Study of the correlation between microfauna and the macrostructure of activated sludge and the efficiency of biological wastewater treatment plants.

Assessment of protozoan populations is an important tool in evaluating the efficiency of activated sludge in the treatment of wastewater. In this process, protozoa play a significant role by grazing on dispersed bacteria, supporting a healthy food web in activated sludge artificial ecosystems. The objective of this study was to verify how the success of the purification process in activated sludge plants, mainly in terms of TSS, BOD, and COD, is related to ciliate protozoa communities and the presence of filamentous bacteria. Samples were collected from five water treatment plants in the Puglia region, in the period May 2007 - April 2008. Microfauna and filamentous bacteria were identified and quantified, and the sludge biotic index calculated. The data show a correlation between the biological components of activated sludge and traditional chemical parameters. Our results indicate that biological analyses represent a valid alternative to traditional chemical testing in assessing the performance of activated sludge systems.

Increased mononuclear cell tissue factor and type-2 plasminogen activator inhibitor and reduced plasma fibrinolytic capacity in children with lymphoma.

Blood clotting activation and fibrin deposition are common findings in lymphoma patients. We evaluated the capacity of peripheral blood mononuclear cells to produce procoagulant activity (PCA) and plasminogen activator inhibitor (PAI) in 12 children with newly diagnosed lymphoma (8 non-Hodgkin's, 4 Hodgkin's) and in 12 matched healthy donors. In the same subjects we also measured plasma antigen levels of tissue-type PA (t-PA), urokinase-type PA (u-PA), PAI-1, PAI-2, and D-dimer. PCA generated by mononuclear cells after incubation for 20 h at 37 degrees C was significantly higher in patients than in controls (p = 0.027). In all samples it was identified as tissue factor by functional criteria (dependence on factor VII). Moreover, culture medium obtained from patients' mononuclear cells after incubation for 20 h at 37 degrees C contained significantly higher amounts of PAI activity and PAI-2 antigen than control samples (p < 0.001). Plasma PAI-1 and t-PA antigens were significantly augmented in patients (p < 0.005), the mean increase of PAI-I being about 5 times higher than that of t-PA. Plasma levels of D-dimer were markedly increased in the patient's group (p < 0.001), whereas u-PA and PAI-2 antigens did not differ from controls. It is suggested that monocytes from lymphoma patients are endowed with functional abnormalities leading to the simultaneous expression of tissue factor and antifibrinolytic activity. These abnormalities, coupled with a reduced plasma fibrinolytic potential, could play an important pathogenetic role in blood clotting activation and fibrin deposition associated with lymphoma.

Inhibitory effect of retinoids on the generation of procoagulant activity by blood mononuclear phagocytes.

Retinoids are known to modulate several functions of mononuclear phagocytes. We have studied the effect of retinyl acetate (RAc) and retinoic acid (RA) on the production of procoagulant activity (PCA) by human peripheral blood mononuclear cells stimulated with endotoxin (1 microgram/ml, 4 or 20 h at 37 degrees C). Both compounds caused a dose-dependent reduction in the expression of cell-associated PCA (from 86 to less than 10% of control in the range of concentration comprised between 0.1 and 100 microM). This effect was also observed when the cells were exposed to retinoids for 10 min and washed before challenge with endotoxin, indicating that it is rapid and irreversible. In contrast, incubation of RAc or RA for 3 h at 37 degrees C with cells that have been already stimulated with endotoxin (20 h at 37 degrees C) remained without influence on cell PCA. The inhibitory action of retinoids was also observed when monocyte-enriched (greater than 85%) preparations or highly purified monocyte-derived macrophages (greater than 99%) were used instead of whole mononuclear cells. BW755C, an inhibitor of cyclo-oxygenase and lipoxygenase, reversed the inhibitory effect of retinoids, whereas acetylsalycilic acid, an inhibitor of cyclo-oxygenase, was inactive, suggesting the involvement of a lipoxygenase product. The inhibition of monocyte/macrophage PCA production and the subsequent reduction of cell potential for fibrin deposition might represent one of the mechanisms whereby retinoids exert their antiinflammatory and immunomodulatory activities.

