The effect of IgG levels on the number of natural killer cells and their Fc receptors in chronic inflammatory demyelinating polyradiculoneuropathy.

BACKGROUND AND PURPOSE: High-dose intravenous immunoglobulin (IVIg) is an established treatment for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Although Fc receptors on natural killer cells have been suggested as a target for IVIg, the pharmacological effects are not yet clarified. We hypothesize that IVIg therapy, dependent on the plasma IgG level, suppresses the cytotoxic capacity by a reduction in numbers of NK cells and their Fc receptor CD16. PATIENTS AND METHODS: Ten consecutive patients with CIDP in maintenance therapy with IVIg were studied before and immediately after the infusion of 0.7-2.0 g/kg IVIg. Peripheral blood mononuclear cell samples from these patients were analyzed immediately after isolation using flow cytometry and cytotoxicity assays. RESULTS: We found that following IVIg treatment, the cytotoxic activity of NK cells in CIDP patients was suppressed, partly caused by a dose-dependent decline in the number of circulating NK cells. In addition, a dose-dependent blockage of CD16 occurred. CONCLUSIONS: The study implies that IVIg infusion induces a substantial decline in the number of peripheral NK cells and a suppression of NK-cell-mediated cytotoxicity. We propose that these impairments of the NK cells contribute to the therapeutic effect of IVIg in CIDP.

Morphological appearance, content of extracellular matrix and vascular density of lung metastases predicts permissiveness to infiltration by adoptively transferred natural killer and T cells.

We have recently shown that adoptively transferred, IL-2-activated natural killer (A-NK) cells are able to eliminate well-established B16-F10.P1 melanoma lung metastases. However, some B16-F10.P1 lung metastases were resistant to infiltration by the A-NK cells and also resistant to the A-NK cell treatment. The infiltration-resistant (I-R) B16-F10.P1 metastases had a unique "compact" morphology compared to the "loose" morphology of the infiltration-permissive (I-P) metastases. Here, we show that I-P loose tumors and I-R compact tumors are also found in lung metastases of mouse Lewis lung carcinoma (3LL), MCA-102 sarcoma, and MC38 colon carcinoma as well as rat MADB106 mammary carcinoma origin. Furthermore, the infiltration resistance of the compact tumors is not restricted to A-NK cells, since PHA and IL-2 stimulated CD8+ T-cells (T-LAK cells) also infiltrated the compact tumors poorly. Analyses of tumors for extracellular matrix (ECM) components and PECAM-1(+) vasculature, revealed that the I-R lesions are hypovascularized and contain very little laminin, collagen and fibronectin. In contrast, the I-P loose tumors are well-vascularized and they contain high amounts of ECM components. Interestingly, the distribution pattern of ECM components in the I-P loose tumors is almost identical to that of the normal lung tissue, indicating that these tumors develop around the alveolar walls which provide the loose tumors with both a supporting tissue and a rich blood supply. In conclusion, tumor infiltration by activated NK and T cells correlates with the presence of ECM components and PECAM-1(+) vasculature in the malignant tissue. Thus, analysis of the distribution of ECM and vasculature in tumor biopsies may help select patients most likely to benefit from cellular adoptive immunotherapy.

Antitumor activity of NK cells.

NK cells have been shown to play an important role in the lungs with regards to tumor cell clearance and resistance of this organ to metastases. Here, we have investigated whether NK cells play a similar role in organs other than the lungs. We conclude that while organ-resistance to metastases correlates well with the NK activity of the host, a clear correlation between NK activity and clearance of tumor cells is found only in the lungs. We also demonstrate that activation of NK cells with the TLR 3 ligand poly I:C results in a substantial increase in the number of organ-associated NK cells. This increase may explain the increased resistance to metastasis seen in many organs after poly I:C treatment. Finally, we present data showing that NK cells activated ex vivo with IL-2 are able to localize to lung tumors following iv adoptive transfer and to significantly reduce the tumors they infiltrate. We conclude that NK cells, which currently are under intense investigation owing to their newly discovered immunoregulatory functions, remain very potent antitumor killer cells capable of killing not only circulating tumor cells, but also well-established micro metastases.

Effect of dendritic cells on flow cytometric quantification of cytomegalovirus-specific, interferon-gamma-producing T cells.

