Both C3a and C3a(desArg) regulate interleukin-6 synthesis in human peripheral blood mononuclear cells.

Synthesis of complement components is part of the acute-phase response. Interleukin-6 (IL-6) is a critical mediator of the acute-phase response during infections and injuries. Plasma levels of C3a and IL-6 have been proposed as prognostic indicators in sepsis and trauma. The effects of C3a and C3a(des)Arg on IL-6 gene expression and protein production in human peripheral blood mononuclear cells (PBMC) were investigated. Neither C3a nor C3a(des)Arg alone induced detectable IL-6 protein or mRNA levels. However, C3a and C3a(des)Arg affected endotoxin-induced IL-6 synthesis in a dose-dependent manner. In nonadherent PBMC, C3a or C3a(des)Arg suppressed, while in adherent PBMC, C3a or C3a(des)Arg enhanced IL-6 protein and mRNA levels. These results suggest that C3a and C3a(des)Arg may provide a control mechanism of acute-phase responses by enhancing IL-6 synthesis in adherent monocytes at local inflammatory sites and by inhibiting IL-6 synthesis in circulating monocytes.

Interaction with autologous platelets multiplies interleukin-1 and tumor necrosis factor production in mononuclear cells.

The effect of activated platelets on cytokine production by human peripheral blood mononuclear cells (PBMC) was investigated. When PBMC were coincubated with activated autologous platelets amid lipopolysaccharide (LPS, 50-100 pg/mL) for 8 h, the production of interleukin (IL)-1alpha increased 11- to 18-fold and tumor necrosis factor (TNF)-alpha 3- to 5-fold compared with PBMC without platelets. Activated platelets in a dual-chamber well that prevented platelet-PBMC contact but permitted passage of soluble factors enhanced IL-1alpha production (P < .01). Platelet-PBMC contact in the chamber resulted in a further enhancement of IL-1alpha production. These data suggest that platelet-PBMC interaction, both directly and with platelet-derived factors, enhances production of shock-producing IL-1alpha and TNF-alpha, albeit differently. The interaction of platelets with monocytes may play an important role in the pathophysiology of sepsis and disseminated intravascular coagulation.

Health effects of salicylates in foods and drugs.

There is much (renewed) interest about the effects of salicylates on food intolerance, attention-deficit disorders, and cardiovascular disease. Current evidence for the efficacy of salicylate-elimination diets in the treatment of attention-deficit disorders and hyperactivity is weak, and further investigation is required on the relationship between salicylates and cardiovascular disease.

A new biologic role for C3a and C3a desArg: regulation of TNF-alpha and IL-1 beta synthesis.

The complement activation products C3a and C3a desArg are generated in the course of trauma, infection, tissue injury, and ischemia. We have investigated the effects of C3a and C3a desArg on gene expression and protein synthesis of TNF-alpha and IL-1 beta in PBMC. Neither C3a nor C3a desArg alone induced detectable protein or mRNA levels for TNF-alpha and IL-1 beta. C3a modulated LPS-induced TNF-alpha and IL-1 beta synthesis. In nonadherent PBMC, C3a suppressed LPS-induced synthesis of TNF-alpha (20-71% decrease by 0.2-10 microgram/ml of C3a, p less than 0.01) and IL-1 beta (19-57% decrease by 0.5-10 microgram/ml of C3a, p less than 0.01), independently of endogenous production of PGE2. C3a also suppressed LPS-induced mRNA levels for TNF-alpha and IL-1 beta. In contrast, in adherent PBMC, C3a at 5 to 20 microgram/ml enhanced LPS-induced TNF-alpha (75-188% increase, p less than 0.001) and IL-1 beta (119-274% increase, p less than 0.001) synthesis. C3a enhanced TNF-alpha and IL-1 beta mRNA levels in LPS-stimulated adherent cells. Furthermore, C3a desArg shared with C3a the ability to modulate LPS-induced mRNA and protein synthesis for TNF-alpha and IL-1 beta. These results suggest that C3a, thought to be proinflammatory, and C3a desArg, thought to be biologically inactive, are modulators of inflammation. Both C3a and C3a desArg may enhance cytokine synthesis by adherent monocytes at local inflammatory sites, while inhibiting the systemic synthesis of proinflammatory cytokines by circulating cells.

