Defective monocyte function in patients with genitourinary carcinoma

Chinese medicinal herbs reverse macrophage suppression induced by urological tumors

Tumors are known to produce factors suppressing macrophage function. In this study we demonstrated in vitro suppression of macrophage chemiluminescent oxidative burst associated with viable cells and cell-free extracts of two urological neoplasms--murine renal cell carcinoma (Renca) and murine bladder tumor (MBT). Suppression was reversed by extracts of two Chinese medicinal herbs, Astragalus membranaceus (AM) and Ligustrum lucidum (LL). Murine macrophage cell line J774 was incubated with either the viable tumor cells or the cell-free tumor extract for 18 hours at 37C and 5% CO2. Chemiluminescent oxidative burst as an indicator of macrophage function was triggered by adding zymosan A suspension containing luminol and assayed in an automated luminometer. Photon emission over time was counted and the results were expressed as integrated photon emission. Significant dose-related depression of oxidative burst occurred with either the viable tumor cells or the cell-free tumor extracts. Depression was partially or completely reversed by the presence of 50-100 micrograms./ml. of either the AM or the LL extract. AM and LL have previously been shown to modulate immune response. Data from this study suggest that they may also exert their antitumor activity via abolition of tumor-associated macrophage suppression.

Immunosuppressive retroviral-related factors in sera of patients with head and neck cancer

The chemotactic responsiveness of mononuclear phagocytes has often been found defective in patients with various malignancies. We have previously reported a defective chemotactic responsiveness in patients with head and neck cancer. Low-molecular-weight factors (LMWFs) have been isolated from tumors and can be held responsible for the inhibitory effect on monocyte chemotactic responsiveness. It is an intriguing new finding that these LMWFs can be neutralized by antibodies reactive to P15E, a structural envelope protein of murine leukemia retroviruses. In this report we describe a relatively easy and rapid method for the detection of immunosuppressive P15E-like factors in the sera of patients with head and neck cancer. The test is based on the monocyte polarization assay. Although only nine head and neck cancer patients were included in this study, the findings indicate that the test might be of value for clinical application. An early detection of a recurrence after treatment might be possible by the finding of a reappearance of the P15E-like factors in patients' sera during follow-up.

Detection of onco-fetal bladder antigen in urine of patients with transitional cell carcinoma

Studies of antigens associated with transitional cell carcinoma were extended by using murine IgM monoclonal antibody E7, developed earlier by this laboratory. These antibodies react preferentially with human bladder tumors and transitional cell carcinoma (TCC) cell line 647V. We now report that monoclonal antibody E7 detected the presence of antigen in midgestational and third trimester amniotic fluids, and in urine of patients with advanced transitional cell carcinoma. Western blot analysis showed that the antigen present in amniotic fluids consists of a sharp band with molecular weight greater than 200 kdaltons. A similar molecular weight pattern was seen with the solubilized membrane of 647V. A sensitive and convenient sandwich ELISA was developed and the urine of patients with bladder cancer was assayed for the presence of the E7 antigen. Antigen was detected in the urine of patients with advanced transitional cell carcinoma but not in the urine of normal adults or in urine from patients with prostate cancer, renal cell carcinoma, or benign prostate hyperplasia. An inhibition enzyme immunoassay was developed with monomeric forms of the E7 antibody and confirmed the presence of antigen in the urine of patients with TCC. We conclude that the E7 antigen is an onco-fetal antigen expressed in patients with transitional cell carcinoma of the bladder.

