High-dose infusion of IgG (IVIG) is used to treat autoimmune and inflammatory diseases, including Kawasaki disease (KD). Although the immunomodulatory effects of IVIG on blood cells such as macrophages have been well studied, its effects on tissue cells remain unclear. Here, we show that high-dose IgG specifically and completely inhibited TNF-α-induced, but not IL-1β-induced, secretion of proinflammatory cytokines such as G-CSF and IL-6 by cultured human coronary artery endothelial cells (HCAECs). Highdose IgG did not inhibit TNF-α-mediated early signaling events of the NF-κB and MAPK pathways but it potently inhibited gene expression of G-CSF and IL-6 12 h after TNF-α-stimulation. Interestingly, suppression of the G-CSF and IL-6 gene expression correlated closely with functional inhibition of a transcription factor, C/EBPδ, whose binding sites in the promoters of G-CSF and IL-6 have been shown to be critical for their transcriptional activation. Furthermore, the inhibitory effect of intact IgG on HCAECs was exerted mainly via its F(ab') 2 fragment, and not its Fc fragment. These findings suggest that the clinical effects of IVIG on KD patients are at least in part due to its direct anti-inflammatory effects on the coronary endothelium, which is a major lesion site in the pathogenesis of KD. Keywords:Coronary artery endothelial cells r IVIG r Kawasaki disease r TNF-α Supporting Information available online IntroductionIntravenous infusion of IgG was originally used as a replacement therapy for patients with hypogammaglobulinemia in the Correspondence: Dr. Akio Matsuda e-mail: amatsuda@nch.go.jp early 1950s. High-dose infusion of IgG (IVIG) is now used to treat autoimmune and inflammatory diseases such as idiopathic thrombocytopenic purpura, Guillain-Barre syndrome, and Kawasaki disease (KD). To date, a number of possible mechanisms for the immunomodulatory and anti-inflammatory effects of IVIG therapy have been described [1,2] KD is an acute systemic vasculitis seen in infants and young children [9,10], and it is frequently associated with coronary artery aneurysms [11]. IVIG is a well-established standard therapy for KD that effectively reduces systemic inflammation and the incidence of coronary artery lesions (CALs) [12][13][14]. The clinical evidence strongly suggests that IVIG exerts its beneficial effects by attenuating coronary artery inflammation. However, the mechanisms underlying these clinical effects of IVIG on coronary endothelium are not well understood, and some patients do not respond to IVIG and develop CALs. Thus, we examined the in vitro effects of high-dose IgG on cultured human coronary artery endothelial cells (HCAECs), which is a major lesion site in the pathogenesis of KD.We used TNF-α as an inflammatory stimulus in most of our in vitro experiments for the following reasons. First, during the acute phase of KD, serum levels of TNF-α are significantly elevated and correlate with the incidence of CALs in acute KD patients [15,16]. Second, TNF-α was shown to be necessary for induction of coro...

Plasma fibronectin (FN) has a broad range of biological functions involved in cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing, reticuloendothelial system function, and ischemic injury. In this study, we examined the effects of FN on D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant liver failure in mice. Female Balb/c mice received intraperitoneal injection of 50 mg/kg of LPS and 400 mg/kg of GalN simultaneously. Thirty minutes before GalN/LPS administration, human plasma FN (FN group) or the same dose of human serum albumin (control group) was given intravenously. GalN/LPS induced a marked decrease in plasma FN, which was reversed by FN pretreatment. The survival rate of the FN group was markedly improved in a dose-dependent manner compared with that of the control group (survival rate 0%). FN prevented increases in the concentrations of serum enzymes and total bilirubin related to liver injury. FN pretreatment significantly suppressed tumor necrosis factor (TNF)-a, interferon (IFN)-g, and interleukin (IL)-6 levels, and enhanced IL-10 levels in serum and liver tissue compared with the control group. Moreover, TUNEL staining, caspase 3 and 8 activities, and necrosis in the remnant liver were significantly decreased in the FN-treated rats compared with the controls. Furthermore, FN pretreatment inhibited the activation of nuclear factor (NF)-kB and increased the expression of Bcl-xL protein in liver tissue. These results suggest that FN protected against GalN/LPSinduced liver failure by a mechanism involving inhibition of NF-kB activation, which caused down-regulation of TNF-a and involved up-regulation of IL-10, and elevation of Bcl-xL induced a blockage of apoptotic signals, by which apoptosis of hepatocytes caused by GalN/LPS was suppressed.

A method for the heat treatment of human IgG solution at 60 °C for 10 h was established. Human immunodeficiency, mumps, vaccinia and 4 other viruses were added to the IgG solution in 33% sorbitol and heated at 60 °C. Those viruses were inactivated within 1 h. Heat-treated intravenous IgG (IVIG-H) was prepared by heat treatment and polyethylene glycol (PEG) fractionation. Conventional nonheated intravenous IgG (IVIG-C) was prepared from the same source paste by the fractionation method. No physicochemical or biological difference was observed between the heated and control IVIG preparations.

A method for the heat treatment of human IgG solution at 60 degrees C for 10 h was established. Human immunodeficiency, mumps, vaccinia and 4 other viruses were added to the IgG solution in 33% sorbitol and heated at 60 degrees C. Those viruses were inactivated within 1 h. Heat-treated intravenous IgG (IVIG-H) was prepared by heat treatment and polyethylene glycol (PEG) fractionation. Conventional nonheated intravenous IgG (IVIG-C) was prepared from the same source paste by the fractionation method. No physicochemical or biological difference was observed between the heated and control IVIG preparations.

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