Flow cytometric measurement of intracellular cytokines in T cells exposed to antigen is a widely used method for quantification of an antigen-specific T-cell response. As the frequency of antigen-specific T cells is often very low, any improvement in signal to noise ratio is of great importance. Thus, in this study, the ability of antigen-pulsed dendritic cells (DCs) to increase the number of antigen-specific, interferon-gamma (IFN-gamma)-producing CD4+ T cells measurable both in fresh peripheral blood and in reconstituted frozen blood mononuclear cell (MNC) samples was evaluated. Cytomegalovirus (CMV) was used as antigen in a 10 h assay, using cells from both CMV-seropositive and -seronegative donors. When reconstituted frozen samples were analysed, the general response towards CMV lysate in CMV-seropositive donors was 23-86% lower compared to the corresponding fresh blood samples. Antigen-pulsed DCs could not improve the sensitivity of the intracellular cytokine-detection assay when fresh peripheral blood samples were used. Interestingly, however, the addition of CMV lysate-pulsed DCs to cryopreserved MNC samples substantially increased the frequency of specifically induced IFN-gamma-producing cells to a level comparable to the frequency found in the corresponding fresh blood samples.

Tumor structure and extracellular matrix as a possible barrier for therapeutic approaches using immune cells or adenoviruses in colorectal cancer.

In this article we report about the role that tumor structure and extracellular matrix (ECM) may play in immunotherapy and in gene therapy using adenoviruses. We performed studies in a rat model for colorectal cancer, CC531, and in specimens of human colorectal cancer. The tumors were composed of two compartments, tumor cell nests surrounded by stromal cells. ECM proteins were expressed in the stromal part, where the blood vessels were also located. Furthermore, in several tumors, the tumor cell nests were surrounded by basal membrane-like structures. Therefore, in vascular approaches to treat cancer, therapeutic agents on their route to tumor cells may be hampered by ECM to reach tumor cells. We found that immune cells were abundantly present in tumors from colorectal origin. These cells were, however, not found in direct contact with tumor cells, but mainly in the stromal part of the tumor. Adenoviruses, when intravascularly injected, did not reach tumor cells in the CC531 rat model. Tumor cells were only infected, and even then in limited numbers, in cases of intratumoral injection. We hypothesize that ECM in a tumor is a barrier both for immune cells and for adenoviruses to make direct contact with these tumor cells, and thus limits colorectal tumor therapy.

Tumor blood supply and tumor localization by adoptively transferred IL-2 activated natural killer cells.

The circulatory pattern of IL-2 activated natural killer (A-NK) cells was studied in C57BL/6 mice bearing 10 day-old pulmonary and subcutaneous (s.c.) metastases of the B16 melanoma in order to evaluate the roles of the concentration of A-NK cells in the blood and of tumor blood flow on accumulation of A-NK cells in tumors. Kinetic studies of the presence of A-NK cells in peripheral blood after adoptive transfer revealed that these cells rapidly disappear from the blood. Via intravital microscopy of animals with exposed lung tissue, we have shown that the vast majority of transferred A-NK cells become efficiently arrested within the lung microcirculation at their first encounter with this organ, thereby explaining the fast disappearance of the cells from the bloodstream. Despite the low number of A-NK cells circulating in the blood, systemically injected A-NK cells (20 million per mouse) localized significantly (70-80 million cells/g) into most pulmonary metastases within 8-16 hours. In contrast, very few A-NK cells (< 0.2 million cells/g) were found in the s.c. metastases. Based on measurements of tumor blood flow (showing a classic inverse relationship between tumor size and tumor blood flow) and the blood concentration of A-NK cells, we estimated the highest intratumoral density of A-NK cells that theoretically can be generated by A-NK cells transported to the tumor by way of the blood. In s.c. tumors, the observed density of A-NK cells was at all times lower (10-50 fold) than the estimated density, indicating that only a few percent of the A-NK cells arriving at these tumors become retained in them. In contrast, the observed density of A-NK cells in pulmonary metastases was at all times higher (2-3 fold) than the estimated density. This finding indicates that A-NK cells might not reach the pulmonary metastases solely by way of the blood stream. In conclusion, i.v. injected A-NK cells become immediately entrapped in the lungs and, consequently, circulate poorly. While lung metastases become significantly infiltrated by i.v. injected A-NK cells, metastases in organs down-stream from the lungs become poorly infiltrated. We hypothesize that only a part of the A-NK cells found in lung metastases 8-16 hours following injection reach these metastases by way of the blood-vascular system. They might also migrate into the metastases from the surrounding normal lung tissue.

