IL-2 And IL-15 Induced NKG2D, CD158a and CD158b Expression on T, NKT- like and NK Cell Lymphocyte Subsets from Regional Lymph Nodes of Melanoma Patients

Regional lymph nodes (LN)s represent important immunological barriers in spreading of malignant tumors. However, they are the most frequent early metastatic site in melanoma. Immunomodulatory agents including cytokines have been included in therapy of melanoma and have shown severe side effects and toxicity. In this sense, there is a growing need for bringing these agents to further in vitro testing that may enlighten aspects of their regional application. Therefore, the aim of this study was to investigate the effect of interleukin (IL)-2 and IL-15, the two cytokines with similar immune-enhancing effects, on the expression of activating NKG2D, inhibitory CD158a and CD158b receptors on CD8+ T, NKT-like and NK cell lymphocyte subsets from regional LNs of melanoma patients. In this study, we showed significant effects of IL-2 and IL-15 cytokine treatments on the expression of activating NKG2D and on inhibitory CD158a and CD158b receptors on lymphocytes, CD8+ T, NKT-like and NK cell lymphocyte subsets originating from regional LNs of melanoma patients. Furthermore, IL-2 and IL-15 by inducing the expression of NKG2D activating receptor on innate and on adaptive lymphocyte subsets and by augmenting NK cell antitumor cytotoxicity that correlated with the cytokine-induced NKG2D expression, increased antitumor potential of immune cells in regional LNs of melanoma patients irrespective of LN involvement. These findings indicate the importance of immune cell population from regional LNs of melanoma patients in the development of immune intervention strategies that may if applied locally increase antitumor potential to the level that controls tumor progressions.

Effect of cytokines on NK cell activity and activating receptor expression in high-risk cutaneous melanoma patients

OBJECTIVE

Stage II melanoma patients have high risk for regional and distant metastases and may benefit from novel therapeutic strategies. To clarify the role of NK cells in Stage II melanoma, we characterized the cytotoxic activity of NK cells and the expression of various activating and inhibitory receptors in high-risk cutaneous melanoma patients (Stages IIB and IIC) compared to low-risk patients (Stage IA).

MATERIALS AND METHODS

Native and cytokine-treated peripheral blood mononuclear cells were used for functional and phenotypical analyses.

RESULTS

Compared to Stage IA-B patients, Stage IIB-C patients showed significantly decreased NK cell activity, as well as decreased expression of the activating NKG2D and CD161 receptors, most likely due to increased serum levels of the immunosuppressive cytokine TGF-β1 in these patients. Interestingly, treatment of periperal blood mononuclear cells with IFN-α, IL-2, IL-12 or the combination of IL-12 and IL-18 significantly induced NK cell activity for both groups of melanoma patients. However, only low-risk patients had a significant increase in the expression of the NKG2D receptor after in vitro treatment with IFN-α, as well as an significant increase in the expression of CD161 after treatment with IFN-α or IL-12. Although IL-2 induced the expression of NKG2D in both groups of patients, this increase was significantly lower in high-risk melanoma.

CONCLUSION

NK cell parameters may be useful as biomarkers of disease progression in localized melanoma patients. Our results further suggest that the use of NK cell-activating cytokines in combination with inhibitors of immunosuppressive factors like TGF-β1 could be a therapeutic option for the treatment of high-risk cutaneous melanoma patients.

Impaired Perforin-Dependent NK Cell Cytotoxicity and Proliferative Activity of Peripheral Blood T Cells is Associated with Metastatic Melanoma

Aims and Background

Patients with metastatic melanoma often have defects in the percentage and function of peripheral blood NK cells, which are involved in the non-specific innate antitumor immune response, and T cells, which participate in the specific acquired antitumor immune response. The aim of this study was to investigate in more detail not only the percentage but also the activation status and function of NK and T cells in patients with metastatic melanoma prior to therapy.

Methods

The percentage of peripheral blood CD56+ NK cells, CD3+ T cells and their CD4+ and CD8+ subsets, as well as the expression of the activation antigens CD69, CD38 and HLA-DR were analyzed by flow cytometry. The functional capacity of NK cells was evaluated by the 51-chromium release cytotoxicity assay, while the proliferative activity of T cells was estimated by the lymphocyte transformation test to mitogen phytohemagglutinin.

Results

The results obtained in this study have revealed a new aspect of NK and T cell dysfunction that is not, as commonly reported, associated with a decrease in their percentage. Moreover, a significant number of the investigated patients had a higher percentage of NK cells that did not lead to improved NK ceil cytotoxicity as a result of the detected defect in the NK cell perforin-mediated cytotoxic mechanism of tumor cell lysis. The impaired proliferative response of T cells was associated with a decreased expression of the activation antigen HLA-DR.

Conclusion

The novel finding in this study of melanoma patients with metastatic disease is the impaired perforin-depen-dent NK cell cytotoxic mechanism, which was recently shown to be primarily responsible for preventing metastasis. Another interesting finding was the generally hyporeactive status of T cells, possibly resulting from persistent antigenic stimulation. The observed dysfunction of NK and T cells in patients with metastatic melanoma prior to therapy point to the need to supplement chemotherapy with appropriate immunotherapeutic agents in order to overcome the immunosuppression associated with advanced malignancy.

Decreased CD161 activating and increased CD158a inhibitory receptor expression on NK cells underlies impaired NK cell cytotoxicity in patients with multiple myeloma

AIM

As innate immune cells natural killer (NK), NK-like T and CTLγδ are important in antitumour response in multiple myeloma (MM), the aim of this study was to investigate some functional and phenotypical characteristics of these cells in MM.