Antiinflammatory proteins associated with human and murine neoplasms

The immune mechanisms by which a host recognizes and destroys a growing tumor are undoubtedly complex and, as yet, incompletely understood. It is apparent, however, that mononuclear phagocytes play an important role in the defense against neoplastic disease and that the ability of monocytes and macrophages to accumulate at and within a growing tumor is a strict requirement for them to effect that role. Studies from our laboratory as well as those of other investigators have demonstrated that patients with a variety of neoplastic diseases have a specific defect in monocyte chemotactic responsiveness and that this defect is associated with the presence of the tumor. Furthermore, we and others have shown that a similar defect occurs in tumor-bearing rodents, thus allowing model systems to be developed for the study of the mechanisms involved. We have demonstrated that transplanted, spontaneous or carcinogen-induced murine tumors produce low molecular weight proteins which inhibit the accumulation of macrophages to inflammatory foci and that a significant portion, if not all, of these proteins are physicochemically and antigenically related to the retroviral envelope protein p15E. We have shown that p15E itself can inhibit the inflammatory accumulation of macrophages in normal mice. Studies on a wide variety of cancer patients have revealed that the fluids of such patients contain proteins which inhibit the responses of normal monocytes to various chemotaxins and, as in tumor-bearing mice, that these antiinflammatory proteins are antigenically related to retroviral p15E. Recent studies have demonstrated that human tumor cells can simultaneously release factors which are chemotactic for monocytes with those which are p15E-related inhibitors of chemotactic responsiveness, suggesting that the mononuclear phagocyte response to a growing tumor may be, in part, dictated by the balance obtained between various proteins produced by that tumor. The isolation and characterization of endogenous retroviral sequences within the human genome and the observation that the envelope genes of these endogenous sequences are partially homologous to p15E provide potential candidates for the p15E-related inhibitors of chemotactic responses which have been identified from human cancer cells and fluids. Studies now under way in a number of laboratories should provide more definitive answers regarding the nature and source of these p15E-related inhibitors.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of tumor growth on host defenses

Monocytes and macrophages play an important role in host defense against neoplasia. Studies from our and other laboratories have demonstrated that patients with a variety of cancers have a defect in monocyte chemotactic responses. Tumor-bearing mice are also inhibited in their ability to accumulate macrophages to inflammatory foci. We have shown that extracts prepared from murine tumors, as well as the plasma and urine of tumor-bearing mice, contain anti-inflammatory proteins which are antigenically and physicochemically related to the immunosuppressive retroviral envelope protein p15E. Similarly, proteins capable of inhibiting monocyte chemotactic responses are present in human cancerous effusions and can be specifically absorbed by monoclonal antibodies to p15E. Furthermore, we have demonstrated that human malignant and mitogen-transformed cells contain p15E-related antigens. These findings led us to propose a two stage model of tumorigenesis: the first stage involves neoplastic transformation of a cell while the second stage involves activation of a gene coding for a p15E-like protein which allows the transformed cell to escape immune surveillance and go on to become a tumor. Support for this model has come from recent studies which have identified within the human genome an endogenous retrovirus sequence whose envelope gene is partially homologous to a highly conserved region of p15E. Using a synthetic peptide, termed CKS-17, we have shown that this region may be responsible for many of the biological activities of p15E and is capable of suppressing lymphocyte and natural killer cell immune functions as well as those of monocytes and macrophages. Thus tumors may be capable of evading host defense mechanisms by activation of a normal gene related to the immunosuppressive retroviral protein p15E.

Monocyte function in cervical carcinoma: plasma inhibitor of monocyte chemotaxis

Blood monocyte function was tested in 43 untreated patients with carcinoma of the cervix (stages Ib to IIIb) and 50 age-matched controls. Monocyte counts, adhesion to glass, spreading on glass, phagocytosis and killing of Candida albicans, and chemotaxis under agarose were not significantly different between the patient and control groups. In 65% of a further series of 17 patient/control pairs, the plasma of cervical carcinoma patients was shown to contain a cell-directed inhibitor of monocyte chemotaxis. The accumulated evidence indicates that production of such factors by malignant tumors is an important mechanism in counteracting mononuclear phagocyte defense.

Towards a psychobiological model of cancer: biological considerations

The control of tissue homeostasis is extremely complex and many factors contribute to the growth and development of tumours. Although the immune system has been regarded as an essential intermediary between putative psychological factors and the development or restraint of malignant tumours, this review indicates that many other possible mechanisms also exist. Current aspects of tumour biology, immunology and hormonal control systems are reviewed, and detailed psychobiological mediating mechanisms are considered at each stage of tumour development. An approach to the future investigation of this difficult field is proposed.