[Dendritic cells--and their possible applications in cancer therapy]. / Dendritiske celler--og deres anvendelsesmuligheder i cancerterapi.

Dendritic cells (DCs) represent a group of antigen-presenting leukocytes which are very effective in activating resting T-cells. DCs are present in almost all tissues of the body, but they are generally difficult to isolate. The study of human DCs has recently become greatly facilitated due to the advent of methods for isolation and in vivo generation of DCs from blood. Experiments in animal models have shown that DCs loaded with tumour antigens may induce effective immune responses against cancer. Now the potential of vaccination with tumour antigens presented on DCs is being evaluated in cancer patients. Preliminary clinical studies have shown encouraging results.

Secreted and membrane-associated matrix metalloproteinases of IL-2-activated NK cells and their inhibitors.

We have previously documented that rat IL-2-activated NK (A-NK) cells produce matrix metalloproteinase-2 (MMP-2) and MMP-9. In this study, we describe mouse A-NK cell-derived MMPs, including MT-MMPs, and also TIMPs. RT-PCR analysis from cDNA of mouse A-NK cells revealed mRNA for MMP-2, MMP-9, MMP-11, MMP-13, MT1-MMP, MT2-MMP, TIMP-1, and TIMP-2. MMP-2 and MMP-9 expression was confirmed by gelatin zymography. Moreover, we report for the first time that MT-MMPs are expressed by NK cells, i.e., large granular lymphocytes as determined by both RT-PCR and Western blots. TIMP-1 expression was detected as a 29-kDa protein in Western blots. It is intriguing that TIMP-2 protein from A-NK cells was also detected as a 29-kDa protein, which is clearly different from the previously reported molecular mass of 21 kDa in mouse and human cells. In addition, inhibition of MMPs by BB-94, a selective inhibitor of MMP, significantly inhibited the ability of mouse A-NK cells to migrate through Matrigel, a model basement membrane. Taken together, these findings suggest that A-NK cells may therefore use multiple MMPs in various cellular functions, including degradation of various extracellular matrix molecules as they extravasate from blood vessels and accumulate within cancer metastases following their adoptive transfer.

Biodistribution and tumor localization of lymphokine-activated killer T cells following different routes of administration into tumor-bearing animals.

PURPOSE: The efficiency of adoptive cellular immunotherapy of cancer might depend on the number of effector cells that reach the malignant tissues. In the present study, the biodistribution and tumor localization of ex vivo lymphokine-activated T killer (T-LAK) cells was investigated. METHODS: T-LAK cells were labeled with 125I-dU or the fluorescent dye tetramethylrhodamine isothiocyanate (TRITC) and transferred by intravenous, -cardiac, -portal or -peritoneal injection into normal (C57BL/6) mice or mice with syngeneic day-7 to day-12 B16 melanoma metastases established in various organs. The overall biodistribution of the T-LAK cells was measured by gamma counting and their tumor localization by fluorescence microscopy. RESULTS: At 16 h after intravenous injection, the organ distribution of 125I-dU-labeled T-LAK cells was identical in normal and tumor-bearing animals. Fluorescence microscopy of lung tissue from animals receiving TRITC-labeled T-LAK cells revealed, however, a fivefold higher accumulation of T-LAK cells in lung metastases than in the surrounding normal lung tissue (1174 and 226 cells/mm2 respectively). Some pulmonary metastases were, however, resistant to infiltration. Very few intravenously injected cells redistributed to other organs or to tumors in these, since only 60 and 30 T-LAK cells/mm2 were found within metastases of the adrenal glands and the liver respectively. However, following injection of T-LAK cells via the left ventricle of the heart, a threefold increase (from 60 to 169 cells/mm2) in the number of transferred cells in metastases of the adrenal glands was observed. Moreover, following locoregional administration of T-LAK cells into the portal vein, tenfold higher numbers (from 30 to 400 cells/mm2) were found in hepatic metastases than were observed following intravenous or intracardiac injection. In the liver, a surprisingly large number of intraportally injected T-LAK cells (approx. 1300/mm2) were observed to accumulate in the perivascular spaces of the portal, but not the central veins. Even though some superficial ovarian and liver metastases were separated from the peritoneal cavity by only the peritoneal lining, no localization into these metastases was seen following intraperitoneal injection of the T-LAK cells. While treatment of tumor-bearing animals with T-LAK cells plus IL-2 reduced lung metastases by 76% as compared to treatment with IL-2 alone (P<0.03), no significant reduction of liver metastases was seen. CONCLUSIONS: T-LAK cells are able to localize substantially into tumor metastases in various anatomical locations, but mainly following locoregional injection. This finding might have important implications for the design of future clinical protocols of adoptive immunotherapy based on T cells.

