Methylprednisolone in high doses gives different effects on the early and the late part of complement

The effects of methylprednisolone (MP) on endotoxin-induced activation of complement were studied in citrated pool plasma. Complement activation was tested in two immunoassays: one evaluating C3 activation fragments (C3act) and the other the terminal complement complex (TCC). These components are indicators of initial and terminal complement activation, respectively. Plasma samples were obtained at 1, 2, 4 and 6 h of incubation. Plasma containing endotoxin (2.10(9) ng/l) without MP revealed a marked increase of both C3act and TCC after 1 h. MP in high doses (10 mg/ml) gave an additive effect on activation of the initial part of the complement cascade compared to test plasma containing only endotoxin. In contrast, endotoxin-induced activation of the terminal part of the complement cascade was inhibited by the same dose of MP. The influence of lower doses of MP (0.1 and 1 mg/ml) on endotoxin-induced activation of complement was insignificant. Interestingly, MP without endotoxin induced activation of the initial part of complement. In test plasmas containing 5 and 10 mg/ml of MP (without endotoxin) marked increases of C3act values were seen. Despite this obvious activation of the early part of complement, only insignificant changes were found in TCC values. Test plasmas containing 0.1 and 1 mg/ml of MP revealed only minor changes in both C3act and TCC. In conclusion, the present study shows that high doses of MP activate the initial part of complement and that the endotoxin-induced activation of this cascade system was facilitated by MP. The terminal part of complement was, on the other hand, inhibited by high doses of MP.     

Anaphylatoxins and terminal complement complexes in pancreatitis. Evidence of complement activation in plasma and ascites fluid of patients with acute pancreatitis

Complement activation has been proposed as a mediator of remote complications of acute pancreatitis. Thirty-seven patients with acute pancreatitis were studied with respect to the formation of anaphylatoxins (C3a/C3adesArg, C5a/C5adesArg) and terminal complement complexes (TCC) in plasma and ascites fluid. The patients were classified according to Ranson's criteria. Eighteen patients with moderate or severe pancreatitis had higher maximum plasma C3a/C3adesArg and TCC concentrations than 19 patients with mild pancreatitis. During convalescence, the concentrations had returned to normal. High concentrations of C5a/C5adesArg and TCC were also found in ascites and pancreatic cyst fluid, drawn from patients with moderate or severe pancreatitis. As the terminal complement pathway activation is involved in reactive lysis and anaphylatoxins increase vascular permeability, anemia and impaired respiration in these patients may be influenced by complement activation.     

Complement activation following multiple injuries

Complement activation was evaluated by assay of plasma C3dg and the terminal complement complex (TCC) in 19 patients with multiple injuries. In the nine patients with thoracic involvement, statistically significant increase of plasma TCC was found at first sampling (average 90 min post-trauma), and of C3dg after 24 hours. Such increase was not found in the ten patients without thoracic involvement. Heightened granulocyte elastase activity was found in bronchial lavage fluid 90 min after the trauma in three patients with thoracic injury. Pulmonary insufficiency (pO2/FiO2 less than 16 kPa on intermittent positive-pressure ventilation) arose in four patients. All four had raised plasma levels of TCC or C3dg on arrival at the hospital. Six patients with complement activation did not show pulmonary insufficiency. Although the series was relatively small, the results indicate that thoracic injury is particularly associated with complement activation, and that complement activation alone does not suffice to produce post-traumatic pulmonary insufficiency.     

