense cellular alterations, NK cells provide early protection against cancer cells by producing cytokines and chemokines and exerting direct cytolytic activity. These effector functions are governed by signals transmitted through multiple receptor–ligand interactions but are not achieved by engaging a single activating receptor on resting NK cells. Rather, they require the co-engagement of different activating receptors that use distinct signaling modules, due to a cell-intrinsic inhibition mechanism. The redundancy of synergizing receptors and the inhibition of NK cell function by a single class of inhibitory receptor suggest the presence of common checkpoints to control NK cell activation through different receptors. These molecular checkpoints would be therapeutically targeted to harness the power of NK cells against diverse cancer cells that express heterogeneous ligands for NK cell receptors. Recent advances in understanding the activation of NK cells have revealed promising candidates in this category. Targeting such molecular checkpoints will facilitate NK cell activation by lowering activation thresholds, thereby providing therapeutic strategies that optimize NK cell reactivity against cancer.

NK cell function triggered by multiple activating receptors is negatively regulated by glycogen synthase kinase-3β

Activation of NK cells is triggered by combined signals from multiple activating receptors that belong to different families. Several NK cell activating receptors have been identified, but their role in the regulation of effector functions is primarily understood in the context of their individual engagement. Therefore, little is known about the signaling pathways broadly implicated by the multiple NK cell activation cues. Here we provide evidence pointing to glycogen synthase kinase (GSK)-3β as a negative regulator of multiple NK cell activating signals. Using an activation model that combines NKG2D and 2B4 and tests different signaling molecules, we found that GSK-3 undergoes inhibitory phosphorylation at regulatory serine residues by the engagement of NKG2D and 2B4, either individually or in combination. The extent of such phosphorylation was closely correlated with the degree of NK cell activation. NK cell functions, such as cytokine production and cytotoxicity, were consistently enhanced by the knockdown of GSK-3β or its inhibition with different pharmacological inhibitors, whereas inhibition of the GSK-3α isoform had no effect. In addition, NK cell function was augmented by the overexpression of a catalytically inactive form of GSK-3β. Importantly, the regulation of NK cell function by GSK-3β was common to diverse activating receptors that signal through both ITAM and non-ITAM pathways. Thus, our results suggest that GSK-3β negatively regulates NK cell activation and that modulation of GSK-3β function could be used to enhance NK cell activation.

Increased apoptosis and elevated Fas expression in circulating natural killer cells in gastric cancer patients

BACKGROUND

Immune cells undergo extensive apoptosis in patients with cancer, which may be related to immune evasion by cancerous cells. The present study was designed to investigate the relationship between natural killer (NK) cell apoptosis and Fas expression in gastric cancer patients.

METHODS

NK cell apoptosis and Fas expression were evaluated by multicolor flow cytometry. Soluble Fas ligand (sFasL) was quantitated by enzyme-linked immunosorbent assay.

RESULTS

The frequency of apoptotic NK cells in gastric cancer patients was significantly higher than in normal controls (p = 0.0016). Moreover, their frequency was related to the progression of gastric cancer. Fas-positive NK cells were significantly more common in gastric cancer patients compared with normal controls (p = 0.034). Furthermore, Fas expression was closely related to the frequency of NK cell apoptosis (r = 0.6, p < 0.0001). The frequency of tumor-infiltrating NK cell apoptosis was significantly higher than that of circulating NK cell apoptosis (p = 0.035). Furthermore, Fas-positive NK cells in gastric cancer tissues occurred significantly more often than in peripheral blood (p = 0.029). FasL concentration in gastric cancer patients was lower than that in normal controls, and the difference tended to be significant (p = 0.057). Apoptotic circulating NK cells significantly decreased after surgery compared to before surgery (p = 0.023). Furthermore, Fas expression on circulating NK cells also significantly decreased after surgery compared with before surgery (p = 0.021).

CONCLUSIONS

Upregulation of Fas expression on NK cells is related to increased apoptosis of circulating NK cells in gastric cancer patients.