Alkylation of cellulosic membranes results in reduced complement activation.

4-Vinyl pyridine was grafted to the surface of the cellulosic membrane Cuprophan, and subsequently alkylated with both C10 and C16 aliphatic chains. Complement activation of heparinized human blood, corrected for anaphylatoxin adhesion, was measured by radioimmunoassay. The surface treatments both yielded substantial reductions in C5a activity, with a lessor reduction in C3a and C4a activity. Alkylation with 10 and 16 carbon chains resulted both in enhancements of albumin adsorption and stability. These enhancements as well as the reductions in complement activation were statistically indistinguishable between the two treatments. The reduction in complement activation was influenced more by adsorption of endogenous albumin and possibly by the vinyl pyridine graft, than the removal of surface active hydroxyl groups from Cuprophan.

Effects of malignancy and interleukin-2 infusion on gut macromolecular permeability.

OBJECTIVE: Enhanced gut permeability has been shown in patients with advanced malignancy. The dramatic inflammatory shock syndrome produced by high-dose interleukin-2 immune therapy could further change gut barrier function. This study measured the effect of advanced renal cell carcinoma and malignant melanoma, and interleukin-2 treatment on gut permeability. DESIGN: Nonrandomized, controlled study. SETTING: University hospital. PATIENTS: Adults with metastatic, unresectable renal cell carcinoma or metastatic, malignant melanoma, and normal volunteers. INTERVENTIONS: Gut permeability was measured in patients with renal cell carcinoma or malignant melanoma before and during interleukin-2 infusions, using polyethylene glycol 3350 and polyethylene glycol 400. The polyethylene glycols were administered orally within 48 hrs of interleukin-2 therapy and the 24-hr urine excretions were measured. MEASUREMENTS AND MAIN RESULTS: Increased permeability was seen in the baseline state of these patients (ratio of polyethylene glycol 3350 to polyethylene glycol 400 = 1.1 +/- 0.7 x 10(-2)) when compared with normal volunteers (ratio = 0.48 +/- 0.2 x 10(-2); p < .05). However, after interleukin-2 treatment, no further increase in permeability was seen (ratio = 1.4 +/- 0.8 x 10(-2)). CONCLUSIONS: Gut permeability to polyethylene glycol 3350 is enhanced in advanced malignancy. High-dose interleukin-2 therapy does not further increase permeability of the gut.

Coagulation of whole blood stimulates interleukin-1 beta gene expression.

To study interleukin (IL)-1 beta gene expression, reverse transcription-polymerase chain reaction was used on 25-microL whole blood samples from 11 healthy subjects. Coagulated and unclotted whole blood was compared. There was no evidence of IL-1 beta gene expression in any time zero samples (i.e., whole blood from which mRNA was immediately extracted) from 11 subjects, whereas a 388-bp band representing IL-1 beta mRNA was detected in all coagulated samples. No mRNA for IL-1 beta was detected in EDTA-anticoagulated whole blood, although in these samples the addition of lipopolysaccharide as a positive control induced the expression of IL-1 beta. In time course studies on samples allowed to clot, mRNA for IL-1 beta was detectable after 30 min. These findings demonstrate that IL-1 beta gene expression is not present in circulating cells of healthy subjects and that coagulation is a stimulus for IL-1 beta gene expression. This may be a mechanism by which thrombosis produces inflammation and fever.

The immune response to trauma.