Different activation patterns in the plasma kallikrein-kinin and complement systems during coronary bypass surgery

Components of the plasma kallikrein-kinin and complement systems were determined in patients undergoing open heart surgery with cardiopulmonary bypass. Spontaneous kallikrein activity (KK), plasma prekallikrein (PKK), functional kallikrein inhibition capacity (KKI), C3 activation products (C3-act), and the terminal complement complex (TCC) were measured. A marked, transitory increase in KK and a decrease in PKK were found prior to cardiopulmonary bypass just after heparin injection. An additional decline in PKK and KKI during bypass with a return to near control levels in the postoperative period was observed. C3-act increased in all patients during bypass, reaching a peak value at wound closure. The TCC concentration also increased significantly during cardiopulmonary bypass, returned to control levels in the early postoperative period, and then increased again in the late postoperative period. It is concluded that activation of the kallikrein-kinin system started after injection of heparin, prior to cardiopulmonary bypass. Activation of both the initial and the terminal complement cascade, however, started only after onset of cardiopulmonary bypass.     

Terminal complement complexes in acute poststreptococcal glomerulonephritis

Activation of the complement cascade occurs in most cases of acute poststreptococcal glomerulonephritis (APSGN) and results in the formation of the terminal complement complexes (TCC). To examine the possible role of TCC in the pathogenesis of glomerular injury in APSGN, we studied 30 patients with the clinical diagnosis of APSGN. All patients had an elevated plasma SC5b-9 concentration at the onset of clinical nephritis. Serial plasma concentrations showed an inverse linear relationship with time after onset of clinical disease (r=–0.59,P=0.0008), while plasma C3 concentrations showed a positive linear relationship (r=0.78,P=0.0001). Renal biopsies of 5 patients demonstrated co-localization of C5b-9, S-protein, and C3 deposition in a glomerular capillary loop and mesangial distribution. Urinary excretion of TCC in the acute phase of APSGN was not elevated and was not a useful marker of disease activity. These data suggest that in APSGN with terminal complement pathway activation the local generation of TCC may contribute to the pathogenesis of the disease.     

Anaphylatoxin and terminal complement complexes in red cell salvage

Thirteen patients undergoing elective orthopedic surgery were studied regarding anaphylatoxin (C3a and C5a) and terminal complement complex (TCC) formation in association with red cell salvage. The auto-transfusion equipment gave a centrifuged and washed erythrocyte fraction. The concentrations of C5a and TCC were not increased but elevated C3a levels were found in the suspension. After infusion of the erythrocyte fraction to the patient, no signs of systemic complement activation were observed. Thus, plasma levels of C3a, C5a and TCC were within the normal range in all the patients before and after autotransfusion. This study indicates that the complement system is activated in the cellsaver equipment. The washing procedure, however, seems to eliminate most of the anaphylatoxins and terminal complement complexes. No extensive systemic activation of complement seems to occur in association with autotransfusion to patients undergoing elective surgery.     

Removal of activated complement from shed blood: comparison of high- and low-dilutional haemofiltration

Background : Perioperative blood salvage is associated with release of inflammatory mediators. Depending on type of processing, the complement system is activated to some extent in the final blood product. The aim of the present study was to evaluate a haemofiltration technique concerning complement system activation and whether the volume of added saline will have an influence on the elimination of activated complement during processing.
Methods : Sixteen patients undergoing total hip arthroplasty received wound blood salvaged intraoperatively with a haemofiltration technique. Saline was added to the reservoir for washing in a ratio of 1:1 or 5:1 of estimated blood volume. Samples for determination of the anaphylatoxins C3a and C5a, and the terminal SC5b–9 complement complex (TCC) were drawn from the patients, the collected blood, the ultrafiltrate and the processed blood.
Results : Increased concentrations of C3a, C5a and TCC were found in aspirated and processed blood. Haemofiltration did not reduce the concentrations of these factors, except that of C3a in the group where saline was added in a ratio of 5:1. There were no increased concentrations of C3a, C5a or TCC in the patient plasma after reinfusion. No differences in blood pressure, heart rate, pH, arterial oxygen tension, arterial carbon dioxide tension, or base excess were found in association with rein-fusion of the blood.
Conclusion : Collected shed blood washed through haemofiltration contained moderately elevated concentrations of C3a, C5a and TCC. Reinfusion of the blood neither led to increased systemic concentrations of complement activation products, nor to disturbances in haemodynamic or biochemical parameters.     