Intracellular poly(I:C) initiated gastric adenocarcinoma cell apoptosis and subsequently ameliorated NK cell functions

Natural killer (NK) cells are granular lymphocytic cells that exert essential functions in viral infection defense and tumor immune surveillance. However, the functions of NK cells were impaired in cancer patients. Polycytidylic acid [poly(I:C)] has been used as an immune adjuvant to improve innate and adaptive immune responses. In this study, intracellular poly(I:C) could trigger gastric adenocarcinoma cells apoptosis quickly. Meanwhile, the sensitivity of poly(I:C)-treated gastric adenocarcinoma cells to NK cell cytolysis was increased, concomitant with the elevated expression of MICA/B and Fas. Furthermore, the cytolytic activity of NK cells against tumor cells was augmented significantly by the supernatant from poly(I:C)-transfected tumor cells compared with NK cells treated by the supernatant from untreated tumor cells, as well as the proliferation and migration abilities of NK cells. In this process, the activating receptors and cytolysis-associated molecules of NK cells were up-regulated. Further investigation showed that type I interferon (IFN) produced by poly(I:C)-transfected gastric adenocarcinoma cells played an important role in this process. Our findings demonstrated that intracellular poly(I:C) not only triggered gastric adenocarcinoma cell apoptosis, but also enhanced NK responses via inducing type I IFN production by gastric adenocarcinoma cells. These functions make poly(I:C) a promising therapeutic medicine for gastric adenocarcinoma.

Decreased NKG2D expression on NK cells correlates with impaired NK cell function in patients with gastric cancer

BACKGROUND

Although malignant diseases are known to be associated with immune suppression, the detailed mechanisms involved are still unknown. NKG2D is an activating cell surface receptor expressed by natural killer (NK) cells and CD8+ T cells, and the engagement of NKG2D is extremely important for NK cell activation. Although decreased NKG2D expression on NK cells is closely related to immune evasion by some cancers, the immunopathological importance of this phenomenon in gastric cancer patients remains unclear.

METHODS

NKG2D expression on NK cells was determined, using multicolor flow cytometry, to investigate the mechanisms responsible for immune evasion in gastric cancer patients.

RESULTS

NKG2D expression on NK cells from gastric cancer patients was significantly lower than that in healthy controls. Also, NKG2D expression in advanced gastric cancer was significantly lower than that in early gastric cancer. NK cells from patients with lymph node metastasis expressed significantly lower levels of NKG2D than the NK cells from those without lymph node metastasis, and NKG2D expression on NK cells in gastric cancer tissue was significantly lower than that of circulating NK cells. NKG2D expression on NK cells obtained from cancer patients was restored after 48 h in culture with RPMI containing 10% AB serum. Furthermore, NKG2D expression on NK cells obtained after surgery was significantly higher than that before surgery.

CONCLUSIONS

Decreased NKG2D expression on NK cells may be one of the key mechanisms responsible for NK cell dysfunction in gastric cancer.

Serum immunosuppressive acidic protein reflects systemic deterioration of colorectal cancer patient condition

AIMS

Immunosuppressive acidic protein (IAP) is a potent biological marker for immunological surveillance in patients with malignant tumors. This study aimed to investigate the significance of serum IAP as an index of disease status, clinicopathological findings and prognosis in colorectal cancer.

METHODS

A total of 101 patients with colorectal cancer and 80 normal volunteers were included in this retrospective trial. Preoperative serum IAP was assayed using a commercially available enzyme-linked immunosorbent assay kit.

RESULTS

The serum IAP level in the patients, which was not associated with clinicopathological features except for tumor size, was significantly higher than that in controls. The serum IAP level was closely correlated with percent body weight loss, serum albumin and cholinesterase, and percentage of circulating lymphocytes reflecting the host's nutritional and immunological conditions. Interestingly, these parameters were not associated with factors reflecting disease progression except for tumor size. The prognosis of patients with higher IAP levels was significantly worse than that of patients with lower IAP levels. Furthermore, an elevated serum IAP level was an independent prognostic marker in all patients.

CONCLUSION

The preoperative serum IAP level may reflect the general condition of colorectal cancer patients, and thus may predict long-term survival independently of stage progression.

Serum immunosuppressive acidic protein levels in patients with severe acute pancreatitis

OBJECTIVES

In severe acute pancreatitis (SAP), immunologic impairment in the early phase may be linked to subsequent infectious complications. Immunosuppressive acidic protein (IAP) is an immunosuppressive factor to be present in serum and ascites of cancer patients, and it is used as a tumor marker and an index of immune status of cancer hosts.