The response to trauma begins in the immune system at the moment of injury. The loci are the wound, with activation of macrophages and production of proinflammatory mediators, and the microcirculation with activation of endothelial cells, blood elements, and a capillary leak. These processes are potentiated by ischemia and impaired oxygen delivery and by the presence of necrotic tissue, each exacerbating the inflammatory response. Hemorrhage alone may be a sufficient stimulus. Inflammation once was considered to be a host reaction to bacteria or other irritants. This concept was expanded by the discovery of autoimmune diseases, and we are now aware that some illnesses are the result of the body's response to an invader rather than the direct effect of the invader itself. The discoveries about the response to trauma described here add another dimension, showing inflammation to be a fundamental life process that begins at the molecular level at the moment of injury and that, depending on the severity of the stimulus and the effectiveness of initial treatment, may spread to include every cell, tissue, and organ in the body, for good or ill. An important part of these expanding concepts is the notion that all noxious stimuli activate the cytokine system as a final common pathway. Sepsis, hemorrhage, ischemia, ischemia-reperfusion, and soft tissue trauma all share an ability to activate macrophages and produce proinflammatory cytokines that may initiate the SIRS. Second-message compounds and effector molecules mediate the observed clinical phenomena.(ABSTRACT TRUNCATED AT 250 WORDS)

Methotrexate treatment of idiopathic granulomatous hepatitis.

OBJECTIVE: To test the efficacy and safety of low-dose oral pulse methotrexate therapy in patients with idiopathic granulomatous hepatitis who had complications of, did not respond to, or refused glucocorticoid therapy. DESIGN: Prospective case study. SETTING: Academic medical center hospital. PATIENTS: Seven patients with biopsy-proven, idiopathic granulomatous hepatitis who could not tolerate or were unresponsive to glucocorticoid therapy. INTERVENTION: Low-dose oral pulse methotrexate, 15 mg/wk. MEASUREMENTS: Temperature, symptoms, dose of concurrent glucocorticoids, biochemical tests of liver function, side effects of methotrexate, and assessment of liver biopsy specimens. RESULTS: All six febrile patients became afebrile within 3 months of starting methotrexate. Fatigue and anorexia improved in all patients. Glucocorticoid therapy was successfully discontinued within 6 months of starting methotrexate in four patients receiving prednisone at entry. Liver biopsy specimens were obtained again after methotrexate therapy and showed absence of granulomas in four of four patients. The minimum effective dose of methotrexate was 0.20 mg/kg body weight per week. No serious adverse effects and no failures to respond to methotrexate therapy were noted in this group of patients. In three patients, methotrexate therapy has been successfully tapered without signs or symptoms of recurrent disease. CONCLUSIONS: Low-dose oral pulse methotrexate was effective in treating patients with granulomatous hepatitis.

Platelet activating factor-antagonist improves survival in experimental staphylococcal septicemia.

Platelet activating factor (PAF) amplifies the cytokine cascade in experimental models. This study was designed to investigate the role of PAF blockade during experimental Gram-positive shock by pretreatment with platelet activating factor-antagonist (PAF-A). Three groups of anesthetized rabbits were studied. Control animals received either saline or PAF-A only, and all survived, without hemodynamic changes. Animals in the second group received an infusion of Staphylococcus epidermidis, and all died in septic shock. Animals in the third group were pretreated with PAF-A and given the staphylococcal infusion; five of the six were alive at 200 minutes, with near-normal hemodynamics. The survival rate for animals pretreated with PAF-A was significantly higher than that for animals receiving staphylococci alone (P < .02). These results suggest that PAF is an important mediator of Gram-positive sepsis. Antagonism of PAF may be an effective potential therapy for sepsis.

Altered interleukin-1 and tumor necrosis factor production and secretion during pyrogenic tolerance to LPS in rabbits.

Rabbits were injected intravenously with 10 micrograms/kg of endotoxin [lipopolysaccharide (LPS)] on days 0, 1, and 7, and rectal temperatures were monitored. The febrile responses were compared with circulating levels of interleukin-1 beta (IL-1 beta) and tumor necrosis factor (TNF) and in vitro synthesis of these cytokines by peripheral blood mononuclear cells (PBMC) isolated just before the injection of LPS. Fever after the first LPS injection was biphasic on day 0, attenuated and monophasic after the second LPS injection on day 1, and augmented after third injection of LPS on day 7. On day 1, circulating TNF and IL-1 beta levels were significantly (P < 0.05) decreased compared with those on days 0 and 7. Similarly, TNF and IL-1 beta synthesis by LPS-stimulated PBMC were significantly reduced on day 1. On day 7, cellular synthesis and secretion of IL-1 beta were significantly increased compared with that on day 0. A significant positive correlation was observed between fever index and total in vitro IL-1 beta synthesis by LPS-stimulated PBMC (r = 0.866, P = 0.001). These data demonstrate that pyrogenic tolerance in the rabbit after a single LPS injection is associated with decreased circulating IL-1 beta and TNF levels as well as decreased production of these cytokines in vitro. In addition, the pyrogenic hyperresponsiveness to LPS after 7 days is associated with increased synthesis and secretion of IL-1 beta from PBMC in vitro.