Characteristics of tumor infiltration by adoptively transferred and endogenous natural-killer cells in a syngeneic rat model: implications for the mechanism behind anti-tumor responses.

Interleukin-2-activated, cultured NK cells (A-NK) cells were adoptively transferred into a syngeneic rat liver-tumor model. The kinetics of tumor infiltration by NK cells, originating either from adoptively transferred or from endogenous sources, the localization of these cells in the tumor, and their interactions with extracellular-matrix proteins were studied by immunohistochemistry and transmission-electron microscopy. The adoptive transfer of A-NK cells via the hepatic artery and s.c. injections of IL-2 into rats bearing subcapsularly induced CC531 liver tumors, but also IL-2 monotherapy, resulted in a significant increase of the number of NK cells both at the tumor border and in the tumor center. The majority of tumor-infiltrating NK cells was present in the tumor stroma and only occasionally was an NK cell observed in a tumor nodule in direct contact with tumor cells. Observations by electron microscopy suggested that matrix proteins, abundantly present in the tumor stroma but absent in the tumor nodules, provide a substrate for migration of infiltrating cells, whereas tight structures of matrix proteins surrounding tumor nodules provide a barrier for establishment of direct NK-cell-to-tumor-cell-contact. Our results suggest that direct NK-cell-to-target-cell-contact-mediated lysis is of minor importance for attaining an anti-tumor effect in this model. We hypothesize that treatment of tumor-bearing rats with A-NK cells and/or IL-2 initiates a cascade of events (e.g., secretion of tumor-killing cytokines and/or infiltration of other immune cells) ultimately leading to tumor regression.

[Leukocyte filtration in elective colorectal surgery. Reduced transfusion associated immunosuppression after bedside procedures]. / Leukocytfiltrering ved elektiv kolorektal kirurgi. Reduceret transfusionsassocieret immunsuppression efter procedurer ved sygesengen.

The objective of the study was to investigate certain immune parameters in patients undergoing elective colorectal surgery and receiving either whole blood transfusion or leucocyte-filtrated blood. Sixty consecutive patients were randomly allocated to receive either whole blood transfusion or leucocyte-filtrated blood leucocyte when transfusion was indicated. The immune parameters were investigated on the day of surgery and on day 3, 7 and 30 postoperatively. Transfusion with whole blood was followed by a significant decrease in lymphocyte proliferation and CD4+/CD8+ ratio (p < 0.01) as well as a significant increase in soluble interleukin-2 receptor and interleukin-6 (p < 0.01). Furthermore transfusion with whole blood was accompanied by a significant increase in postoperative infectious complications (p < 0.01). Patients transfused with leucocyte-filtrated blood had only minor and passing changes in the immune parameters and developed no infectious complications, indicating that effective leucocyte filtration abolishes transfusion-associated immunosuppression.

Microvessel origin and distribution in pulmonary metastases of B16 melanoma: implication for adoptive immunotherapy.

To elucidate the role of tumor vascularization on the localization of adoptively transferred, interleukin 2-activated natural killer (A-NK) cells, pulmonary B16 melanoma metastases were analyzed with respect to location, morphological appearance, origin and density of microvessels, and infiltration by A-NK cells. The B16 melanoma metastases could be divided into four subtypes according to their location (superficial or deep in the lung parenchyma) and morphological appearance (compact or loose). Localization of adoptively transferred A-NK cells into the four subtypes of B16 pulmonary metastases differed significantly. More than 800 A-NK cells/mm2 were found in metastases of the deep-loose type, compared to approximately 400/mm2 A-NK cells in the superficial-loose metastases, and less than 200 A-NK cells/mm2 in the compact subtype, regardless of its location (deep or superficial). Although the origin (pulmonary or bronchial) of the blood supply to the metastatic subtypes (as revealed by electron microscopic analyses of lungs perfused with a lanthanum solution) did not account for this difference, the density of microvessels in the metastatic subtypes correlated with the number of A-NK cells that localized into these metastases. The resistance of metastases of the compact type to infiltration of adoptively transferred effector cells might explain, in part, why adoptive immunotherapy seldom results in complete eradication of disseminated cancer.