Evidence in advanced cancer of an activated leukocyte state to explain the reversible defect in transmembrane signaling and leukocyte adherence inhibition to extracts of cancer

When leukocytes bind tumor antigen, a transmembrane signal induces the cascade of physiological changes that result in leukocyte adherence inhibition (LAI). Leukocytes from patients with early stages of cancer exhibited transmembrane potential (delta psi) changes and LAI when incubated with a cancer extract of the same organ and histogenesis, whereas leukocytes from patients with advanced cancer did not. The refractoriness was reversed by transiently raising intracellular cyclic AMP. LAI is produced by leukotrienes and leukocytes from patients with advanced cancer were refractory to leukotriene-induced delta psi changes which was also restored by raising intracellular cyclic AMP. Moreover, leukocytes could be made refractory to delta psi changes: leukocytes from patients with early cancer when preincubated with a breast cancer extract showed no delta psi change with a second exposure; and leukocytes from control subjects preincubated with leukotrienes showed no delta psi change with a second exposure. The responsive population of leukocytes in LAI to either the specific cancer extract or leukotrienes consisted of about 35 to 42% of the adherent leukocytes. The responsive leukocytes in advanced cancer were already nonadherent, accounting for the 39% increased nonadherence with the control extract. Raising cyclic AMP decreased nonadherence by 39%. The results suggest that leukotrienes and other chemoattractants released in vivo by immune cells binding tumor antigen have stimulated the changes in leukocytes in advanced cancer. However, the unresponsiveness seems to be because of appropriate expression of physiological changes triggered by antigen and chemoattractant stimuli.

Mononuclear phagocyte function in head and neck cancer: depression of murine macrophage accumulation by low molecular weight factors derived from head and neck carcinomas

In earlier experiments chemotactic responsiveness of peripheral blood monocytes obtained from patients with head and neck cancers was found to be markedly depressed. In an attempt to attribute this defect in migration to an influence excited by low molecular weight factors of less than 25,000 daltons, derived from the tumor, Amicon filtrates of head and neck cancer cells were administered subcutaneously to C3H mice 24 hrs. before the intraperitoneal injection of concanavalin A. Subsequent macrophage accumulation into the peritoneal cavity was quantified. A clear inhibition of macrophage infiltration was found, particularly when filtrates of poorly differentiated tumors were used. Injection of filtrates from healthy oral mucosa were negative, whereas mouse mammary carcinoma filtrates strongly inhibited accumulation.

Murine malignant cells synthesize a 19,000-dalton protein that is physicochemically and antigenically related to the immunosuppressive retroviral protein, P15E

Murine tumors contain low molecular weight factors that inhibit macrophage accumulation at inflammatory foci. Certain oncogenic murine leukemia viruses contain similar inhibitory activity and the active component of the retroviruses was shown to be the envelope protein P15E. A number of murine malignant and nonmalignant cell lines, as well as primary tumors, have now been examined to determine whether production of retroviral P15E or a related protein is characteristic of neoplastic cells. Tumor lines examined included the Hep 129 hepatocarcinoma, BP8 fibrosarcoma, RL1 lymphoma, and three variants of the B16 melanoma. Tumor lines were virus negative by electron microscopy. Nonmalignant cells examined included ST0, 3T3/BALB, and 3T3/L1 fibroblasts and unstimulated, as well as mitogen-stimulated murine splenocytes. Cells were pulse-labeled with [35S]methionine, proteins immunoprecipitated with two monoclonal antibodies to P15E and analyzed by SDS-PAGE and gel fluorography. All tumor lines synthesized a approximately 19,000-dalton protein that co-migrated with retroviral P15E on SDS-PAGE. None of the nonmalignant cells synthesized this protein. Two-dimensional gel electrophoresis of the proteins precipitated from two B16 melanoma lines by monoclonal anti-P15E showed them to be physicochemically similar to P15E from Rauscher leukemia virus. A competition ELISA assay for P15E was developed and confirmed the results obtained by metabolic labeling and demonstrated P15E-related antigens in the tumor cell lines and also in the ascites fluid of mice injected with Hep 129 cells. More importantly, P15E antigens were expressed in both a spontaneous mammary adenocarcinoma and in a primary methylcholanthrene-induced fibrosarcoma. Nonmalignant tissues from animals bearing these tumors contained no detectable P15E antigen. Extracts from the primary fibrosarcomas, when injected into the thighs of mice, inhibited the intraperitoneal accumulation of inflammatory macrophages. The inhibitory activity was specifically removed by absorption with monoclonal antibody to P15E. These results suggest that synthesis of the immunosuppressive retroviral protein P15E, or a very similar protein, routinely occurs during the growth of murine neoplastic cells. This P15E-related protein is present in spontaneous murine primary tumors as well as in all murine tumor cell lines tested. The expression of such proteins by transformed cells in vivo could confer a selective advantage for their sustained growth since they would be more likely to escape immune surveillance.