Acute respiratory failure in patients treated for babesiosis.

Babesiosis is a tick-borne protozoal disease with infrequent clinical complications. We report three cases of noncardiogenic pulmonary edema in patients from Nantucket Island, MA, with a history of Lyme disease and review the clinical presentation of babesiosis and its treatment. Respiratory complications in our patients, as well as in the four previously reported cases in the literature, occurred a few days after initiation of medical therapy. We hypothesize that the pathophysiology of the pulmonary edema is multifactorial, due to decreased deformability of the infected erythrocytes, increased cytoadherence of red blood cells in capillaries and venules, and a possible role of excessive production of certain cytokines, such as tumor necrosis factor and interleukin-1.

Thermal injury induces very early production of interleukin-1 alpha in the rat by mechanisms other than endotoxemia.

BACKGROUND: Cytokines are putative mediators of thermal injury-induced systemic changes. We studied the effects of thermal injury on cytokine activation in vivo with a sensitive radioimmunoassay specific for rat interleukin-1 alpha (IL-1 alpha). METHODS: We characterized the organ distribution and expression kinetics of IL-1 alpha in rats submitted to either 20% total body surface area cutaneous burn, muscle burn, or endotoxic shock. Rats were killed at various time points, and liver, lung, spleen, ileum, thymus, kidney, skin, and plasma were harvested. Tissues were homogenized, and the supernates were assayed for rat IL-1 alpha. The assay detection limit was 1.5 ng/gm wet tissue (WT). RESULTS: Thermal injury induced marked elevations of IL-1 alpha levels in the liver and lung, and maximal levels were reached at 2.5 hours when compared with controls. In the liver mean IL-1 alpha levels in cutaneous burn injury were 16.5 +/- 6.2 ng/gm WT, whereas in sham injury they were 1.7 +/- 0.1 ng/gm WT, p < or = 0.05; in the lung IL-1 alpha levels with cutaneous burn injury were 10.3 +/- 1.3 ng/gm WT, whereas sham injury levels were 1.9 +/- 0.8 ng/gm WT, p < or = 0.002). Levels in all other organs and plasma were below detection limits. Muscle burn injury had similar elevated levels of IL-1 alpha in the liver at 1 hour, indistinguishable from cutaneous burn. In contrast, endotoxin challenge resulted in dramatic elevation of IL-1 alpha levels in all organs tested except for the kidney, whereas the skin maintained its usual large amounts of IL-1 alpha. CONCLUSIONS: These data indicate that thermal or mechanical injury induce very early and organ-specific association of IL-1 alpha in vivo by mechanisms other than endotoxemia.

Interleukin-1 (IL-1) receptor antagonist prevents Staphylococcus epidermidis-induced hypotension and reduces circulating levels of tumor necrosis factor and IL-1 beta in rabbits.