Ketamine suppresses endotoxin-induced NF-kappaB activation and cytokines production in the intestine

BACKGROUND: Ketamine has been advocated for anesthesia in endotoxemic and other severely ill patients because it is a cardiovascular stimulant. However, ketamine also suppresses serum levels of endotoxin-induced tumor necrosis factor-alpha, and reduces mortality in mice in endotoxin shock. Our study was designed to investigate the protective effect of ketamine on the endotoxin-induced proinflammatory cytokines and nuclear factor kappa B (NF-kappaB) activation in vivo. METHODS: Adult male Wistar rats were randomly divided into six groups: saline controls; rats challenged with endotoxin (5 mg kg(-1)) and treated with saline; challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (0.5 mg kg(-1)); challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (5 mg kg(-1)); challenged with endotoxin (5 mg kg(-1)) and treated with ketamine (50 mg kg(-1)); and saline injected and treated with ketamine (50 mg kg(-1)). TNF-alpha, IL-6 and NF-kappaB were investigated in the tissues of the intestine (jejunum) after 1, 4 and 6 h. RESULTS: Endotoxin caused transient production of TNF-alpha and IL-6 and activation of NF-kappaB in the intestine at peak times of 1, 4 and 1 h, respectively. Ketamine 0.5 mg kg(-1) suppressed endotoxin-induced TNF-alpha elevation and inhibited NF-kappaB activation in the intestine; a dose of 5 mg kg(-1) was required to inhibit IL-6. CONCLUSION: Ketamine suppresses the production of proinflammatory cytokines such as TNF-alpha and IL-6 in the intestine, possibly via inhibition of NF-kappaB.     

Complement activation by extracorporeal circulation: effects of precoating a membrane oxygenator circuit with human whole blood

In an in vitro study of extracorporeal circulation (ECC), uncoated oxygenators (UC), oxygenators precoated with whole human blood (CN) and oxygenators precoated with blood and then rinsed with Ringer's acetate (CR) all significantly (p less than 0.001) activated the initial and terminal parts of the complement cascade. After 60 min C3 activation had increased by 692% (UC), 750% (CN) and 393% (CR), and terminal complement complex (TCC) concentrations by 194% (UC), 215% (CN) and 273% (CR). C3 activation was significantly (p less than 0.05) less in the CR than in the other groups. There was no statistical intergroup difference in increase of TCC concentration. Complement activation was accompanied by a significant drop in neutrophil counts, which was uninfluenced by coating or rinsing. The observed dissociation of the complement cascade shows that assessment of activation products from both parts is necessary for evaluation of total complement activation. The study suggests that protein precoating may improve biocompatibility of ECC.     

Terminal complement complexes and anaphylatoxins in septic and ischemic patients

Terminal complement complex (TCC) and anaphylatoxin formation in 18 patients with sepsis and 20 patients with acute limb ischemia were studied before the start of treatment and seven days later. The septic or ischemic patients had elevated levels of plasma TCC before start of therapy. In successfully treated patients these concentrations were within the normal range one week later. Similarly, the plasma anaphylatoxin level was increased before therapy and returned to the normal range within seven days. Escherichia coli incubated in vitro in fresh human serum at body temperature started formation of TCC in a dose-related manner. As complement will induce cellular lysis via TCC and edema via anaphylatoxins, anemia and impaired respiration in these patients may be influenced by increased concentrations of terminal complement complexes and of C3a and C5a.     