Monocyte dysfunction in human cancer

General immunobiologic studies in cancer patients have stressed measurements of lymphocyte function and have commonly ignored the monocyte-macrophage system. A preliminary study of peripheral blood monocyte-macrophage function was undertaken in a group of 90 cancer patients (18 breast, 32 colon, 13 head and neck, 9 lung, and 18 melanoma) and 70 controls. Studies included enumeration of extractible monocytes (EM), quantitation of differentiation into macrophages (macrophage precursor test: MP), evaluation of antibody-dependent cellular cytotoxicity (ADCC), and spontaneous cellular cytotoxicity (SCC) as measured with human erythrocytes, and measurements of monocyte and serum lysozyme activity. Breast cancer patients had normal profiles. Colon cancer patients showed the most profound abnormalities with decreased EM and MP and increased ADCC and SCC. Patients with Stage I and Stage II melanoma had normal profiles, whereas those with advanced melanoma had significantly decreased MP. This defect was restored in two patients by BCG immunotherapy. Head and neck cancer and benign breast disease patients had decreased EM, whereas patients with lung cancer had increased EM. Monocyte lysozyme production was unchanged in the cancer patients compared to controls. Serum lysozyme levels, however, were significantly increased in patients with cancers of the colon, head and neck, and lung. Although patients with localized breast cancer and melanoma had normal levels, these were increased in both patient groups with advanced disease. It would appear that the source of the increased serum lysozyme is probably not the peripheral blood monocytes, but could have originated in the intra-tumoral or tissue-bound macrophages which were not examined. Selected assays of peripheral blood monocyte function were deranged in certain types of cancer patients but were fully normal in others, and did not show consistent correlations with tumor type or stage. Tissue-bound or intra-tumoral macrophages might provide a more fruitful area for study in these disease categories.

Effect of dichloromethylene diphosphonate (Cl2MDP) on immune function in breast cancer patients with bone metastases

Immune function was studied in normocalcemic breast cancer patients with bone metastases treated with either dichloromethylene diphosphonate (Cl2MDP) or placebo. The results showed no significant difference between the two patient groups. This suggests that Cl2MDP does not markedly impair the host's defense mechanisms, and in this respect can be safely used in the treatment of patients with resorptive bone disease.

Quantitative studies of monocyte maturation in patients with malignant melanoma

Peripheral blood monocytes were cultured from normal volunteers and patients with malignant melanoma in a suspension culture containing 50% autologous plasma. The number of monocytes that matured into macrophages in the normal control population was 8.29 +/- 3.14 X 10(4) cells/ml blood, whereas in patients with malignant melanoma the number of matured monocytes was 3.15 +/- 2.80 X 10(4) cells/ml blood. The low macrophage maturation in patients with malignant melanoma was not found to be associated with any serum factors. Furthermore, from morphological studies done using scanning electron microscopy, there was no apparent difference between macrophages maturing from normal individuals or patients with malignant melanoma. From analysis of this adherent cell population there appears to be an intrinsic defeat in the maturation of monocytes in vitro in the case of patients with malignant melanoma.