Similar to shock in gram-negative sepsis, shock from gram-positive organisms is mediated, in part, by tumor necrosis factor (TNF) and interleukin-1 (IL-1). In the present study, rabbits were infused with IL-1 receptor antagonist (IL-1ra) prior to and during Staphylococcus epidermidis-induced hypotension. After injection of bacteria, a maximal fall in mean arterial pressure to -42% below baseline occurred at 200 min in vehicle-treated animals compared with a nonsignificant decrease of only 7% in the IL-1ra-treated group (P < 0.01, vehicle versus IL-1ra). A similar attenuation was observed in the fall in systemic vascular resistance (P < 0.05). After the injection of S. epidermidis, TNF levels rose to a peak elevation of 475 +/- 160 U/ml in vehicle-treated rabbits, but in rabbits receiving IL-1ra, maximal TNF levels rose only to 85 +/- 23 U/ml (P < 0.01). Plasma IL-1 beta reached maximal concentrations at 180 min of 364 +/- 71 pg/ml in vehicle-treated animals but only 145 +/- 12 pg/ml in rabbits given IL-1ra (P < 0.05). The reductions in TNF and IL-1 were not due to interference by IL-1ra in the respective assays. In vitro, IL-1ra inhibited S. epidermidis-induced TNF from mononuclear cells by 31% +/- 11%, from spleen cells by 17% +/- 4% (P < 0.05), and from whole blood by 42% +/- 17%. Despite the near reversal of the fall in mean arterial pressure and systemic vascular resistance in IL-1ra-treated rabbits, leukopenia and thrombocytopenia were unaffected. These results demonstrate that IL-1ra blocks shock-like hemodynamic parameters and reduces circulating IL-1 and TNF levels in a model of gram-positive sepsis.

Intestinal production of interleukin-1 alpha during endotoxemia in the mouse.

Interleukin-1 (IL-1) may be involved in gut permeability to macromolecules and gut glutamine metabolism during endotoxemia. We developed a sensitive radioimmunoassay specific for mouse IL-1 alpha (detection limit of 100 pg/ml, or 5 pM) and measured intestinal levels of IL-1 alpha in response to endotoxin. CD-1 mice (N = 190) were randomized to intraperitoneal (ip) or intravenous (i.v.) lipopolysaccharide (LPS) infusion (15 micrograms/g or 1.5 micrograms/g Escherichia coli 0111:B4 LPS) or saline. Mice were sacrificed at Time 0, 30 min, 1 hr, 2.5 hr, 4 hr, 6 hr, 12 hr, and 24 hr (3 mice/group/time point). Small bowel (SB) and large bowel (LB) were harvested and compared to liver. Duodenum, upper jejunum, midjejunum, terminal ileum, cecum, ascending colon, and sigmoid were analyzed in separate experiments. Tissues were frozen, weighed, and homogenized, the homogenates were centrifuged, and the supernates were assayed for immunoreactive IL-1 alpha. IL-1 alpha was expressed as pg/g wt +/- SEM (lowest detectable amount = 1000 pg/g wet tissue (WT)). SB but not LB from normal controls had constitutively elevated levels of IL-1 alpha (6177 +/- 1640 pg/g WT). LPS ip or i.v. produced lethargy, diarrhea, and a dramatic elevation of IL-1 alpha levels in both SB and LB. In SB, IL-1 alpha was elevated compared to baseline at 1 hr (19201 +/- 626 pg/g WT) and reached a fivefold maximal increase at 2.5 hr (31775 +/- 503 pg/g WT) following 15 micrograms/g ip.(ABSTRACT TRUNCATED AT 250 WORDS)

Activated platelets induce endothelial secretion of interleukin-8 in vitro via an interleukin-1-mediated event.

Migration of neutrophils through endothelial cells (EC) and induction of cytokine secretion are two well-documented events during the inflammatory reaction. The inflammatory, chemotactic cytokine interleukin-8 (IL-8) is secreted by EC in response to IL-1 stimulation. In this study, we show that platelets activated with either adenosine-5'-diphosphate or epinephrine induce IL-8 secretion by EC. This stimulatory activity was found to be associated with sedimented platelets after activation. Blockade of IL-1 receptors on EC with IL-1 receptor antagonist (IL-1Ra) decreased the stimulatory effect of whole activated platelet preparations by 59% (P < .05). Similarly, IL-1Ra pretreatment of EC reduced the stimulatory effect of sedimented activated platelets by 60% (P < .01). In addition, we treated human blood donors with 750 mg of oral aspirin, and evaluated the stimulatory effect of epinephrine-activated platelets on IL-8 secretion by EC. IL-8 synthesis after aspirin ingestion was inhibited by 90% (P < .01) as compared with the preaspirin stimulation. These observations show that activated platelets induce IL-8 secretion via membrane-associated IL-1 activity, and provide a novel relationship between coagulation and inflammation that could be relevant to several diseases.