A single dose of endotoxin activates neutrophils without activating complement

Both complement (C) and neutrophils (PMN) are activated in critically ill patients. To evaluate the role of endotoxin in this response, we studied C activation products and PMN cell surface receptors in seven normal subjects before and after endotoxin (USRef 20 U/kg) or saline solution administered on separate occasions. By 4 hours, with endotoxin only, all subjects had myalgia, headache, an increase in body temperature and heart rate, and leukocytosis that returned to normal by 24 hours. At the same time, PMN cell surface receptors for the complement opsonin C3b increased, as measured by indirect immunofluorescence, rising to 251 +/- 44% of baseline by 4 hours (p less than 0.01) and remaining elevated at 24 hours (237 +/- 16%, p less than 0.01). PMN receptors for iC3b increased to 308 +/- 49% of baseline by 4 hours (p less than 0.02) and returned to normal by 24 hours. There was no change in plasma of C3a desArg, C4a desArg, and C5a desArg (4 hours: mean C3a: 153.4 +/- 11.5 ng/ml versus 176.2 +/- 16.2 ng/ml for saline solution, p = ns; C4a: 159.6 +/- 32 ng/ml versus 151.4 +/- 21 ng/ml, p = ns; C5a: undetectable). To confirm the lack of C activation, we examined PMN chemotaxis (CTX) to C5a for any impairment caused by prior in vivo exposure to C5a. CTX to C5a was unaffected (4 hours: 109% +/- 22% of normal versus 114% +/- 10% for saline solution, p = ns). PMN CTX to formyl-methionyl-leucine-phenylalanine and PMN phagocytosis and killing of S. aureus were also unaffected by endotoxin. Thus, a single dose of endotoxin produced a subjective febrile illness and precipitated sustained PMN activation as indicated by increased PMN cell surface complement receptor number in the absence of C activation.     

Complement and endotoxin-induced lung injury in sheep

Intravenous infusions of endotoxin in sheep cause lung injury characterized by edema due to increased microvascular permeability. Similar increases in pulmonary microvascular permeability are seen in septic patients with the adult respiratory distress syndrome. Since endotoxin-induced lung injury may be mediated by interactions between products of complement activation and polymorphonuclear leukocytes, plasma and lung lymph from six unanesthetized sheep infused with Escherichia coli endotoxin (1.0 micrograms/kg over 30 min) were examined for complement-derived chemotactic activity. By 2-3 hr following infusion of endotoxin, all animals had the increased lung lymph fluid and protein flows characteristic of permeability edema. Preinfusion samples of plasma and lung lymph did not contain chemotactic activity for polymorphonuclear leukocytes. Following infusion of endotoxin, however, significant chemotactic activity was detected in plasma at 0.5-3.5 hr (P less than 0.05) and in lymph at 1.5-6.5 hr (P less than 0.025). The chemotactic activity was heat stable (56 degrees C for 30 min) but was abolished by treatment with antibodies to C5. These data indicate that infusions of endotoxin lead to the generation in plasma, and the appearance in lung lymph, of C5-derived peptides with chemotactic activity for polymorphonuclear leukocytes. C5-derived peptides may account for the pulmonary microvascular leukostasis and endothelial injury that lead to increased permeability edema after infusions of endotoxin.     

No benefit of reduced heparinization in thoracic aortic operation with heparin-coated bypass circuits

BACKGROUND: Heparin coating of the cardiopulmonary bypass circuit attenuates inflammatory response and confer clinical benefits in cardiac operations. The positive effects may be amplified with reduced systemic heparin dosage. We studied markers of inflammation and coagulation in thoracic aortic operations with heparin-coated circuits and standard vs reduced systemic heparinization. METHODS: Thirty patients were randomized to standard (group S; 300 IU/kg initially; activated clotting times [ACT] > 480 seconds; 5,000 IU in prime; n = 16) or reduced (group R; 100 IU/kg initially; ACT > 250 seconds; 2,500 IU in prime; n = 14) dose systemic heparin. The following markers were analyzed perioperatively: (a) inflammatory response; acute phase cytokine interleukin-6, and granulocytic proteins myeloperoxidase and lactoferrin; (b) complement activation; factor C3a and the C5a-9 terminal complement complex [TCC]; and (c) coagulation; thrombin-antithrombin III complex. RESULTS: The clinical outcome did not differ between groups. Four (29%) patients in group R had a perioperative thromboembolic event. All studied markers were significantly elevated during and throughout cardiopulmonary bypass in both groups. Maximal values were higher in group R for all variables except for TCC. There were no statistically significant intergroup differences regarding markers of inflammation, complement activation, or coagulation activation. CONCLUSIONS: The blood trauma in thoracic aortic operation is extensive, as reflected by the elevation of the studied biochemical markers, even when heparin-coated cardiopulmonary bypass circuits are used. In this study, we did not detect any benefits, either biochemical or clinical, of reducing the dose of systemic heparin.     