METHODS

29 patients with MM prior to therapy, in clinical stage I-III and 15 healthy controls (HCs) were investigated. Percent of immune cells in peripheral blood, NK cell activity, expression of activating (CD161) and inhibitory (CD158a, CD158b) NK cell receptors on CD3-CD16+ NK cells were evaluated using 51-chromium-release assay and by flow cytometry. Production of interleukin (IL) 2 and tumour necrosis factor (TNF)α was analysed in supernatants from in vitro activated peripheral blood mononuclear cells.

RESULTS

In patients with MM the percent of NK cells and their two subsets did not differ from controls, while NK-like T and CTLγδ cells were significantly decreased. Significant impairment of NK cell cytotoxicity, CD107a expression and interferon γ intracellular level was also shown. There was a significant decrease in CD161 and an increase in CD158a receptor expression on NK cells in these patients. Also IL-2 production was lowest in clinical stage III. However, TNF-α production did not differ between patients and HCs.

CONCLUSIONS

Altered expression of CD161 activating and CD158a KIR inhibitory receptor is responsible for impaired antitumour activity of NK cells in MM patients. These new biomarkers may be helpful for patient selection for immunotherapy with cytokines, and novel KIR blocking monoclonal antibodies that enhance NK cell antimyeloma activity and provide clinical benefit.

Favorable in vitro effects of combined IL-12 and IL-18 treatment on NK cell cytotoxicity and CD25 receptor expression in metastatic melanoma patients

Background

As IL-12 and IL-18 have important immunostimulatory role the aim of this study was to investigate their in vitro effects on functional and receptor characteristics of NK cells and their subsets in healthy controls (HC) and metastatic melanoma patients (MM).

Methods

Peripheral blood mononuclear cells (PBMC) of HC and MM were stimulated with culture medium alone, medium supplemented with IL-12 (10 ng/ml), IL-18 (100 ng/ml) and their combination. NK cell activity was determined using radioactive cytotoxicity assay, while perforin, CD107a and pSTAT-4 expression, IFN-γ production and the expression of NKG2D, DNAM-1, CD161, CD158a/b, CD25, IL-12R beta 1/2 receptors on CD3⁻CD56⁺ NK cells and their CD3⁻CD56^dim+ and CD3⁻CD56^bright+ subsets were analyzed by flow cytometry. Cytokine induced level of DAP10 in PBMC was analyzed by reverse transcription polymerase chain reaction.

Results

IL-12 alone or in combination with IL-18 significantly induced NK cell activity and CD107a degranulation marker expression in MM and HC, while IL-18 alone did not have any effect in patients. The combination of IL-12 and IL-18 significantly increased mean fluorescence intensity (MFI) of IFN-γ in all NK cell subsets in HC and only in the bright subset in MM. MM that belong to M1c group with metastasis in liver and increased LDH serum values had significantly lower increase in NK cell cytotoxicity after combined IL-12 and IL-18 treatment compared to the patients in M1a and M1b categories. These results could be explained by decreased IL-12R expression and lower increase in pSTAT-4 and perforin expression in NK cells of M1c patients after IL-12 and combined IL-12 and IL-18 treatment. IL-18 alone significantly decreased NKG2D receptor expression and level of DAP10 signaling molecule in MM, while combined IL-12 and IL-18 increased the expression of CD25 on all NK cell subsets in HC and MM. Additionally, MM that belong to M1a + M1b group had significantly higher increase in CD25 receptor expression compared to the patients in M1c group.

Conclusions

The novel data obtained in this study support the use of IL-12 and IL-18 in combination for developing new therapeutic strategies for metastatic melanoma especially for patients with better survival rate and prognosis.

Novel aspects of in vitro IL-2 or IFN-α enhanced NK cytotoxicity of healthy individuals based on NKG2D and CD161 NK cell receptor induction

As IL-2 and IFN-α modulate NK cell activity it was of interest to investigate the expression of newly defined NK cell receptors and augmented NK cell activity in healthy individuals after cytokine in vitro treatment. Peripheral blood lymphocytes (PBL) obtained from 31 healthy volunteers treated for 18 h with 200 IU/ml IL-2 and 250 IU/ml IFN-α were evaluated for NK cell cytotoxicity. Expression of NKG2D, CD161, CD158a, CD158b receptors was analyzed on CD3⁻CD16+ NK cells, cytotoxic CD16(bright) and regulatory CD16(dim) subsets by FACS flow. The found induced significant in vitro enhancement of NK cell activity by both cytokines is supported by specific cytokine induction in PBL of pSTAT1 and pSTAT5, determined by Western blotting, as well as induction of IRF-1 transcription. Both cytokines induce significant up-regulation of NKG2D expression while only IFN-α induced significant up-regulation of CD161, with no alteration in KIR expression by either cytokine on CD3⁻CD16+ NK cells. Investigated cytokines did not induce change in NK cell bright and dim subset distribution. Moreover, we find that, not only cytokine receptor induction on the CD3⁻CD16+ NK cells, but also simultaneous increase in their percentage and/or density on CD16(bright) and CD16(dim) subsets, represent good indicators of receptor cytokine-susceptibility. As the role of NK cells has been shown in the loss of tolerance, infection and cancer, the data obtained in this study may be of help in NK cell profiling, by giving referent values of cytokine-induced novel NK cell receptor expression either in evaluation of these diseases or in immunomonitoring during cytokine immunotherapy.