"Activated" monocytes in gastric cancer patients. I. Increased Fc receptor expression, antibody-dependent cellular cytotoxicity and NBT reduction

The Fc receptor expression, antibody-dependent cellular cytotoxicity (ADCC), and nitro-blue tetrazolium (NBT) reduction of peripheral blood monocytes from 150 patients with different stages of gastric cancer was assessed and compared with results obtained in 77 normal persons and 104 patients with non-malignant diseases of the gut. Monocytes of cancer patients showed an increased ability to form rosettes with human 0, Rh + erythrocytes coated with D-specific antibody. ADCC and NBT reduction were also elevated but no correlation was found with the stage of disease. However, all these phenomena were related to the tumor load as elevated values were the same 4-6 months after surgery in the unresectable-tumor group, while they decreased in patients with resectable tumors. These observations suggest that monocytes of some cancer patients are functionally altered ("activated") in the course of disease.

In vitro monocyte maturation in squamous-cell carcinoma of the lung: influence of humoral factors

A previously described defect of in vitro monocyte maturation in patients with squamous-cell carcinoma of the lung (SCC) has been investigated further. The maturation of patients' monocytes in pooled normal human serum was significantly better than in autologous serum. Conversely, the maturation of normal control monocytes was significantly depressed in patients' serum. The defect has been shown to be due to the presence of an inhibitory factor, rather than the lack of a necessary component in the patients' serum. Artificially aggregated gamma-globulin inhibited monocyte maturation in vitro, but the presence of immune complexes in the serum of many patients with SCC did not correlate well with the depression of in vitro maturation of monocytes from the same patient. Similarly, pregnancy-associated alpha 2-glycoprotein, in increased amounts in the serum of patients with SCC, showed no correlation with monocyte maturation. The addition of soluble extracts of tumour, but not of surrounding normal lung tissue significantly inhibited monocyte maturation. The results suggest that the defective monocyte maturation in patients with SCC is at least in part due to serum inhibitory factors, which are likely to be a heterogeneous group.

Lower relapse rates after neighbourhood injection of Corynebacterium parvum in operable cervix carcinoma

The effect of adjuvant immunotherapy with a single neighbourhood injection of 2 mg C. parvum (CP) was investigated in a randomized study involving 43 patients with carcinoma of the cervix uteri, all of whom were treated by radical surgery. All patients had carcinoma confined to the cervix, the upper part of the vagina or the parametrial region. When the malignancy had spread to the parametrial region, additional postoperative radiotherapy was given. 22 patients received immunotherapy 10 days before surgery, whereas the remaining 21 control patients received no immune stimulation. Only minor side effects of CP were encountered. Follow-up shows a relapse rate of 5% in the CP treated group and of 29% in the controls (P less than 0.05). A further 15 patients with more advanced malignancies were added to our studies. In these, CP stimulation had no effect on relapse rates, but the relapse-free intervals were longer after immune stimulation: control 3.5 months (mean) +/- 1.5 (s.d.), CP 13.0 months +/- 7.0 (P less than 0.05). The number of peripheral T cells and the ability to become sensitized to DNCB were increased after CP stimulation. A decrease was found in the number of blood monocytes and the number of monocytes capable of transforming into active macrophages, indicating a possible sequestration of these cells in the tissues.

Inhibitors of monocyte responses to chemotaxins are present in human cancerous effusions and react with monoclonal antibodies to the P15(E) structural protein of retroviruses