Cultured human mesangial cells produce both type 1 and type 2 plasminogen activator inhibitors.

Cultured human mesangial cells (HMC) derived from normal kidneys have been shown to synthesize tissue-type plasminogen activator (t-PA) and excess amounts of PA inhibitor type 1 (PAI-1). Conflicting results have been obtained concerning the production of urokinase-type PA (u-PA) and efforts to show PA inhibitor 2 (PAI-2) met with failure. We evaluated the fibrinolytic profile of cultured HMC lines obtained from 12 patients with renal carcinoma and one cadaveric kidney donor. Subconfluent cells (third passage) were incubated overnight in serum-free medium. t-PA, u-PA, PAI-1 and PAI-2 antigens were assayed by ELISA methods and PA and PAI activities by amidolytic methods both in conditioned medium (CM) and cell extracts (CE). Besides PAI-1, PAI-2 antigen was detected in all but one HMC lines. At variance with the former, which was largely released in the culture medium, PAI-2 was mainly cell-associated. t-PA antigen was found in all but two cell lines while u-PA antigen was detected in relatively high concentrations in 8 cell lines. PA activity, identified as u-PA by functional and immunological criteria, was measured in CM of six of the eight u-PA producing cell lines, whereas PAI activity was undetectable or very low in CM of all cell lines, suggesting that PAI-1 was largely inactive. Functional assays of cell extracts demonstrated the presence of PA activity, again identified as u-PA, only in samples (five lines) containing u-PA antigen in excess over PAI-2. PAI activity was found instead in the extracts in which the inhibitor was higher than the activator (six lines) and was identified as PAI-2, as it inhibited u-PA but not single-chain t-PA and was neutralized by a polyclonal anti-PAI-2 antibody. The heterogeneous fibrinolytic pattern of HMC lines was confirmed by mRNA analysis of three representative lines. Results were similar when HMC lines at passage five were used, except that the u-PA content was significantly reduced both in CM and CE. These findings indicate that the fibrinolytic profile of cultured HMC is more complex than previously reported. The production of large amounts of PAI-2 may represent an additional control mechanism of proteinase activity.

Unbalanced coagulation-fibrinolysis potential during L-asparaginase therapy in children with acute lymphoblastic leukaemia.

Treatment of acute lymphoblastic leukaemia (ALL) with L-asparaginase (L-asp) may be associated with thrombotic complications, but the pathogenetic mechanisms of thrombus formation and persistence remain unclear. We studied the procoagulant activity (PCA) of peripheral blood mononuclear cells and some components of the plasma fibrinolytic system in 10 children with ALL undergoing remission induction therapy which includes L-asp. Mononuclear cells obtained 14 days after starting L-asp treatment generated significantly higher amounts of PCA (identified as tissue factor) than cells isolated before the first dose of L-asp and 7 days after the cessation of L-asp administration (p less than 0.01). Augmented PCA coincided with an increase in the plasma D-dimer. The plasma levels of type 1 plasminogen activator inhibitor were found significantly elevated during L-asp therapy (p less than 0.05), whereas plasminogen levels were markedly decreased (p less than 0.05). These findings suggest that, during the course of L-asp treatment, the coagulation-fibrinolysis balance is shifted towards promotion of fibrin formation and deposition. Although it remains to be conclusively established whether L-asp per se or the concurrent administration of multiple chemotherapeutic agents is responsible for these changes, the latter could contribute to the thrombotic complications associated with remission induction therapy for ALL.

Reduction of tumor-associated fibrinolytic-activity by antimetastatic dosages of 2 ru(ii)-dmso complexes in mice bearing lewis lung-carcinoma.