The stage dependent changes in NK cell activity and the expression of activating and inhibitory NK cell receptors in melanoma patients

BACKGROUND

As NK cell antitumor activity is regulated by the balance between numerous activating and inhibitory receptors the aim of this study was to analyze the changes in these receptors expression as well as the differences in their association with NK cell activity in melanoma patients in different clinical stages.

MATERIALS AND METHODS

Forty-three melanoma patients in the three different clinical stages and 17 healthy controls were analyzed for NK cell activity by the standard (51)Cr radioactive assay, as well as for the percentage and absolute number of CD3-CD56+ NK cells and their subsets and the expression of degranulation marker CD107a, activating NKG2D and CD161, and inhibitory KIR, CD158a, and CD158b receptors on CD3-CD56+ NK cells by flow cytometry. IFN-γ and TNF-α PBL production were evaluated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We show that contrary to nonmetastatic, metastatic melanoma patients have significantly impaired NK cell activity, lower CD107a expression, as well as decreased production of IFN-γ and TNF-α. Furthermore, these melanoma patients have a significant decrease in the expression of activating NKG2D receptor, which positively correlates with NK cytotoxicity, and a significant increase in the expression of inhibitory CD158b on CD3-CD56+ NK cells compared with healthy controls.

CONCLUSIONS

In this study, we show that metastatic melanoma patients have significant changes in NK cell activity and the expression of activating as well as inhibitory NK cell receptors. These results indicate that only in this patient group, the blocking of inhibitory or enhancing of activating NK cell receptor expression may promote NK cell-mediated cytolysis.

Distribution of several activating and inhibitory receptors on CD3-CD16+ NK cells and their correlation with NK cell function in healthy individuals

The aim of this study was to estimate the distribution and density of a representative set of activating and inhibitory receptors on gated natural killer (NK) cells, as well as on their bright and dim subsets, and to correlate the receptor expression with NK cell activity for healthy individuals on CD3(-)CD16(+) NK cells. We show that in 43 healthy controls NK cell activity against K562 target cells was 37.34% (E:T, 80:1) by standard chromium release assay. The expression of receptors on NK cells and their subsets was analyzed by flow cytometry. The cytotoxic CD3(-)CD16(bright) NK subset constituted 78.97%, while the regulatory CD3(-)CD16(dim) NK subset constituted 21.03% of NK cells. We show the distribution of NKG2D, CD161, CD158a, and CD158b receptors on CD3(-)CD16(+) NK cells in peripheral blood lymphocytes (PBLs), on gated NK cells, and on the CD3(-)CD16(bright) and CD3(-)CD16(dim) subsets. Contrary to CD158a and CD158b killer immunoglobulin-like receptors (KIRs), there is a significant positive correlation of NKG2D and CD161 expression with NK cytotoxicity. We show the kinetics of change in CD3(-)CD16(+)NK/K562 conjugate composition, together with the stronger target binding capacity of CD16(bright) NK cells. Furthermore, we show that after coculture of PBLs with K562 the expression of CD107a, a degranulation marker, on CD3(-)CD16(+)NK cells and subsets is time dependent and significantly higher on the cytotoxic CD3(-)CD16(bright) NK subset. The novel data obtained regarding expression of NK cell activating and inhibitory receptors for healthy individuals may aid in detecting changes that are associated with various diseases.

CD69 on CD56+ NK cells and response to chemoimmunotherapy in metastatic melanoma

BACKGROUND

The few chemoimmunotherapy trials that together with dacarbazine (DTIC) and interferon-alpha 2a (IFNalpha), include retinoic acid (RA), did not include detailed immunological evaluation of functional and phenotypic natural killer (NK) cell characteristics, and have shown contradictory clinical results.

MATERIALS AND METHODS

Malignant melanoma (MM) patients undergoing phase II-randomized chemoimmunotherapy trials were treated with DTIC, IFNalpha (Hoffmann-La Roche) (group A, n = 31), and with DTIC, IFNalpha and 13-cis-RA (Isotretinoin, Hoffmann-La Roche, Basel, Switzerland) (group B, n = 29). Patients and 42 healthy controls were evaluated by FACS flow analyses for CD3/CD56/CD69 positive cells, NK cytotoxicity in fresh peripheral blood lymphocytes (PBL) and for interferon regulatory factor-1 mRNA expression by reverse transcriptase polymerase chain reaction in treated PBL.

RESULTS

The addition of RA to a DTIC-IFN regime did not bring any therapeutical benefit in terms of response or survival. Immunological follow-up on days 1, 6 and 27 of each therapy cycle shows a significant increase in NK cell activity in both groups, only on day 6 of the first cycle, while CD69+CD56+ expression increased significantly on day 6 of each therapy cycle, in both groups. Evaluation of the dynamics of expression of IRF-1 of in vitro treated PBL, shows its strong and prompt up-regulation by IFNalpha and synergistic effect of IFNalpha and RA combination.

CONCLUSION

The dynamics of the increase in CD69 early activation antigen expression on CD56+ NK cells is systematic and serial with the increase being significantly higher on day six of the first cycle in group B patients with clinical response, compared to those without, indicating possible predictive value of CD69 expression for clinical response to chemoimmunotherapy.