Isolated hyperthermic liver perfusion with cytostatic-containing perfusate activates the complement cascade.

Eight patients with advanced liver malignancy undergoing isolated hyperthermic liver perfusion with melphalan and cisplatin were studied with regard to complement activation and formation of anaphylatoxins (C3a and C5a) and terminal C5b-9 complement complexes (TCCs). Blood samples for complement variables (C1-INH, C3, C4, C5, C3a, C5a and TCCs) were taken before surgery, 1 min before the start of perfusion, 1, 2 and 3 h after the start of perfusion, and 24 h after operation. Samples were drawn from the perfusate 1 h after the start of perfusion. Activation of complement was observed during perfusion. Raised plasma concentrations of C3a and TCCs were recorded and high levels of C3a and TCCs were found in the perfusate. In vitro tests indicated that melphalan and cisplatin may activate complement. This activation occurred at 37 and 42 degrees C but was more pronounced at 42 degrees C.     

Does endotoxin-activated complement alter myocellular sodium homeostasis during sepsis?

BACKGROUND: Inappropriate complement activation is closely related to tissue injury and organ dysfunction during systemic infection. It is not clear, however, if endotoxin-induced complement activation is responsible for changes in myocellular sodium homeostasis during sepsis. METHODS: Rats underwent cecal ligation and puncture (CLP) or sham operation. Twenty-four hours after operation, fast-twitch extensor digitorum longus (EDL) muscles were isolated, incubated at 30 degrees C for 1 hour in Krebs-Henseleit buffer (KHB) (pH 7.4), and used to measure intracellular Na+ and K+ contents. Blood samples were collected to measure serum hemolytic complement activity and endotoxin levels. In addition, EDL muscles isolated from normal animals were incubated at 30 degrees C for 1 hour with zymosan-activated (10 mg/mL at 37 degrees C for 1 hour) rat sera, with lipopolysaccharide (LPS)-activated (LPS from Escherichia coli 055:B5, 10 or 200 microg/mL at 37 degrees C for 30 minutes) rat sera, with heat-inactivated (56 degrees C for 30 minutes) rat sera, with LPS (1 or 20 microg/mL), or in KHB. EDL muscles isolated from normal animals were also incubated with septic sera collected 6 or 24 hours after CLP with or without administration of soluble complement receptor type 1 (20 mg/kg, intraperitoneally). Myocellular Na+ and K+ contents ([Na+]i and [K+]i) were assayed using "washout" technique. Soluble C5b-9 complex levels in zymosan-activated or LPS-activated human sera were determined by enzyme-linked immunosorbent assay to evaluate the degree of complement activation induced by zymosan or LPS. RESULTS: Myocellular [Na+]i and [Na+]i/[K+]i ratios increased significantly 24 hours after CLP as compared with sham operation and were associated with decreased serum hemolytic complement activity and increased serum endotoxin levels. Zymosan-activated rat sera at sublytic concentrations markedly increased [Na+]i and [Na+]i/[K+]i ratios in isolated EDL muscles relative to heat-inactivated rat sera. LPS-activated rat sera, however, did not alter these two indices. In addition, myocellular [Na+]i and [Na+]i/[K+]i ratios were equivalent among normal EDL muscles incubated with septic sera, soluble complement receptor type 1-treated septic sera, or KHB. CONCLUSION: These results collectively suggest that polymicrobial sepsis, as produced by CLP, alters sodium homeostasis in fast-twitch skeletal muscles in association with changes in systemic complement activation and circulating endotoxin levels. Although endotoxin can activate the complement cascade, endotoxin-induced complement activation does not appear to be responsible for changes in myocellular sodium homeostasis observed during sepsis in rats.     