Individuals with cancer have previously been shown to have abnormal chemotactic responsiveness. Surgical removal of the tumor often resulted in normalization of monocyte function, which suggests that human neoplasms might inhibit monocyte chemotaxis by release of soluble mediators. We therefore examined the effects of cancerous effusions on monocyte polarization, i.e., the rapid change in monocyte morphology from round to a triangular "motile" configuration in response to chemoattractants. All 17 malignant effusions, representing 15 tumor types, inhibited monocyte polarization induced by the chemoattractant N-formyl-methionyl-leucyl-phenylalanine by 45-89% (mean 55.9 +/- 12.7%, P less than 0.01) in blinded assays. None of 17 benign effusions signigicantly inhibited polarization (0-15%, mean 6.2 +/- 4.2%). Dilutions of cancerous effusions as low as 1:200 produced inhibition that was time, temperature, and dose dependent . Monocyte polarization induced by activated serum or by chemotactic lymphokine was also blocked by cancerous effusions. The inhibitory activity affected the monocyte directly, and did not destroy the chemoattractant or block the polarization of granulocytes to chemotactic factors. High pressure liquid chromatography of five cancerous fluids revealed three peaks of inhibitory activity: greater than or equal to 200,000, 46,000 +/- 13,000, and 21,000 +/- 3,000 daltons. Fractionation of noncancerous effusions revealed only small amounts of the highest molecular weight inhibitory activity. The inhibitory activity in cancerous effusion was heat stable (56 degrees C, 30 min), trypsin sensitive, and could be absorbed by three different monoclonal antibodies reactive to P15(E), a structural component of type C retroviruses. In contrast, six monoclonal antibodies with other specificities had no effect on the inhibitors of polarization. This study demonstrates that human cancerous effusions contain novel proteins that are potent inhibitors of monocyte function and that are recognized by antibodies reactive to the P15(E) component of retroviruses. By producing such factors, tumor cells may subvert monocyte-mediated surveillance.

Biphasic depression of macrophage function after tumor transplantation

Tumor bearing produces a biphasic depression of macrophage inflammatory responses. Macrophage accumulation was measured on nitrocellulose filters in DA rats transplanted with a DMBA-induced fibrosarcoma and in SJL/J mice transplanted with a first-generation histiocytic lymphoma. The early phase defect was observed 2-5 days and 4-12 days after tumor transplantation in rats and mice respectively. Although transient, its duration could be prolonged by increasing the number of tumor cells injected. An interval of normal responses separated this early defect from a second or late-phase defect which began midway in the clinical course and persisted until death. Transplantation of syngeneic liver cells increased macrophage responses in DA rate but had no effect in SJL/J mice. The demonstration of a biphasic anti-inflammatory effect following tumor transplantation suggests that low doses of tumor cells are effective in inhibiting macrophages and that tumor bearing may alter macrophage responses by more than one mechanism.

Monocyte responsiveness to chemotactic stimuli is a property of a subpopulation of cells that can respond to multiple chemoattractants

The chemotactic migration of leukocytes is preceded by an alteration in the cells' shape from round to a characteristic polar configuration. We have developed an assay that shows that human monocytes, when exposed to chemoattractant in suspension, assume this polarized shape. The three types of chemo-attractants studied, a chemotactic lymphokine, complement-activated serum, and the N-formylated oligopeptides, all induced polarization in a time, temperature, and dose-dependent fashion. Nonchemotactic agents such as mitogens or phorbol myristate acetate did not induce polarization. At 37 degrees C, polarization was rapid (<1 min) and was inhibitable by cytochalasin B, sodium azide, or low temperature. A series of N-formylated oligopeptides were studied and their activity in inducing polarization correlated closely (r > 0.99) with their chemotactic activity. Of the entire population of circulating monocytes there is a subpopulation of cells that is capable of polarizing in response to chemotactic stimuli. The maximum percentage of monocytes which polarized to any chemotactic factor was approximately 60%. Furthermore, the combination of several chemotactic factors could not increase the percentage of polarized monocytes above the maximum obtained with an optimal dose of any single chemoattractant. The data also demonstrate that high doses of a chemoattractant can induce a state of cross-desensitization in monocytes that blocks the response of the cells to other types of chemotactic factors. These results support the concept that the monocytes that do respond to chemotactic stimuli are capable of responding to any of several attractants.

A qualitative and quantitative study of monocytes in patients with malignant solid tumors

Monocytes from 21 patients with cancer of the lung and cancer of the prostate were studied prior to treatment. The absolute circulating monocyte count, serum lysozyme levels and monocyte IgG surface receptors were normal at all stages of the disease. Monocyte chemotaxis was defective in 45% of the patients. Serum chemotatic factor inactivator(s) that inhibit chemotaxis of normal monocytes were detected in 90% of the patients. In two of four patients the chemotactic factor(s) disappeared following surgical removal of localized tumors. The results of the chemotaxis studies may explain the data of defective delayed hypersensitivity reactions frequently seen in patients with malignancies. The defective chemotaxis and the presence of chemotatic factor inactivator(s) may interfere with the ability of monocytes to accumulate as macrophages in tumor sites.