Low expression of CD161 and NKG2D activating NK receptor is associated with impaired NK cell cytotoxicity in metastatic melanoma patients

Natural killer (NK) cells play a role in the innate and adaptive antitumor immune responses. The activity of NK cells is regulated by functionally opposing, activating and inhibitory receptors whose balance ultimately determines whether target cells will be susceptible to NK cell mediated lysis. As melanoma is an immunogenic tumor, the effect of immunomodulating agents is consistently investigated. In this study in 79 metastatic melanoma (MM) patients and 52 controls NK activity, expression of activating NKG2D and CD161 receptors and KIR receptors, CD158a and CD158b, on freshly isolated PBL and NK cells were evaluated. Native NK cell activity of melanoma patients in clinical stage I-III and MM patients was determined against NK sensitive K562, NK resistant Daudi, human melanoma FemX, HeLa and HL 60 target tumor cell lines. In addition, predictive pretherapy immunomodulating effect after 18 h in vitro treatments of PBL of MM patients with rh IL-2, IFN-alpha (IFN), 13-cis retinoic acid (RA) and combination IFN-alpha and RA was evaluated with respect to NK cell lyses against K562 and FemX cell lines. In this study we show for the first time that low expression of CD161 and activating NKG2D receptors, without increased expression of KIR receptors CD158a and CD158b, as well as a decrease in the cytotoxic, CD16(bright) NK cell subset, is associated with a significant impairment in NK cell activity in MM patients. Furthermore, the predictive pretherapy finding that IL-2, IFN, IFN and RA, unlike RA alone, can enhance NK cell activity of MM patients against FemX melanoma tumor cell line can be of help in the design and development of therapeutic regimens, considering that it has recently been shown that low-dose combination of different immunomodulators represents the most promising approach in the therapy of MM.

The comparison of spontaneous LDH release activity from cultured PBMC with sera LDH activity in non-Hodgkin's lymphoma patients

Based on the fact that lactate dehydrogenase (LDH) enzyme is a very sensitive indicator of the cellular metabolic state, aerobic or anaerobic direction of glycolysis, activation status, and malignant transformation, in this study we compared values of the spontaneous LDH release from circulating PBMC with sera LDH activity in 53 different subtypes of non-Hodgkin's lymphoma (NHL) patients. Results shows that serum LDH was significantly (p < 0.05) elevated in comparison to the range values only in the advance clinical stage (III and IV) in all investigated subtypes of NHL according to The Working and REAL classification. On the other hand, the spontaneous LDH release from cultures PBMC is significantly (p < 0.01) elevated in early and advanced stage in all investigated forms of NHL in comparison to healthy controls. Based on consideration that an increase in spontaneous LDH release appears before elevated sera LDH activity, we conclude that determination of spontaneous LDH release by microassay from cultured cells together with other findings may help in the diagnosis of NHL patients, especially in patients with early stage of disease.

IL-2-mediated augmentation of NK-cell activity and activation antigen expression on NK- and T-cell subsets in patients with metastatic melanoma treated with interferon-alpha and DTIC

Considering that well-defined and comprehensive immunological monitoring is the basis for the evaluation of the obtained immunmodulatory effects, we evaluated NK-cell activity, the number of CD3+ CD4+, CD3+ CD8+ T cells and CD16+ CD56+ NK cells, as well as the expression of activation antigens, CD69, CD38 and HLA-DR on CD56+ NK cells, CD8+ and CD3+ T cells, simultaneously with IL-2 and TNF-alpha production, during chemoimmunotherapy with dacarbazine (DTIC) and interferon-alpha (IFN-alpha) in 39 patients with metastatic melanoma. In the first cycle of therapy, there was a significant rise in NK-cell activity, CD4+ T helper cell number, CD4/CD8 T-cell ratio, and the expression of activation antigens CD69 and CD38, on NK and T cells, respectively. However, in the following cycles there was a significant increase only in activation antigens without an increase in the percent or activity of NK cells. The early, but transient, immunopotentiation, present only in the first cycle of combined DTIC and IFN-alpha therapy, suggests that, in spite of increased IL-2 level, associated with augmented NK-cell activity, this therapy has a limited effect probably owing to the adverse effect of persistently high level of TNF-alpha in metastatic disease.

Sulfinosine-induced cell growth inhibition and apoptosis in human lung carcinomas in vitro

In spite of tremendous effort for improved therapy, lung cancer remains the leading cause of cancer-related deaths worldwide. In the present study, we used the novel purine ribunocleoside sulfinosine and evaluated its antiproliferative and apoptotic outcome on the non-small cell lung carcinoma cell line (NSCLC) and the small cell lung carcinoma cell line (SCLC). Using a BrdU incorporation-test sulfinosine inhibited cell growth in a dose dependent-manner. ID50 values were 4.65 +/- 0.17 microM in the case of NSCLC cells, and 3.59 +/- 0.81 microM in the case of SCLC cells. MTT testing revealed that IC50 values were 6.24 +/- 0.77 microM for NSCLC and 5.68 +/- 0.58 microM for SCLC. Inhibitory concentrations (IC50 and ID50) for sulfinosine were nonsignificantly lower in SCLC cells compared to NSCLC cells, indicating similar susceptibility of the cells. Flow-cytometric analysis, TUNEL staining, DNA laddering and cell death ELISA test were used to investigate apoptotic cell death. Our results demonstrated that high concentrations of sulfinosine can cause typical DNA laddering, a hallmark for apoptosis. Evidence of free nucleosomes and enzymatic labeling of fragmented DNA confirmed apoptosis involvement in sulfinosine cytotoxicity. In addition, flow-cytometric analysis showed that 25 microM sulfinosine arrested cell cycle progression at the G2M phase and induction of apoptosis in both cell lines. From these results, we concluded that sulfinosine may act as an anticancer agent and further studies may prove its efficacy in lung cancer cells. Thus the biological effects of sulfinosine may be due to modulation of cell growth, cell death, and cell cycle regulatory molecules.