METHODS

We measured serum IAP levels in 42 patients with SAP (Japanese severity score [JSS] > or = 2) on admission and analyzed the relationships with disease severity, pancreatic necrosis, blood biochemical parameters on admission, and clinical outcome (infection and death).

RESULTS

Serum IAP level increased 791 +/- 285 microg/mL (range, 159-1430 microg/mL) on admission and recognized abnormal high level (normal range, < 500 microg/mL) in 37 patients (88.1%). Serum IAP level was significantly lower in patients of stages 3 and 4 (JSS > or = 9) (678 +/- 187 microg/mL) than that in patients of stage 2 (2 < or = JSS < or = 8) (848 +/- 311 microg/mL). It was also significantly lower in patients whose Ranson score was 5 or higher (674 +/- 287 microg/mL) than that in patients whose Ranson score was 4 or less (910 +/- 287 microg/mL). Moreover, it was significantly lower in patients with pancreatic necrosis (693 +/- 194 microg/mL) than that in patients without pancreatic necrosis (922 +/- 336 microg/mL). Among the blood biochemical parameters on admission, serum IAP was significantly negatively correlated with hematocrit, serum lipase, and serum interferon gamma and was significantly positively correlated with serum total protein. Serum IAP levels in patients of stage 2 reached higher peak at 7 days after admission and decreased more rapidly than those in patients of stages 3 and 4.

CONCLUSIONS

Serum IAP levels were elevated in patients with SAP but were significantly lower in patients with higher grade of severity or pancreatic necrosis. These results suggest that serum IAP levels may be related to systemic inflammatory response and reflect the immunoresponsiveness in patients with SAP.

The controversial abscopal effect

The abscopal effect is potentially important for tumor control and is mediated through cytokines and/or the immune system, mainly cell-mediated immunity. It results from loss of growth stimulatory and/or immunosuppressive factors from the tumor. Until recently, the abscopal effect referred to the distant effects seen after local radiation therapy. However, the term should now be used interchangeably with distant bystander effect. Through analysis of distant bystander effects of other local therapies, we discuss the poorly understood and researched radiation-induced abscopal effect. Although the abscopal effect has been described in various malignancies, it is a rarely recognized clinical event. The abscopal effect is still extremely controversial with known data that both support and refute the concept.

Ethanol decreases natural killer cell activation but only minimally affects anatomical distribution after administration of polyinosinic:polycytidylic acid: role in resistance to B16F10 melanoma

BACKGROUND

Natural killer (NK) cells are critical in resistance to B16F10 lung metastases in B6C3F1 mice. Activation of NK cells by polyinosinic:polycytidylic acid (poly I:C; 0.1 mg, intraperitoneally) increases resistance to B16F10 cells. This effect is reduced after administration of ethanol (EtOH; 6 g/kg by oral gavage). The present study was conducted to determine whether decreased resistance is due to alteration of the distribution and/or the activation of NK cells.

METHODS

These parameters were measured in the spleen, lungs, and peripheral blood 4 and 12 hr after EtOH and poly I:C administration. For assessing the time after poly I:C administration during which NK cells are important in resistance to B16F10 cells, anti-NK1.1 antibody was used to deplete NK cells in vivo 48 hr before and 0, 6, 12, and 24 hr after intravenous injection of B16F10 tumor cells.

RESULTS

Depletion of NK cells at any time up to 12 hr after B16F10 administration significantly increased the number of tumor nodules in the lungs, but depletion at 24 hr had a smaller effect. Flow cytometry revealed that there was a small but significant increase in the percentage of NK cells in the lungs at 12 hr, which was not changed by EtOH. Corresponding NK cell lytic function in the lungs was increased significantly at both 4 and 12 hr by poly I:C. However, the increase was not significantly different from the naive control value at 4 hr in mice treated with poly I:C plus EtOH, indicating that EtOH decreased activation of NK cells in the lungs at 4 hr. In the spleen, no treatment significantly altered the percentage of NK cells at 4 or 12 hr. However, poly I:C significantly enhanced lytic function, and this enhancement was suppressed by EtOH (by approximately 50%). In the blood, the only significant change in NK cell percentage or lytic activity was an increase in the percentage of NK cells at 12 hr, which was equivalent in the poly I:C and the poly I:C plus EtOH groups.