Monocytes and macrophages in malignant melanoma. II. Lysis of antibody-coated human erythrocytes as an assay of monocyte function

Peripheral blood mononuclear cells will lyse antibody-treated human erythrocytes. Using Group A red cells and a hyperimmune anti-A1 serum, we have devised a microassay for the cytolytic capacity of mononuclear cell suspensions. The effector cells responsible for red-cell lysis are mononuclear, adherent and phagocytic, and their activity is blocked by aggregated IgG. Their presence correlates well with non-specific esterase-containing cells and we conclude that they are monocytes. Dose-response curves of red-cell lysis plotted against numbers of monocytes were used to derive a simple parameter expressing the number of monocytes needed to lyse 15% of the 51Cr-labelled red cells. The assay was applied to a group of 27 normal controls and 36 patients with a histologically proven diagnosis of malignant melanoma. The results indicate that monocytes from patients show significantly greater lytic activity than those from the controls. These data suggest that monocytes from cancer patients are in some way activated, and that other defects in monocyte function which have been detected in cancer patients (defective chemotaxis and maturation) may be associated with monocyte "activation".

Monocyte chemotaxis in bronchial carcinoma and cigarette smokers

Chemotaxis of blood monocytes was measured in 31 patients with bronchial carcinoma and 19 cigarette smokers. Thirteen patients with metastatic bronchial carcinoma had significantly less (P less than 0.005) chemotactic response than matched controls. Those with disease confined to the chest, or with recurrent or operable bronchial carcinoma, had no significant depression of monocyte chemotaxis. There was also no significant difference in monocyte chemotaxis between cigarette smokers and matched controls. These results support the concept that in human cancer there is a defect in monocyte chemotaxis, but in bronchial carcinoma significant depression was only apparent in those with advanced disease.

Adjuvant treatment with levamisole in cancer: a review of experimental and clinical data

Animal and human studies of adjuvant treatment with levamisole in cancer are reviewed and discussed. From the animal data it is concluded that the activity of levamisole is dose-dependent, more effective on slow-growing tumors, affects metastasis formation, preferentially is best when levamisole is used as an adjuvant to the usual cytoreductive treatments and that tumor enhancement is not expected. Clinical findings are put into perspective of the animal data and the most appropriate clinical situations are indicated.

Disorders of leukocyte chemotaxis

The rapid accumulation of inflammatory cells at sites of microbial invasion or neoplastic transformation is a central event in immunologically-mediated host defense. The availability of methodology to accurately quantify leukocyte migration in vitro has allowed the disclosure of previously unrecognized clinical disorders, namely leukocyte dysmotility syndromes. Although this area of clinical investigation is in its infancy, one can identify several processes associated with abnormal leukocyte accumulation. Abnormalities of immune recognition, chemotactic factor production, cellular motility or inhibitors of chemotaxis have been identified in different human diseases. In the upcoming years, pharmacological intervention directed at correcting specific causes of leukocyte dysmotility may well enhance our ability to treat certain infectious, inflammatory, and neoplastic diseases.

An inhibitor of macrophage chemotaxis produced by neoplasms

The accumulation of macrophages at neoplastic sites may be an important event in immunologically mediated tumor killing. The implantation of syngeneic neoplasms in mice, however, was found to depress the animal's ability to localize macrophages at inflammatory sites. A low-molecular-weight (6,000 to 10,000) factor released by growing neoplasms that inhibits the accumulation of macrophages in vivo and chemotactic responsiveness in vitro was identified. The factor is active in the inhibition of macrophages and is ineffectual at retarding the migration of polymorphonuclear leukocytes. Neoplastic cells may thus abrogate immunosurveillance by releasing products that prevent potentially tumoricidal macrophages from accumulating at sites of developing malignancies.