Some Ru(II)-DMSO complexes have antimetastatic properties in experimental tumors. Since plasminogen activators are thought to play an important role in the expression of cancer cell metastatic capacity, we evaluated the effect of two Ru(II)-DMSO complexes on the fibrinolytic activity of Lewis lung carcinoma. Tumor-bearing mice were given daily, for 14 days, an i.p. injection of antimetastatic dosages of cis-RuCl2(DMSO)4 (700 mg/kg/die) or trans-RUCl2(DMSO)4 (37 mg/kg/die), or vehicle. Tumor extracts obtained on day 15 from treatment groups had significantly lower (plasminogen-dependent) fibrinolytic activity than extracts from control animals (p<0.001). Urokinase inhibitor activity in tumor extracts did not differ among groups and did not correlate with plasminogen activator activity, Fibrin autography of control tumor extracts revealed the presence of a main fibrinolytic band co-migrating with urinary plasminogen activator (urokinase-type) and of minor bands with a higher molecular weight. In samples from animals treated with either Ru(II)-DMSO complex the most striking finding was a reduction of the band corresponding to free urokinase. These findings suggest that ruthenium complexes decrease the fibrinolytic activity of tumor cells by reducing urokinase production rather than by enhancing inhibitor production. Treatment of tumor-bearing mice with cis-RuCl2(DMSO)4 at a dosage equimolar to the trans isomer, neither reduced metastasis formation nor decreased plasminogen activator activity of tumor extracts. The depression of tumor-associated proteolytic activity could contribute to the antimetastatic properties of ruthenium complexes.

Enhanced endothelial tissue factor but normal thrombomodulin in endotoxin-treated rabbits.

Exposure of cultured endothelial cells to bacterial endotoxin induces an enhancement of cell procoagulant activity (PCA) and a simultaneous reduction of thrombomodulin activity (TM). We evaluated the effect of endotoxin on the expression of both endothelial PCA and TM in vivo, in rabbits. Animals were given a single i.v. injection of endotoxin (E. coli 0111:B4 LPS, W, 10-200 micrograms/kg); the thoracic aorta was harvested after 2 or 4 hours and placed in an ad hoc device to expose the endothelial surface only. Endotoxin treatment resulted in a dose-dependent increase of endothelial PCA (p < 0.001, at 100 micrograms/kg or more), which was totally dependent on factor VII and thus identified as tissue factor. In contrast, endothelial TM activity, as measured by the rate of thrombin-induced protein C activation, was similar in control and endotoxemic rabbits, even when the animals were given two injections (50 micrograms/kg, 24 h apart), or a continuous infusion (40 micrograms/kg/h during 4 hours) of endotoxin. To explore the effect of endotoxin on TM activity at the microcirculation level, we measured the extent of protein C activation in vivo, induced by a continuous infusion of low doses of thrombin (1 NIH U/kg/min for 60 min). Again, endotoxin administration was not associated with significant changes in TM-dependent protein C activation, as assessed by the anticoagulant activity present in a barium citrate plasma eluate obtained at the end of thrombin infusion. Although reduction of TM during persistent endotoxemia cannot be definitively excluded, our data support a major role of endothelial PCA in LPS-induced coagulative changes.

Increased production of procoagulant activity (tissue factor) by human peripheral blood monocytes after Intralipid infusion.

Intralipid can produce functional and structural changes in the mononuclear phagocyte system. We have investigated the effect of Intralipid on the capacity of peripheral blood human monocytes to produce procoagulant activity when incubated in short term cultures. Twenty-three patients were studied before and after a single infusion of Intralipid 10%. Procoagulant activity was measured on isolated mononuclear cells after incubation (4 h at 37 degrees C) with and without endotoxin, using a one-stage clotting assay. Mononuclear cells obtained after Intralipid infusion produced significantly increased procoagulant activity as compared to their pre-infusion control samples (p < 0.005). Similar results were obtained when freshly collected whole blood was incubated with and without endotoxin (4 h at 37 degrees C) and procoagulant activity was measured on subsequently isolated mononuclear cells (p < 0.005). In all instances procoagulant activity was identified as tissue factor. Patients in the need of Intralipid are often at increased risk for thromboembolic complications and/or disseminated intravascular coagulation because of malignant disease, surgery or infection and there is evidence that the procoagulant activity of mononuclear phagocytes could play a major role in these processes. Our findings suggest that Intralipid might cause a further accentuation of the thrombotic tendency as a result of increased procoagulant activity.