CONCLUSIONS

These results demonstrate that EtOH partially abrogates the poly I:C-induced enhancement of resistance to B16F10 cells and that decreased activation of NK cells in the lungs at a critical time early in the response to poly I:C may contribute to this effect. Other parameters could also contribute, but there was little support for an important role for changes in NK cell distribution.

Aberrant expression of interleukin-7 (IL-7) and its signalling complex in human breast cancer

Interleukin-7 (IL-7), a haematopoietic growth factor, is known to induce the differentiation and proliferation of some haematological malignancies including certain types of leukaemias and lymphomas. However, little is known about its role in solid tumours, including breast cancer. In this study, the expression level of IL-7, IL-7 receptor (IL-7R) and their downstream signalling molecules, including the Janus kinases (Jak-1 and Jak-3), phosphoinositide 3-kinase (PI3-K) and signal transducers and activators of transcription (Stat-5) were analysed using the reverse transcriptase-polymerase chain reaction (RT-PCR), real-time quantitative PCR and immunohistochemistry in a cohort of patients with breast cancer. The results were analysed in relation to tumour grade, TNM stage, patients' prognosis (using the Nottingham Prognostic Index (NPI)) and survival. The levels of expression of IL-7, IL-7R, Jak-1, Jak-3, PI3-K and Stat-5 were significantly higher in the most aggressive tumours. With the exception of Stat-5 expression, the transcript copies of IL-7 and all other signalling molecules were higher in patients with the worst prognoses (NPI3) and in patients who died from breast cancer after 72 months of follow-up. This aberrant expression of IL-7 and its signalling intermediates in invasive breast cancers could have significant diagnostic and prognostic implications. Measuring these molecules in breast cancer tissues may provide, for the first time, important molecular indicators of tumour differentiation, aggressiveness, nodal status, prognosis and patient survival.

Prognostic value of preoperative serum immunosuppressive acidic protein in patients with esophageal squamous cell carcinoma

Immunosuppressive acidic protein (IAP) is a potent biological marker of immunological surveillance in patients with malignant tumors. The aim of this study was to analyze the clinicopathologic significance of IAP in patients with esophageal carcinoma. Preoperative serum IAP concentration was measured by enzyme-linked immunosorbent assay in 115 patients with primary esophageal squamous cell carcinomas. The associations between clinicopathologic factors, C-reactive protein (CRP) values and IAP concentration were determined. Prognostic values were determined by multivariate analysis using Cox's proportional hazards model. The IAP concentration is significantly higher in patients with stage II-IV cancers than in those with stage I cancer. Significant differences in IAP concentration were observed depending upon tumor size, tumor depth, lymph node status and CRP values. A high IAP concentration, more than 500 micro g/mL, was an independent prognostic factor. Thus, a high IAP concentration is associated with tumor progression and poor survival in patients with esophageal squamous cell carcinoma.

Bulk cultures of canine peripheral blood lymphocytes with solid phase anti-CD3 antibody and recombinant interleukin-2 for use in immunotherapy

Interleukin (IL)-2 can induce large numbers of lymphokine-activated killer cells in peripheral blood lymphocytes (PBL), but IL-2 alone cannot induce proliferation of a large number of canine (c) PBL. We used the solid phase anti-CD3 antibody and soluble recombinant (r) IL-2 in order to establish a large scale culture method for cPBL. The number of lymphocytes seeded (3 x 10 (7)) increased to 1 x 10(9) after incubation for 10 days. The phenotype of cultured cPBL cells (after 2 weeks) showed a CD4(+) or CD8(+) predominant cell population. The cultured cell solutions were administered with physiological saline intravenously to each dog. After transfusion of the cultured cells, the cPBL counts, especially the number of CD4(+), CD8(+) and CD4(-)CD8 (-)(DN) cells increased significantly in the recipient dogs. Natural killer (NK) cells, gammadeltaT cells and B cells were considered to be present in the DN cell population. The NK cells and gammadeltaT cells showed no adverse reaction to the transfusion of the activated cPBL. Therefore, it is necessary to recognize the B cells present in the DN cell population by detecting CD21(+) cells. In conclusion, the bulk culture system of cPBL with rIL-2 and solid phase anti-CD3 antibody may be useful for the development of novel immunotherapy in dogs.