[The possibilities of modulation of NK cell activity]

The immune system has an important role in tumor appearance and spreading. One of the most efficient subpopulations of cytotoxic cells in the destruction of tumors are NK cells. NK cells are activated and increase their cytotoxic potential and modulate their cytokine production after treatment with IFNgamma, IL-12, TNFalpha and IL-2. The investigation of the activity of NK cells was performed on peripheral blood lymphocytes (PBL) of 16 healthy controls and of 40 patients with metastatic breast carcinoma. Modulation of NK cells was performed with IL-2, IL-7, IL-12, TNFalpha, monoclonal antibodies (mAb) for TNFalpha and TNFalpha receptors type I and II, as well as with sera of healthy controls and patients with breast cancer in different clinical stages. Modulating effect of the applied factors after in vitro treatment of PBL was evaluated by the cytotoxic assay using 51chromium. Our results indicate that IL-2 significantly increased the activity of NK cells of controls and breast cancer patients. The sera of patients with advanced breast cancer significantly reduced NK cell activity. IL-7, IL-12 and mAb for TNFalpha do not significantly change the activity of NK cells. The presence of anti-TNFalpha mAb did not change the inhibitory effect of the sera of breast cancer patients with advanced disease on the activity of NK cells of controls and patients with breast cancer. Blocking of TNFalpha Rcs with mAbs decrease the reactivity of NK cells for IL-2. The treatment of breast cancer patients with advanced clinical stage of breast cancer with IL-2, as an additional therapy, could be advantageous, as NK cells after this treatment increase their cytotoxic activity against tumor cells and can improve therapeutical results.

[Correlation between functional capability and phenotypic characteristics of peripheral blood lymphocytes in patients with malignant melanoma]

Malignant melanoma is well known for its poor response to chemotherapy, radiotherapy and its susceptibility to immunotherapy. Considering that dacarbazine (DTIC) and interferon alpha (IFNalpha) are among the most frequently used agents in the treatment of melanoma, the aim of this study was to evaluate the kinetics of immunological changes during adjuvant treatment of melanoma patients with DTIC or with IFNalpha monotherapy, as well as with their combination in metastatic disease. Pre-therapy values of immunological parameters showed significantly decreased NK cell activity, altered in vitro production of TNFalpha, IL-2 and proliferative response of peripheral blood lymphocytes (PBL), while percentage of PBL subpopulations was unchanged. During therapy, NK cell activity was significantly increased after the 1st cycle of combined chemoimmunotherapy (DTIC + IFNalpha), followed by a significant decrease after the 2nd cycle of therapy. Furthermore, in this group, there was a significant increase in CD4+ T helper cell percentage after the 1st cycle of therapy. Serial monitoring of activation antigens also showed a significant increase in the expression of CD38 on CD8+ cytotoxic T cells, after the 1st and 2nd cycle in combined chemoimmunotherapy group and, after 30 days, in the group of patients treated with IFNalpha, only. The increase in the expression of HLA-DR activation antigen on CD3+ and CD8+ T cells had a gradual increase and significant rise after the 2nd cycle of combine chemoimmunotherapy, only. The dynamic of immunological changes, mostly observed in combined chemoimmunotherapy, and rarely in IFNalpha monotherapy gives valuable insight into induced immunomodulation, suggesting early, but transient favourable changes, that could be prolonged by timely introduction of other immunotherapeutic agents.

[Lactate dehydrogenase (LDH) in peripheral blood lymphocytes (PBL) of patients with solid tumors]

Serum LDH level is a prognostic factor in different malignancies as its increase reflects tumor mass and response to therapy. Serum LDH is the consequence of the disruption of the cell membrane of a large fraction of dividing malignant cells whose metabolic hallmark is anaerobic glycolysis that leads to increased LDH enzyme activity. Moreover, as we have previously shown that spontaneous LDH release from cells represents a measure of cell membrane damage, and this parameter is used for the estimation of cell destruction in cytotoxic assays, the aim of this study was to evaluate the characteristics of LDH activity of PBMC of patients with different solid tumors (non-Hodgkin's lymphomas--NHL, n=47; Hodgkin's disease--HD, n=45; ovarian cancer--OvCa, n=6; breast cancer--BrCa, n=34; thyroid cancer--TyCa, n=3; cancer of PVU--CaPVU, n=4 and head & neck--H&N, n=6) in all clinical stages of NHL and HD and in advanced clinical stages of disease for BrCa, OvCa, CaPVU and H&N. Spontaneous LDH release from PBMC was determined by the spectrophotometric method from supernatants of 8 x 10(6)/ml PBMC cultured for 2 h in RPMI 1640 without phenol red using and LDH substrate mixture. The total LDH activity was determined after lysis of PBMC by ultrasound. The obtained results indicate that PBMC in all the investigated malignancies, compared to control PBMC, demonstrate a significant increase (p<0.01) in spontaneous LDH release act, which correlates with advanced clinical stage in all malignancies except in Hodgkin's disease, in which the spontaneous LDH release was increased in all clinical stages. Contrary to this, the total LDH activity was not increased in PBMC in all investigated tumors. However, the "percent of spontaneous LDH release" was always increased, regardless of the total LDH activity, indicating that spontaneous LDH release is the consequence of PBMC membrane damage present in advanced stages of different solid tumors.