Mechanisms of blood clotting activation in inflammation: the role of mononuclear phagocytes.

The authors review the procoagulant role of mononuclear phagocytes in the activation of blood clotting. Although the intrinsic pathway via the contact system has been considered the most important mechanism leading to fibrin formation, at least in acute inflammation, recent studies strongly suggest a role for the cells of the monocyte-macrophage series, which accumulate in the inflamed areas. These cells, when triggered in vitro by various stimuli (endotoxin, antigens, immune complexes, complement proteolytic products C5a and C3b, allogeneic leucocytes, lymphokines and others), respond with the production of selected procoagulant activities, thereby initiating the coagulation pathways. The most commonly described procoagulant activity has been identified as tissue factor, although prothrombinases and factor X activators have been reported. In addition mononuclear phagocytes can also produce and/or assemble on their surface coagulation factors including f. II, VII/VIIa, IX, X/Xa and V. Available evidence indicates that monocytes/macrophages can respond to appropriate signals and acquire the capacity to activate blood coagulation in vivo also. These "activated" cells expressing procoagulant activity appear to be directly responsible for the local fibrin deposition observed at sites of endotoxin-induced inflammation, of tumours, of cell-mediated immune reactions and possibly of other inflammatory processes.

Treatment with cyclosporin A does not affect macrophage procoagulant activity and plasminogen activator inhibitor in mice.

Using a mouse model, we have investigated the in vivo effect of cyclosporin on macrophage procoagulant activity and on plasma levels of plasminogen activator inhibitor. Procoagulant activity of peritoneal macrophages was studied after treatment of mice with different regimens of cyclosporin (10 to 100 mg/kg body weight) for seven days. No significant difference was found between treated and control animals in both basal procoagulant activity and procoagulant activity generated during short-term culture in the absence or in the presence of endotoxin. These findings are in striking contrast with in vitro experiments showing that cyclosporin induced a significant increase in procoagulant activity when added to peritoneal macrophages from normal animals before challenge with endotoxin (p less than 0.01). Plasma levels of plasminogen activator inhibitor in cyclosporin-treated mice were not different from those of controls. It is suggested that factors other than monocyte-macrophage procoagulant activity or plasminogen activator inhibitor may be important for the postulated 'prothrombotic' action of cyclosporin.

Blood and tissue fibrinolytic profiles in patients with colorectal carcinoma.

In patients with colorectal cancer, profound alterations of the plasminogen activator system have been described at the tumor level, but conflicting results have been obtained for fibrinolytic parameters in plasma. Components of the fibrinolytic system, including tissue-type and urokinase-type plasminogen activators and their inhibitors type 1 and 2, were measured in tissue and/or plasma from 41 patients with colorectal cancer and in 40 controls. Procoagulant activity of freshly isolated mononuclear cells (basal activity) and the procoagulant activity and fibrinolytic proteins produced by the cells after incubation for 18 h without exogenous stimulation were also evaluated. Malignant tissue extracts had significantly higher levels of urokinase-type plasminogen activator and plasminogen activator inhibitor-1, but lower levels of tissue-type plasminogen activator than normal mucosa. Plasminogen activator inhibitor-1 alone was higher in advanced (Dukes' stages C + D) than limited (B) tumors. Plasminogen activator inhibitor-2 was not different in malignant tissue and normal mucosa. Plasma levels of plasminogen activator inhibitor-1 antigen were significantly increased in cancer patients compared with controls, but there were no differences in tissue-type and urokinase-type plasminogen activator, in plasminogen activator inhibitor-2, and D-dimer levels. Intra-patient analysis revealed no significant correlation between tumor and plasma levels of plasminogen activators or type 1 inhibitor. Tissue-type plasminogen activator, but not the urokinase type or inhibitor type 1, was higher in venous than in arterial blood collected at the tumor site during surgery. Basal procoagulant activity of mononuclear cells and the procoagulant activity and inhibitor type-2 produced by the cells after short-term culture were comparable in patients and controls. These findings indicate that, at least in our patients with colorectal cancer, the profound changes occurring at tumor level are barely detectable in the blood. Thus, the clinical relevance of plasma fibrinolytic parameters, especially urokinase-type plasminogen activator antigen, as tumor markers in colorectal cancer remains to be established.