Targeted proteo-glycomics analysis of Sialyl Lewis X antigen expressing glycoproteins secreted by human hepatoma cell line

Sialyl Lewis X (SLEX) antigen, Neu5Acalpha2-3Galbeta1-4 (Fucalpha1-3) GlcNAc-R, plays important roles in cell-to-cell interaction: for example, the E- and P-selectin-mediated influx of SLEX expressing leukocytes into inflamed areas. A human hepatocellular carcinoma cell line, HepG2 cells, was highly expressed SLEX on secreted glycoproteins and cell surface, in contrast with HuH-7 cells. We identified SLEX expressing glycoproteins in HepG2 cultured medium by two-dimensional polyacrylamide gel electrophoresis, followed by in gel digestion and peptide mass fingerprint using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOFMS), including transferrin, alpha1-antitrypsin, alpha2-HS glycoprotein and beta-glycoprotein. We analyzed N-glycans of these glycoproteins by MALDI-TOFMS in combination with exoglycosidase digestion; our results indicate increases in poly-fucosylated and high-branched N-glycans. High alpha1,3-fucosylation in glycoproteins would be caused by increased expression of alpha1,3-fucosyltransferase activities in HepG2 cells.

Prognostic significance of natural killer cell activity in patients with gastric carcinoma: a multivariate analysis

OBJECTIVE

Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor metastasis, and diminished NK cell activities leads to a high incidence of tumor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined.

METHODS

The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Department of Surgery II, Kyushu University Hospital from 1993 to 1996. All patients were examined for NK cell activity based on a peripheral blood sampling done preoperatively.

RESULTS

Significant association between NK cell activity and clinicopathological parameters including tumor size, lymphatic involvement, vascular involvement, and lymph node metastases was evident. When comparing the two groups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% for those with NK cell activity > 25% lysis and < or = 25% lysis, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression analysis were lymphatic involvement. NK cell activity, depth of tumor invasion, and lymph node dissection.

CONCLUSIONS

These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell activity may be pertinent for the prognosis of patients with gastric cancer and for follow-up clinical management.

Th2 subset dominance among peripheral blood T lymphocytes in patients with digestive cancers

BACKGROUND

Two types of helper T cells (Th), which are categorized as Th1 and Th2 on the basis of cytokine production, have been reported. Th1 cells produce interleukin (IL)-2 and interferon (IFN)-gamma, while Th2 cells secrete IL-4, IL-6, and IL-10. We assessed the intracellular cytokine profiles of CD3/CD4 positive lymphocytes (CD4+ T-cells) in peripheral blood in patients with digestive cancers.

METHODS

Peripheral blood samples were collected from 50 patients with digestive cancers and 35 healthy volunteers. The proportions of CD4+ T-cells producing intracellular cytokines were determined using flow cytometry.

RESULTS

The percentages (mean +/- SD) of CD4+ T-cells producing IL-4, IL-6, and IL-10 in the cancer group (73.9% +/- 13.0%, 73.0% +/- 16.6%, and 58.0% +/- 21.0%, respectively) were significantly higher than in the healthy group (37.4% +/- 12.4%, 37.8% +/- 13.5%, and 34.0% +/- 14.1%, respectively; P <0.01). Proportions of CD4+ T-cells producing IL-4, IL-6, and IL-10 in 10 patients undergoing curative resection had decreased significantly 1 month after surgery (P <0.01). No significant difference was noted between groups in the percentages of CD4+ T-cells producing IFN-gamma.

CONCLUSIONS

Th2-dominant status develops in cancer patients. Such lymphocyte evaluations could find applications in diagnosis and therapeutic monitoring of cancer patients.

Serum hepatocyte growth factor as an index of disease status of patients with colorectal carcinoma

To evaluate the clinical significance of serum levels of hepatocyte growth factor (HGF) in colorectal cancer patients, we measured the venous and portal concentrations of HGF in 60 patients. The tissue concentrations in the tumour and adjacent normal mucosa were also determined. The serum HGF concentration for the peripheral venous blood of the patients was significantly higher than that in normal controls. The content of HGF in cancer tissue was also significantly higher than that in normal mucosa, and it was correlated with the serum HGF concentration for the peripheral venous blood. The serum concentration of HGF reflected pathological features, including tumour size and lymph node or liver metastasis, and it showed an association with various preoperative nutritional parameters and the preoperative haemoglobin level. The serum HGF concentration was also correlated with the serum concentrations of immunosuppressive acidic protein and interleukin-6, indices of the host's immunological condition. Serum HGF seems to be a useful index of the disease status of patients with colorectal carcinoma.