Therapeutic implications of the kinetics of immunomodulation during single or combined treatment of melanoma patients with dacarbazine and interferon-alpha

The therapy of metastatic melanoma has not given satisfactory results. Single chemo- or immunotherapeutic agents in the adjuvant setting or combined chemoimmunotherapy for metastatic disease have generally been evaluated only in terms of clinical benefit. Considering that dacarbazine (DTIC) and interferon-alpha (IFN-alpha) are among the most frequently used agents in the treatment of melanoma, the aim of this study was to evaluate the kinetics of immunological changes during adjuvant treatment of melanoma patients with DTIC or with IFN-alpha monotherapy, as well as by their combination in metastatic disease. The evaluated immunological parameters showed significant early increase in the activity of NK (natural killer) cells, CD4/CD8 ratio, CD4+ T cell number in patients treated with combined chemoimmunotherapy and an increase in expression of the early activation antigen CD38 on CD8+ cytotoxic T cells, both, in patients treated with combined chemoimmunotherapy and with IFN-alpha alone, while, no significant change in any one parameter was detected in the group of patients receiving DTIC. The kinetics of the observed immunological changes, restricted to combined chemoimmunotherapy, indicate that the engagement of antitumor immune response appears early but is short-lived and that this favorable effect should be augmented and prolonged by the timely introduction of additional immunomodulating agents.

Association of NK cell dysfunction with changes in LDH characteristics of peripheral blood lymphocytes (PBL) in breast cancer patients

The cytotoxic activity of NK (natural killer) cells is very important in immunological surveillance against the appearance and especially the spread of malignant disease. The aim of this study was to investigate the function of this subpopulation of cells in breast cancer patients in different clinical stages of disease prior to therapy. NK cell activity was determined in breast cancer patients and healthy controls by three different methods: standard 51-chromium-release assay and by the original colorimetric uncorrected and corrected lactate dehydrogenase (LDH) release assay. A discrepancy was shown between the assays, as the uncorrected LDH assay showed, not only, much higher values, but no stage-dependent depression in NK cell activity compared to the chromium-release assay. Further analyses of separately cultured peripheral blood lymphocytes (PBL) revealed that this difference arose from an increasing, clinical stage-dependent, spontaneous LDH release from PBL of breast cancer patients. Furthermore, a stage-dependent increase in intracellular LDH activity of PBL was found, although without difference in LDH-H and LDH-M isotype ratio, compared to controls. Increased spontaneous LDH release and intracellular LDH activity was more evident in young patients, under 40 years. Correction of the original LDH-release assay for the spontaneous LDH release activity from PBL present in the assay, gave values of NK cell activity comparable to those determined by the chromium assay and indicated that breast cancer patients have a significant depression in NK cell activity which correlates with the stage-dependent increase in spontaneous LDH release. Moreover, as both assays measure the secretory, perforin-mediated, NK cell cytotoxic pathway against tumor cells, it can be concluded that the appearance of spontaneous LDH release is an indicator of cell membrane damage which not only allows the loss of LDH, but also of the components of the secretory killing pathway, resulting in NK cell dysfunction with the progression of disease. The novel findings obtained in this work reveal the association of PBL membrane damage with clinical stage of breast cancer that can, aside from reflecting NK cell depression, underlie the defect in other PBL subsets and subsequently facilitate progression of the malignant process.

[Mechanisms in onset of postoperative immunodepression and its importance in the surgical treatment of cancer patients]

Postoperative immunodepression is inevitable transient path of operative trauma. Changes in the immunologic status are related to the duration of the anesthesia and surgery procedure. Mortality and morbidity and recurrence rate may be related with immunodepression.

Different alterations in lactate dehydrogenase activity and profile of peripheral blood mononuclear cells in Hodgkin's and non-Hodgkin's lymphomas

The enzyme lactate dehydrogenase (LDH) activity of peripheral blood mononuclear cells (PBMC), LDH isotype H and M pattern and PBMC spontaneous LDH release activity were examined in 55 non-Hodgkin's lymphoma (NHL) patients, 46 Hodgkin's disease (HD) patients and 47 controls. The intracellular LDH and M isotype activity of PBMC, their spontaneous LDH release activity significantly increase (p < 0.01) in NHL with progressing histological grade of malignancy. Contrary to this, all classical HD patients have a significant elevation (p < 0.05) of each of these parameters. Furthermore, unlike HD, in NHL clinical stage is associated with significant (p < 0.05) increase in the level of spontaneous LDH release activity in each histological form. It is also shown that spontaneous LDH release activity of PBMC for HD and NHL patients demonstrates significant positive correlation (p < 0.005) with serum LDH level, although elevation of spontaneous LDH release precedes serum LDH increase in both diseases. The results obtained regarding alterations in intracellular, isotype and spontaneously released LDH activity of circulating PBMC show that these parameters are dependent, in NHL patients, on the grade of malignancy and tumor burden, while they are persistently present in HD patients.

A comparison of the NK cell cytotoxicity with effects of TNF-alpha against K-562 cells, determined by LDH release assay

Effects of r h TNF-alpha as a single cytotoxic mediator against K-562 cells was examined by LDH release and compared with NK cell cytotoxicity. The mean values of the percentage of LDH release (x = 6.25 +/- 3.68%, for ten individual experiments) from K-562 cells cultured for 2 h with r h TNF-alpha 100 U/ml of culture medium did not give significant difference in comparison with mean values of percentage LDH release (x = 6.43 +/- 2.97%, for 37 individual experiments) from K-562 cells which were cultured without r h TNF-alpha (Student's t-test, P > 0.05). The results also showed, that in the presence of increasing concentrations of r h TNF-alpha there was no significant increase of LDH release through the cell membrane in these short term incubations. However, significant difference in LDH release from K-562 cells was found after 6 h between cultures treated for 30 min with or without r h TNF-alpha (Mann-Whitney test, P < 0.05). Since TNF-alpha alone shows a lower degree of K-562 cell membrane damage than NK effectors, this suggested that TNF-alpha is neither an only nor a major mediator of cell destruction, based on determination of LDH release.