In vitro modulation of cell-mediated immunity by prostaglandin E2. II. Enhancement of spontaneous plaque-forming cell generation.

The effect of the pretreatment of human peripheral blood lymphocytes by Prostaglandin E2 (dissolved in medium) on the spontaneous Plaque-Forming Cell generation has been evaluated. A significant enhancement of immunoglobulin production, markedly increased by the addition of further PGE2 to the pretreated cells, has been demonstrated. Experiments carried out with indomethacin have shown an inhibition of plaque formation, thus indicating that the content of endogenous prostaglandin E2 may play an important role in the enhancement of antibody synthesis, previously described. Results obtained with populations of rosetting and non-rosetting lymphocytes pointed out that non-rosetting cells are exclusively responsive to prostaglandin treatment.

Variability of antibody-specific induction and regulation of plaque-forming cells in cultures of normal human peripheral blood lymphocytes.

PFC have been detected in normal human PBL cultures, immunized with sheep red blood cells (SRBC) and supplemented with Concanavalin-A (Con-A) on day 0 (suppressive effect), and on day 2 (helper effect). Five PBL cultures responded punctually on established days, while four cultures failed to reproduce an enhancing effect when Con-A was added on day 2. In one case only no suppression was observed following addition of Con-A on day 0. Furthermore, it should be taken into consideration the dose of Con-A employed that can give suppressive, enhancing and no effects irrespective of the day of its addition in culture. On the basis of these considerations, it has been concluded that such a method is not suitable for clinical purposes, for instance in patients with immunological disorders, since the individual response to Con-A is extremely variable.

Retinoic acid stimulates plasminogen activator inhibitor 2 production by blood mononuclear cells and inhibits urokinase-induced extracellular proteolysis.

Retinoids have been shown to modulate several functions of mononuclear phagocytes. We investigated the in vitro effect of all-trans-retinoic acid (ATRA) on the production of two major fibrinolytic components, urokinase-type plasminogen activator (u-PA) and PA inhibitor 2 (PAI-2), by human blood mononuclear cells (MNC). ATRA caused a dose-dependent (range 0.01-10 microM) accumulation of PAI-2 antigen and activity into the cell culture medium, with a maximal increase (about 5-fold over control) at a concentration of 1-10 microM. Similarly, a dose-dependent increase in PAI-2 antigen was observed in cell extracts upon ATRA stimulation. Northern blot analysis showed a parallel increase in the amount of PAI-2 mRNA in ATRA-treated cells. Time-course experiments with 1 microM ATRA showed enhanced PAI-2 mRNA expression as early as 2 h, reaching a maximum at 4-6 h and then declining at 18-24 h, and a time-dependent increase in PAI-2 antigen in the cell culture medium. At variance with PAI-2, u-PA was not influenced by the drug. To establish whether ATRA-induced changes influenced the fibrinolytic process, we evaluated the effect of MNC stimulated with ATRA on u-PA-induced degradation of diluted plasma clots. ATRA-treated cells markedly inhibited clot lysis induced by low concentrations of u-PA. The effect was due to enhanced extracellular PAI-2 accumulation since it was observed with conditioned medium from ATRA-treated cells; it was abolished by the addition of neutralizing anti-PAI-2 antibodies and was negligible when single-chain t-PA was used instead of u-PA. Since monocyte/macrophage-mediated, plasminogen-dependent extracellular proteolysis has been proposed as an important mechanism of tissue damage in several inflammatory states, our findings might contribute to better explain the anti-inflammatory properties of retinoids.