Adverse effects of intraportal chemotherapy on natural killer cell activity in colorectal cancer patients

BACKGROUND

Adjuvant intraportal chemotherapy has been used with a view to prevent the development of metachronous hepatic metastases following curative resection for colorectal cancer. To evaluate the effects of this therapy on systemic antitumor immunological activity, 35 colorectal cancer patients who underwent curative resection were investigated.

METHOD

Among them. 19 had adjuvant intraportal chemotherapy with mitomycin C and 5-fluorouracil (treated group) and 16 had no chemotherapy (untreated group). Natural killer (NK) cell activity, lymphocyte subpopulations, and immunosuppressive acidic protein (IAP) in the peripheral blood were measured serially before and after operation, and the values were compared between the two groups.

RESULTS

The NK cell activity and the percentages of CD16 positive and CD56 positive cells were markedly reduced in the treated group postoperatively. Significant difference was also observed between the two groups on the 4th postoperative day in regard to NK cell activity and CD56 positive cells.

CONCLUSIONS

Intraportal chemotherapy in our study reduced the NK cell activity and its population in the peripheral blood.

Alterations in lymphocyte subsets in blood may predict resectability in carcinoma of cardia or oesophagus

Impaired immune responses in patients with carcinoma of cardia or oesophagus have previously been reported. However, we do not know whether resectability correlates with specific immunological variables. Immunological assessment was performed in 35 such cancer patients including measurement of total T cells (CD3+) and T cell subsets (CD4+ and CD8+), NK cells (CD16+) and B cells (CD19+) in blood. In vitro lymphocyte responses to phytohemagglutinin (PHA) separated from peripheral blood were quantitated. The numbers in peripheral blood of both total T cells (CD3+) and B lymphocytes (CD19+) were significantly lower in the inoperable patients compared to resected patients (P < 0.01). The number of NK cells (CD16+) was, however, not significantly lower in the inoperable patients compared to the patients operated for cure. Lymphocyte responses to PHA in vitro were similar in resectable and non-resectable patients, but significantly lower in inoperable patients compared to the controls (P < 0.01). In conclusion, resectability in carcinoma of cardia or oesophagus is associated with changes in both T (CD3+) and B (CD19+) cell subsets.

Cytokine mRNA expression patterns in human esophageal cancer cell lines

The mRNA expression for 21 kinds of cytokines was measured in six human esophageal cancer cell lines using RT-PCR. More than moderate levels of RNA for IL-1 alpha were expressed in six of six cell lines, IL-1 beta in four, IL-6 in six, IL-7 in five, IL-10 in six, G-CSF in six, GM-CSF in six, SCF in six, MIP-2 beta in two, and LIF in six. None of the tumors expressed detectable message for IL-2, 3, 4, 5, 8, 11, 13, or IRAP after 30 cycles of PCR amplification. IL-1 alpha, IL-6, M-CSF, and GM-CSF levels in the culture supernatants were detectable using ELISA in three of six, four of six, one of six, and six of six ECCs, respectively. IL-1 beta, IL-2, TNF-alpha, and G-CSF were not detectable in all ECCs. There was no correlation between cytokine mRNA expression and production. These results suggest the existence of a complicated cytokine network around esophageal carcinomas that may affect their growth and proliferation.

Natural killer cell activity in patients with pernicious anemia

Patients with pernicious anemia have an estimated risk of gastric adenocarcinoma that ranges from three- to fivefold greater than that of the general population. It has been reported that NK cells may be involved in immunosurveillance against tumor spread. The natural killer cell activity of peripheral blood mononuclear cells was analyzed in 22 patients with pernicious anemia and in 19 healthy controls. Levels of natural killer cell activity against K-562 target cells were similar in control subjects and patients, regardless of gastrin levels and time elapsed since diagnosis. According to quantitative flow cytometry analysis, similar percentages of phenotypically defined NK cells (CD16+) were found in peripheral blood mononuclear cells from patients and healthy controls. Our results show that in pernicious anemia patients, the percentage of NK cells present in peripheral blood mononuclear cells and their lytic activity are normal.