The difference in NK-cell activity between patients with non-Hodgkin's lymphomas and Hodgkin's disease

Natural killer (NK) cells play an important role in immune surveillance against malignant diseases. Considering the lymphoid origin of malignant lymphomas, as well as scarce data concerning NK-cell function in these neoplasms, we evaluated NK-cell activity in 49 patients with non-Hodgkin's lymphomas (NHL) and 47 patients with Hodgkin's disease (HD), prior to therapy. Using the recommended International Working Formulation and the Ann Arbor staging system for classification of lymphomas we found, by the LDH release cytotoxicity assay, that decreased NK-cell activity (P < 0.05) in NHL patients was essentially related to unfavourable histology (13 indolent lymphomas, 25 intermediate and 11 very aggressive lymphomas were included), but that within these categories clinical stage of the disease also contributed to the degree of NK-cell dysfunction. In contrast, in HD, NK-cell activity was persistently decreased (P< 0.05), compared to controls, irrespective of histological type and clinical stage. It is of interest also that the most profound NK-cell dysfunction that is present and persistent from the onset of HD, and which appears in very aggressive NHL was associated with the phenomenon of increased spontaneous lactate acid dehydrogenase (LDH) release activity from the separated PBMC of these patients. The difference in the level of NK-cell impairment between patients with various histological grades of malignancy in NHL and HD suggests different initial participation of innate immune reactions in these diseases.

[The effect of sera of breast cancer patients on NK cell activity]

INTRODUCTION

The immune system may influence tumorogenesis through natural killer (NK) and specific T cytotoxic cells. It is considered that NK cells, which constitute 15% of peripheral blood lymphocytes, have a main role in defense, due to their ability to destroy tumor cells in situ or in the blood stream in first contact without major histocompatibility restriction. Determination of NK cell activity in malignancies indicates that the evaluation of their activity is more reliable than their number, as well as that IL-2 and interferons increase, while prostaglandines and some hormones decrease their activity. With regard to this, investigations of the effect of sera of patients with malignancies on NK cell activity are being performed [10] in order to see whether the impairment of this activity, which is common in advanced disease, may be due to the presence of different factors in their sera or is the consequence of a defect in NK cells, themselves. This work analysis the influence of sera of healthy persons and patients with different stages of breast cancer on the activity of NK cells of controls and patients with malignancies.

MATERIALS AND METHODS

NK cell activity was evaluated in 58 patients with stage I-III, 11 patients with stage IV of breast cancer and 18 healthy controls. The sera of 30 patients with stages I-III (CaSa), 11 patients with stage IV of breast cancer without or with metastases (CaSb, CaSm, respectively) and 35 healthy controls (ZS/HS) was used for analysis of their effect on NK cell activity. Foetal calf sera (FCS) were used as controls. Isolation and cultivation of peripheral blood lymphocytes: Lymphocytes from 30 ml of blood were isolated by sedimentation on lymphoprep gradient (Nycomed, Norway) and resuspended in RPMI 1640 culture medium without sera in concentration of 4 x 10(6) cells/ml of medium Lymphocytes of each person were treated in a short term culture for 18 h, simultaneously with 10% of inactivated FCS, 10% inactivated healthy sera (HS) and 10% inactivated sera of patients with different stages of breast cancer (CaSa, CaSb, CaSm). NK cell assay: NK cell activity was evaluated as previosly reported by the radioactive 51-Cr release assay. Namely, 100 microl of lymphocytes as effector cells (E) in concentration of 4 x 106 cells/ml of medium and three 1:1 dilutions there of were mixed with 100 ul of target tumor cell line K 562 (T) previosly labeled with 51-chromium (As = 100 microCl) concentration of 5 x 10(5) cells/ml of medium in 96 round bottom plates and incubated for 4 h in an incubator at 37 degrees C with 5% CO2 and humidity. After that the plates were centrifuged and 100 microl of supernatants were used for determination of 51-Cr release in a gamma-counter and expressed in counts per minute (cpm). The percent of specific NK cytotoxicity was determined by the following formula: ((cpm in experimental release - cpm in spontaneous release/ (cpm in maximal release - cpm in spontaneous release)) x 100 where the spontaneous and maximal release were obtained by incubation of tumor cells in culture medium i.e. with 5% Triton x 100 solution, respectively. The results were interpreted by the Mann-Whitney statistical method. RESULTS NK cell activity determined in 18 healthy controls was x = 57.75 +/- 2.21% (E:C=80:1, in patients with breast cancer in clinical stages I-III n=58) it was x = 36.64 +/- 1.92% (E:C=80:1) which is significantly (p < 0.01) below that found in controls, while in patients in stage IV (n=11) it was x = 18.31 +/- 1.38% (E:C=80:1) which is significantly (p < 0.01) below the stages I-III (Table 1). Short term in vitro treatment of PBL in culture medium with FCS gave a significant increase in NK cell activity of both groups of patients: in stages I-III and stage IV (Table 1). Treatment of PBL of patients with stages I-III with sera CaSa, CaSb and CaSm gave a progressively greater inhibition of their NK cell activity compared with FCS (Figure 1). The same type of treatment of PBL of patients with stage IV of breast cancer with HS and CaSb also showed a significant inhibition of their NK cell activity compared to treatment with FCS (Figure 2). Treatment of PBL of healthy controls with CaSa, HS and CaSm demonstrated the same type of progressive inhibition of NK activity (Figure 3).