Changes in complement breakdown products and terminal complement complex in patients with acute glomerulonephritis

In this study we examined the role of the complement system in acute glomerulonephritis (AGN). Breakdown products of complements (iC3b, C4d and Bb) and Terminal complement complex (TCC, SC5b-9 complex) in plasma samples were measured by ELISA. The microassay plates were coated with monoclonal antibodies which bind specifically to human iC3b, C4d, Bb and SC5b-9 complex. This assay accurately quantitates small amounts of in vivo complement activation. The plasma samples were drawn from patients with AGN and other glomerulonephritis. There were some patients with various glomerulonephritis whose plasma iC3b, C4d and Bb concentrations were higher than those in normal human. However specificity was not found. The ratios iC3b/C3 and C4d/C4 were increased in the early stages of AGN, but plasma Bb concentrations revealed no significant changes. Plasma SC5b-9 complex concentrations were increased in the early stages of AGN. C3c, C3d, C4d and SC5b-9 were found to be localised in the glomeruli of those AGN patients. It is suggestive that in these cases of AGN (especially case 2) complement activation is predominantly mediated through the classical pathway and TCC is formed by this activation. This complement activation in the blood and the renal tissue is presumed to be involved in the initiation and progression of AGN.     

Complement activation and increased systemic and pulmonary vascular resistance indices during infusion of postoperatively drained untreated blood

In nine healthy young patients, operated on for thoracic scoliosis, a pulmonary artery catheter was inserted for the study of haemodynamic variables and blood sampling during autologous transfusion of postoperatively drained blood. At 1-3 h after wound closure, 10 ml kg/body weight of drained untreated blood from the wound was collected and recirculated over a l-h period. The concentration of the complement activation product, C3bc, increased from a mean of 5.4 (SD 1.5) AU ml-1 before infusion to 11.1 (3.9) AU ml-1 during infusion and then returned to 7.8 (2.8) AU ml-1 after infusion. The concentration of the terminal complement complex (TCC) increased from 0.5 (0.2) to 1.3 (0.5) AU ml-1 and was reduced to 0.7 (0.3) AU ml-1 after infusion. Only TCC exceeded the reference values which are 14 AU ml-1 for C3bc and 1.0 AU ml-1 for TCC. Pulmonary vascular resistance index concomitantly increased from a mean of 130 (SD 52) to 195 (88) dyn s cm-5 m-2 and was reduced to 170 (86) dyn s cm-5 m-2 after infusion. Systemic vascular resistance index increased from a mean of 1238 (SD 403) to 1349 (473) dyn s cm-5 m-2 and returned to 1196 (401) dyn s cm-5 m-2 after infusion. White blood cell count (WCC) increased from 14.4 (4.3) x 10(9) litre-1 before infusion to 17.8 (7.2) x 10(9) litre-1 during and after infusion. No change in platelet count during infusion was observed. There were no differences in WCC or platelet count between mixed venous or peripheral arterial blood. Pulmonary and systemic vascular resistance indices may be influenced by activated complement in drained untreated blood when it is recirculated.      

Complement activation, endothelin-1 and neuropeptide Y in relation to the cardiovascular response to endotoxin-induced systemic inflammation in healthy volunteers