Retinoids inhibit the respiratory burst and degranulation of stimulated human polymorphonuclear leukocytes.

Retinoids exhibit a wide spectrum of activities, including antiinflammatory properties. We have investigated the effect of retinoic acid (RA) and retinyl acetate (RAc) on the production of reactive oxygen metabolites and the release of lysosomal enzymes by human polymorphonuclear leukocytes (PMN). Incubation of PMN with RAc or RA (1-100 microM) caused a dose-dependent inhibition (upto 90%) in O2- production and chemiluminescence induced by phorbol myristate acetate (PMA), N-formyl-methionyl-leucyl-phenylanaline (fMLP), opsonized zymosan or ionophore A23187. Both retinoids (1-100 microM) also inhibited, in a dose-dependent way, degranulation induced by fMLP (upto 85% at the highest concentration of RA). These inhibitory effects appear irreversible, since they persist after the drugs are removed and the cells washed before stimulation. Inhibitors of cyclo-oxygenase activity such as acetylsalicyclic acid and indomethacin did not influence the effects of RAc. In contrast, BW755, an inhibitor of both cyclooxygenase and lipoxygenase, reversed the inhibitory action of RAc, suggesting that the effect of retinoids occurs possibly through the mediation of lipoxygenase products. The modulation of PMN oxidative metabolism and degranulation might help explain the antiinflammatory properties of retinoids.

Increased macrophage procoagulant activity but normal endothelial thrombomodulin in rabbits fed an atherogenic diet.

We have studied the procoagulant activity (PCA) of blood and spleen mononuclear phagocytes and the thrombomodulin activity of aortic segments in rabbits fed an atherogenic diet for 6 weeks as compared to rabbits fed a standard diet. Blood monocytes expressed negligible basal PCA (i.e., PCA measured immediately after cell isolation) both in treated and control rabbits. PCA induced by endotoxin in vitro was not different in the two groups. In contrast, dietary treatment resulted in a significant increase in the basal PCA of spleen cells (p less than 0.01). Moreover, the latter produced significantly more PCA than control cells (p less than 0.002) in response to endotoxin in vitro. The thrombomodulin activity associated with aortic endothelium was not different in the two groups of animals despite the presence of visible fatty streaks on the aortic endothelium of treated rabbits. When rabbits were given a single injection of endotoxin, spleen mononuclear phagocytes harvested 60 min after the injection from treated animals expressed three times more PCA (p less than 0.01) than did cells from controls. In all instances PCA was identified as tissue factor. Endotoxin injection did not affect the thrombomodulin activity of thoracic aorta from both control and diet groups. It is suggested that dietary fats may cause early functional changes in mononuclear phagocytes that lead to an increased PCA production both in vivo and in vitro. These data may be relevant to an understanding of the role of monocytes-macrophages in the pathogenesis of atherosclerosis.

Increased procoagulant activity of peripheral blood monocytes in human and experimental obstructive jaundice.