[Erythropoiesis in myelodysplastic syndrome detected by multiparameter flow cytometry]. / Erytropoiesen ved myelodysplastiske syndromer belyst ved multiparameter-flowcytometri.

By staining human bone marrow cells with a monoclonal antibody reacting with surface antigens on erythroid precursor cells (AS-E1) and with propidium iodide reacting with nuclear DNA, we have evaluated the proliferative activity of erythropoiesis in patients with myelodysplastic syndromes using flow cytometric analysis. Comparing 36 patients (13 RA/RAS, 13 RAEB, 10 RAEB-t) with seven normal controls, significant differences in both the percentage of erythroid precursor cells and the fraction of these cells in the S or S-G2M-phase of the DNA cell cycle between the four groups were found. Since neither the percentage of erythroid precursor cells nor their fraction in S or S-G2M phase alone was found to characterize their proliferative activity, we calculated the proliferative fractions of the erythroid cells, i.e. the number of the erythroid precursor cells in S or S-G2M related to all bone marrow cells in S or S-G2M phase. Applying these parameters, we found significantly increased proliferative fractions of erythroid precursor cells in the RA/RAS patients compared to the normal controls (p-0.03 and 0.002 respectively), as well as a highly significant decrease with disease progression.

Accumulation of adoptively transferred A-NK cells in murine metastases: kinetics and role of interleukin-2.

Infiltration of lung metastases by adoptively transferred A-NK cells was time- and dose-dependent. Infiltration became significant 6 hours after injection and reached a maximum after 16-24 hours. When no exogenous IL-2 was administered to support the injected cells, hardly any A-NK cells infiltrated the tumors. More A-NK cells accumulated in the tumors when high doses of IL-2 were given compared to lower doses. Significantly more A-NK cells accumulated in the tumours when the total dose of IL-2 was given as many small doses at short intervals compared to larger doses given less frequently. Use of IL-2 complexed to Polyethylene-glycol (Peg-IL-2) resulted in a significantly better tumor infiltration by A-NK cells than use of regular IL-2. IL-2 administered in mini-osmotic pumps did not lead to a better infiltration than ip injections of the same amount of IL-2. The route of administration of IL-2 did not seem to influence the degree of infiltration.

[Blood transfusion increases the risk of surgical infection]. / Blodtransfusion øger den kirurgiske infektionsrisiko.

In a prospective randomized trial the frequency of infectious complications and natural killer cell function were investigated in 197 patients undergoing elective colorectal surgery and having either no blood transfusion (n = 93), transfusion with whole blood (n = 56), or filtered blood free from leucocytes (n = 48). Postoperative infections developed in 13 patients transfused with whole blood (23%), in one patient transfused with blood free from leucocytes (2%) and in two non-transfused patients (2%) (p < 0.01). Natural killer cell function was significantly (p < 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

Tissue distribution of adoptively transferred adherent LAK cells: role of the route of administration.

The ability of LAK and adherent LAK (A-LAK) cells to migrate to and localize into tumors might be a limiting factor for the efficacy of adoptive immunotherapy. Employing different routes of inoculation of A-LAK cells labeled with 125IUdR, we have investigated how murine A-LAK cells circulate in the bloodstream and localize into various tissues. After intravenous injection, most of the A-LAK cells migrated to the lungs with less than 15% redistributing to other organs. Following left ventricular inoculation, after which the injected cells do not have to pass the lung capillaries before reaching other organs, higher numbers of A-LAK cells were found in liver, carcass, kidney and gut compared to intravenous injection. However, most of the A-LAK cells were cleared from these organs within 24 h, and surprisingly at this time the overall survival of the injected A-LAK cells was not more than 10-20% regardless of the route of injection. We found that a substantial accumulation of A-LAK cells in the liver could be achieved only when the cells were injected directly into the portal vein. Following this route of administration, more than 40% of the injected A-LAK cells were still in the liver at 24 h, whereas only 3-5% had redistributed to other organs. Our data suggest that A-LAK cells circulate inefficiently and survive poorly following systemic administration. However, enhanced accumulation of these cells in a particular organ might be achieved by direct administration of the A-LAK cells into the vessels feeding the organ.