DISCUSSION

In this work it has been shown that patients with breast cancer in clinical stages I-II, and especially stage IV, have a significantly decreased NK cell activity compared to controls. However, the treatment of both controls' and patients' PBL with sera of patients with different stages of this disease changed NK cell activity. The sera of the first three stages of breast cancer increased this activity, while sera of advanced disease caused a progressive decrease compared to control treatments with FCS. Some of these results were partially obtained in different investigations indicating the presence of stimulative factors in sera of patients with locoregional disease, and inhibitory factors in sera of advanced disease, as well as a slight, probably homeostatic, inhibitory effect of sera of healthy controls 2 These results indicate that the changes in NK cell activity are governed more by the factors in the present sera than by the changes in the activity of NK cells, themselves. The nature of these factors in sera should be further investigated.

[Immunological activity of NK cells]

The article reviews the general characteristics of NK cell which represent a population of lymphocytes engaged through unique mechanisms in immunological defense of the organism. Data concerning morphological characteristics, mechanism of action, perforin, surface antigens and regulation, are given. The new results in human studies related to NK cells are given in detail. The possibility of NK cell activation in vivo and in vitro as applicable methods in adoptive immunotherapy, is described.

[NK cells in malignant diseases]

Data dealing with the role of NK cells in the defense of malignancy, are given. The results of human studies of impaired NK cell activity in various malignancies which show further decrease with the advance of the disease, are described in detail. Causes of diminished NK cell activity are discussed, and the important effects of sera on this activity are pointed out. Characteristics of NK cell subpopulations are given, as well as the possibility of their activation in vivo and in vitro in terms of adoptive immunotherapy.

[Steroid receptors and NK cell activity in patients with breast cancer]

Taking into account the important role of oestrogen and NK cells in the process of cancerogenesis, the content of receptors for steroid hormones and NK cell activity was investigated in 31 patients with breast cancer. The analysis of steroid receptors showed the usual distribution with regard to clinical stage. The values of NK cell ativity in peripheral blood of these patients were decreased x = 38.27 +/- 2.84%) compared to controls (X = 57.76 +/- 2.21%), especially in advanced stages, as was previously shown fot this malignancy. General analysis of values for these two parameters did not show a correlation of NK activity and content of steroid receptors. However, the presence of positive progesterone receptors, which reflects the active effect of oestrogen, was associated with very low NK activity (n = 12 PR+, NK x = 29.47 +/- 3.18%), indicating possible negative regulation of immunological parameters by estrogen.

[Alterations in NK cell activity in the presence of sera of patients with metastases]

In previous reports it was shown that sera of patients with breast cancer in the early clinical stage enhance the activity of NK cells of healthy persons and patients, and that this effect disappears with the advance of the disease. In this studi the effect of sera of 33 breast cancer patients with metastases on NK cell activity of healthy controls was investigated. All of the sera had an inhibitory effect (5 to 84% compared to control sera), the average inhibition obtained by all of the investigated sera was 44% and in one third it was more than 60%. In 21 of 33 patients an increase in the level of immune complexes was found. Investigation of immunoglobulins showed an increase in 12 parients mostly of IgG, which was well correlated with the findings of immune complexes. These investigations clearly show that sera of patients with metastases have an inhibitory effect on NK cell activity of healthy controls, and this most likely contributes to the lower activity of NK cells of patients in advanced stages of this disease, as well as that these sera most often have increased immune complexes, although this was not always proportional to the observed inhibitory effect.

[Immunomodulatory effect of serum on NK cells in vitro in healthy individuals]

The regulatory role of the immune system in malignancies is realized through cytotoxic cells. The main cytotoxic cells that destroy tumor cells are NK cells. Considering this, the activity and regulation of NK cell function is of significance in malignant diseases. Our previous studies showed that different sera had a profound effect on the NK activity of breast cancer patients. In this work we tried to investigate these effects on the NK cell activity of healthy individuals. Our data indicate that the FCS has a profound stimulative effect on the activity of NK cells of healthy donors. We also found that healthy control serum induces a significant inhibition of NK cell activity of these donors. Compared to this effect of healthy sera, sera of breast cancer patients with early clinical stage I-III induced a significant activation of NK cell activity while sera of patients with advanced breast cancer, stage IV with generalized metastases, gave a significant decrease of the NK cell activity of healthy individuals. In this study several sera of patients with stage IV of the disease without metastases gave the greatest inhibition of the NK cell activity which were not found in our previous more extensive investigations of this type of sera. We confirmed that the investigated sera displayed the same effects on the activity of NK cells of healthy persons as they did on NK cells of breast cancer patients. These findings not only indicate the cause of the impaired NK cell activity in patients with malignant disease but also give an indication for immunotherapeutic approaches.

[Selenium, immunity and tumors]

The immune system has one of the essential roles in the appearance and spreading of tumors. It is also well known that the deficit of Se plays an important role in the appearance of many disease, including malignancies. As Se also has an influence on a number of immunological processes. It was interesting to estimate Se content and the function of the immune system in patients with mallignant diseases. Se content was determined in mallignant tissues as well as in the sera of mallignant patients. Immunological reactivity was measured by determination of NK cell activity of patients, or by this determination after in vitro incubation with sera with different amounts of Se. The patients were with various malignancies and the majority was with breast cancer. Se concentration in tissues and sera was in the majority of cases lower than in normal persons. The immunological reactivity measured by NK cell activity, as the most relevant test for antitumor reactivity, was evidently decreased in all the patients, corresponding to the stage of diseases. However, there was no direct correlation between Se content and NK cell activity. It is evident that a very large number of factors are included in the appearance and spreading of malignancies and that they do not have to be necessarily parallel.