We studied the procoagulant activity of peripheral blood monocytes in 41 patients with severe obstructive jaundice and in 27 nonjaundiced control patients using a one-stage clotting assay. Mononuclear cells from jaundiced patients, tested immediately after isolation, expressed low levels of procoagulant activity, which were, however, significantly higher than in cells from controls (p less than 0.01). In addition, after incubation in short-term cultures with and without endotoxin, these cells generated more procoagulant activity than did the control ones (p less than 0.001). No significant difference in procoagulant activity was found between patients with and without malignancy in either group. The relief of biliary obstruction resulted in the reduction of both serum bilirubin levels and monocyte procoagulant activity. Endotoxin-induced monocyte procoagulant activity was about threefold higher in the jaundiced patients who died than in the survivors (p less than 0.001). In rabbits made icteric by bile duct ligation and separation (15 days), the endotoxin-induced monocyte procoagulant activity was markedly increased as compared with sham-operated animals (p less than 0.005). In all instances, procoagulant activity was identified as tissue factor. The increased capacity of mononuclear phagocytes to produce procoagulant activity might help explain the activation of blood coagulation in severe obstructive jaundice.

Urinary procoagulant and fibrinolytic activity in human glomerulonephritis. Relationship with renal function.

Fibrin deposition in kidney is a common event in some forms of human and experimental glomerulonephritis, and is thought to result from local activation of blood coagulation and/or impaired removal by the fibrinolytic system. We studied the urinary procoagulant and fibrinolytic activities in 46 patients with renal disease (26 with IgA nephritis, 13 with other forms of glomerulonephritis and 7 with non-inflammatory kidney disease) and in 15 matched healthy subjects, as possible indicators of the coagulation-fibrinolysis balance in kidney. Procoagulant activity was slightly but not significantly increased in patients with serum creatinine levels higher than 1.5 mg/dl (group II) as compared with patients with normal creatinine (group I) and controls. It was identified as tissue factor by biological criteria (dependence on factor VII). Fibrinolysis studies showed that both plasminogen activator activity and urokinase antigen were significantly lower in group II than in group I patients and controls (P less than 0.0005). Reduced fibrinolytic activity in patients' urine was due to decreased excretion of urokinase since no inhibitor was detected by both fibrin autography and functional assay. No differences were found between patients and controls in plasma fibrinolytic activity, plasminogen activator inhibitor, and procoagulant activity of blood monocytes. The urinary changes in severe renal disease may reflect an unbalance of the coagulation-fibrinolysis equilibrium in kidney and might be of pathogenetic and clinical relevance.

Procoagulant activity of human alveolar macrophages: different expression in patients with lung cancer.

Mononuclear phagocytes, an integral part of the lymphoreticular infiltrate of many malignant tissues, might contribute to tumor-associated fibrin deposition through the production of procoagulant activity (PCA). We have studied the PCA of human alveolar macrophages in 28 patients with primary lung cancer and in 9 control subjects. Alveolar macrophages (greater than 97% esterase positive) were isolated form bronchoalveolar lavage fluids by adherence onto plastic. PCA was evaluated by a one-stage clotting assay immediately after isolation (basal PCA) and after incubation (4 hr at 37 degrees C) in the absence and in the presence of endotoxin. Cells from control subjects had low basal PCA (3.9 +/- 1.0 units/5 X 10(4) cells) but, upon exposure to endotoxin, they displayed a 5- to 16-fold increase in PCA. In patients, different patterns of PCA were observed. In the 8 patients in whom lavage had been carried out on the contralateral side to the neoplasm, alveolar macrophages behaved essentially like those from controls. In contrast, in the 20 patients in whom macrophage populations close to the site of the tumor were examined, PCA was abnormal in many respects. In 12 of these, alveolar macrophages had basal PCA comparable to or somewhat lower than control cells, but exhibited a poor procoagulant response when incubated in vitro in the presence of endotoxin. Alveolar macrophages from the remaining 8 patients expressed far higher levels of basal PCA than control cells (25.1 +/- 5.9 units as compared to 3.9 +/- 1.0 units/5 X 10(4) cells). These cells retained their ability to respond to endotoxin in vitro with a 3-fold increase in PCA. In all instances, alveolar macrophage PCA had the characteristics of tissue factor. These data suggest that the presence of primary lung cancer may modulate the expression of PCA in alveolar macrophages close to the tumor site. PCA might be useful to better characterize the functional state of macrophages near the tumor.