Effects of a cytokine inhibitor, JTE-607, on the response to endotoxin in healthy human volunteers.

It is generally regarded that the excessive production of cytokines plays an important role in the pathology of autoimmune diseases and septic shock. We have investigated the ability of JTE-607, a novel inhibitor of cytokine production, to modulate the inflammatory response to endotoxin in healthy human volunteers. Three cohorts of healthy male volunteers were recruited for a randomized, placebo-controlled, double-blind study. Within each cohort, 6 subjects received a single 8-hour intravenous infusion of JTE-607 (either 0.03, 0.1 or 0.3 mg/kg/h) and 3 subjects received a placebo infusion. Two hours after the start of the JTE-607 infusion, all subjects received a 30 unit/kg bolus infusion of endotoxin. JTE-607 administration resulted in the decrease in endotoxin-induced IL-10 production with mean % difference from placebo of -79.5% (P=0.040) and -86.2% (P=0.026) at 0.1 and 0.3 mg/kg/h dose, respectively. The production of endotoxin-mediated interleukin (IL)-1 receptor antagonist was significantly inhibited at 0.3 mg/kg/h dose with mean % difference from placebo of -60% (P=0.0037). Endotoxin-induced C-reactive protein decreased with the increasing dose of JTE-607 with mean % difference from placebo of -32.1% (P=0.322), -82.9% (P=0.0001) and -90.3% (P<0.0001) at 0.03, 0.1 and 0.3 mg/kg/h dose, respectively. In conclusion, this study describes a cytokine modulator JTE-607, which inhibits production of IL-10, IL-1ra and C-reactive protein in a human model of endotoxemia.

The role of cytokines as biomarkers in systemic lupus erythematosus and lupus nephritis.

Cytokines play an important role in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis. This is currently a very active area of research. Of particular interest is the use of cytokines as biomarkers of disease activity in SLE and lupus nephritis. Can cytokine measurements assist in early detection of renal flare in known lupus nephritis? Can such measurements be used to distinguish between flare and chronic damage? Or help to confirm renal remission? Could they be used to help assess the required duration of immunosuppression and reduce the need for invasive renal biopsy? This review discusses limitations of current laboratory methods in monitoring SLE, how measurements of cytokines may contribute in relation to following disease activity and summarizes what is known about cytokines as biomarkers in SLE and lupus nephritis.

Changes in HLA-DR expression, cytokine production and coagulation following endotoxin infusion in healthy human volunteers.

The infusion of a low dose of endotoxin into healthy subjects triggers a complex inflammatory response but the intricacies of which, despite extensive research, are still being unraveled. Nine healthy male volunteers received a dose of 30 Units endotoxin/kg bodyweight as an intravenous bolus. Following endotoxin infusion the concentration of TNF-alpha in their serum rapidly increased within 30 min, peaked after 1-2 h and returned to baseline by 4 h. This corresponded to a similarly rapid increase in anti-inflammatory soluble TNF receptor (sTNFR) levels, which remained elevated for up to 48 h. Increased levels of other cytokines were measured, including IL-6, IL-8, G-CSF, IL-1ra and IL-10. However, these cytokines lagged behind that of TNF-alpha and remained elevated for up to 8 h. Endotoxin injection resulted in complex changes in HLA-DR expression, a marker of monocyte activation state. Initially, following a lag of 2-4 h, HLA-DR expression decreased with a nadir at 8 h, followed by an increase in expression above baseline at 22 h. HLA-DR levels returned to baseline 48 h post-endotoxin challenge. This was in contrast to endotoxin-induced changes in white blood cell (WBC) numbers, which dropped rapidly (at 2-3 h) while HLA-DR levels were stable and then peaked during the nadir in HLA-DR expression (8 h). Furthermore, endotoxin injection caused activation of both fibrinolytic and coagulation pathways. Thus, endotoxin infusion results in complex changes in HLA-DR expression, production of pro- and anti-inflammatory cytokines and activation of coagulation.

Use of proteomics to discover novel markers of cardiac allograft rejection.

Endomyocardial biopsy remains the most reliable method of detecting rejection following cardiac transplantation. Despite numerous attempts to detect rejection using a blood assay, none have proved reliable enough to replace the biopsy. Here, we have investigated the hypothesis that proteomics has the potential to reveal many molecules which are upregulated in the heart during rejection, some of which may serve as novel blood markers of rejection. Initially, sequential cardiac biopsies (33 in total) from 4 patients were analysed by two-dimensional gel electrophoresis according to whether they showed rejection (n = 16) or no rejection (n = 17); over 100 proteins were found to be upregulated by between 2- and 50-fold during rejection. Of these, 13 were identified and were found to be cardiac specific or heat shock proteins. Two of these (alphaB-crystallin, tropomyosin) were measured by ELISA in the sera of 17 patients followed for 3 months after their transplants. Mean levels of alphaB-crystallin and tropomyosin were significantly higher in sera associated with biopsies showing 1A (p = 0.007) or all grades of rejection (p = 0.022) compared to no rejection. These studies demonstrate that proteomics is a powerful method that can be used to identify novel serum markers of human cardiac allograft rejection.