BACKGROUND: Endotoxin is a major stimulus for triggering the host response in septicaemia. The pathophysiology of sepsis involves activation of the vascular endothelium and leukocytes, resulting in the release of various mediators, e.g. cytokines, nitric oxide (NO), endothelin (ET-1) and complement factors. We evaluated the blood levels of complement activation, ET-1 and neuropeptide Y (NPY) in parallel with the haemodynamic and oxygen transport response during human experimental endotoxemia. METHODS: Eleven healthy men had venous, arterial and pulmonary arterial catheters placed for continuous haemodynamic measuring. After 30 min rest endotoxin (E. Coli 4 ng kg(-1), Lot G1) was intravenously administered. Blood samples from pulmonary and arterial catheters were collected hourly over 4 h. RESULTS: Body temperature augmented significantly from baseline values (36.7 +/- 0.7 degrees C, mean +/- SEM) with a maximum after 3.5 h (39.1 +/- 0.3 degrees C, P < 0.001). Cardiac output increased by 100%, systemic vascular resistance decreased by 50%, the oxygen consumption and the tissue oxygen transport increased. Activation of the complement system was indicated by an increase in SC5b-9. Endothelin-1-like immunoreactivity (ET-1-LI) increased over time in arterial blood. NPY-like immunoreactivity (NPY-LI) did not change over time. CONCLUSION: A dose of endotoxin associated with reproducible systemic vasodilation and fever in healthy subjects causes complement activation and increased systemic levels of ET-1-LI, illustrating that the model is a useful tool for inducing moderate systemic inflammation where several mediator systems are activated.     

Complement inhibition by FUT-175 and K76-COOH in a pig-to-human lung xenotransplant model

Abstract: Two complement inhibitors, FUT-175 (FUT) and K76-COOH (K76), were studied as single agents in an ex vivo, in situ model of pig lung rejection by human blood. Pulmonary toxicity (primarily increased pulmonary vascular resistance [PVR]) was seen with FUT at a dose which inhibited complement in vitro (0.4 mg/ml); a lower dose (0.1 mg/ml) was therefore used. K76 had little apparent toxicity at a dose which inhibited complement in vitro (6 mg/ml), but activated complement, leading to C3a elaboration. Efficacy was then assessed by 1) deposition of complement pathway components in the lung and 2) lung survival during perfusion with human blood. Neither agent consistently prolonged median lung survival (FUT: 50 min.±8 SEM; K76: 37±6), blocked thromboxane production, or prevented PVR elevation compared to experiments using unmodified human blood (survival 9 min.±2). At the doses used, both agents prevented deposition of terminal complement complex (TCC) in the lung. This finding demonstrates that the various phenomena associated with hyperacute lung rejection (thromboxane release, PVR elevation, capillary leak, and intraalveolar hemorrhage) can all occur despite abrogation of membrane attack complex formation. We can not exclude a contribution by drug toxicity or complement damage (mediated by C3a or other complement pathway components proximal to TCC) to the observed lung injury. We conclude that, although both FUT and K76 inhibit deposition of TCC in the lung, at the dose tested neither drug is useful as a single agent to prolong survival in a pig-to-human lung xenograft model.     

Diversity of complement activation by lentinan, an antitumor polysaccharide, in gastric cancer patients

Lentinan, a pure polysaccharide, augments many immune responses in vivo but not in vitro. Therefore reaction with any factor is thought to be required for triggering of immunopotentiation by lentinan. To clarify the role of complement in this effect, we investigated whether lentinan could activate alternative pathway of complement or not and the relation with the immunopotentiation in 13 gastric cancer patients. C3, C3a, C5 and C5a levels as parameters of complement activation and interleukin-2 producing activity as parameter of immunopotentiation were assayed before and immediately after intravenous injection of lentinan. Among these complement components, remarkable change was observed only in C3a level. C3a level elevated to more than 1000ng/ml from less than 300ng/ml. And according to the degree and continuation of the elevation, these patients were classified into 3 types-(1) every time little elevation, (2) first remarkable and thereafter little elevation and (3) continuous remarkable elevation. Such an elevated C3a level returned to the level before lentinan injection within one day. When C3a level elevated to more than 1000ng/ml, leukocyte counts of peripheral blood decreased significantly and interleukin-2 producing activity increased concomitantly. Thus, there was diversity in response to lentinan and complement activation was suggested to have contribution in immunopotentiation by lentinan.