Inhibition of CXCL10 release by monomeric C3bi and C4b.

Cellulose acetate (CA) beads are often used for leucocyte apheresis therapy against inflammatory bowel disease. In order to clarify the mechanism of the anti-inflammatory effects of CA, global analysis of the molecules generated in blood by the interaction with CA beads was performed in this study. An activated medium was collected from whole blood that had been preincubated with CA beads, and the effects of the CA-activated medium on leucocyte function were investigated. Fresh blood was stimulated with lipopolysaccharide (LPS) or interferon (IFN)-ß in the presence of the activated medium, and levels of chemokines and cytokines, including CXCL10 (IFN-inducible protein-10), and phosphorylated STAT1 (signal transducer and activator of transcription 1), which is known to be essential for CXCL10 production in leucocytes, were measured. IFN-ß- or LPS-induced CXCL10 production, expression of CXCL10 mRNA and phosphorylation of STAT1 were significantly reduced in the presence of the medium pretreated with CA beads compared with the control without the CA bead treatment. The factors inhibiting CXCL10 production were identified as the C3 and C4 fragments by mass spectrometry. The monomeric C3bi and C4b proteins were abundant in the medium pretreated with CA beads. Furthermore, purified C3bi and C4b were found to inhibit IFN-ß-induced CXCL10 production and STAT1 phosphorylation. Thus, STAT1-mediated CXCL10 production induced by stimulation with LPS or IFN was potently inhibited by monomeric C3bi and C4b generated by the interaction of blood with CA beads. These mechanisms mediated by monomeric C3bi and C4b may be involved in the anti-inflammatory effects of CA.

Skew in T cell receptor usage with polyclonal expansion in lesions of oral lichen planus without hepatitis C virus infection.

Oral lichen planus (OLP) is a refractory disorder of the oral mucosa. Its predominant symptoms are pain and haphalgesia that impair the quality of life of patients. OLP develops via a T cell-mediated immune process. Here, we examined the characteristics of the infiltrating T cells in terms of the T cell receptor (TCR) repertoires, T cell clonality, T cell phenotypes and cytokine production profiles. TCR repertoire analyses and CDR3 size spectratyping were performed using peripheral blood mononuclear cells (PBMCs) and tissue specimens of OLP biopsies from 12 patients. The cytokine expression profiles and T cell phenotypes were measured by real-time quantitative polymerase chain reaction. We observed that there were skewed TCR repertoires in the tissue samples (TCRVA8-1, VA22-1, VB2-1, VB3-1 and VB5-1) and PBMCs (TCRVA8-1, VB2-1, VB3-1 and VB5-1) from OLP patients. Furthermore, the CDR3 distributions in the skewed TCR subfamilies exhibited polyclonal patterns. We observed increases in CD4(+) T lymphocytes, interleukin (IL)-5, tumour necrosis factor (TNF)-alpha and human leucocyte antigen D-related in the OLP tissue specimens. Taken together, the present results suggest that T cells bearing these TCRs are involved in the pathogenesis of OLP, and that IL-5 and TNF-alpha may participate in its inflammatory process.

Bacterial superantigens and T cell receptor beta-chain-bearing T cells in the immunopathogenesis of ulcerative colitis.

Ulcerative colitis (UC) is a chronic relapsing-remitting inflammatory bowel disease (IBD) that affects the colon and the rectum producing debilitating symptoms, which impair ability to function and quality of life. The aetiology of IBD is incompletely understood, but within the lymphocyte population, specific T cell subsets are known to be major factors in the development of intestinal immune pathology while different subsets are essential regulators, controlling IBD. Hence, IBD is thought to reflect dysregulated T cell behaviour. This study was to investigate if the normal molecular configuration of the T cell receptor (TCR) repertoire is compromised in patients with UC. The percentage of T cell-bearing beta-chain 4 (TCRBV4) was high in patients with UC, and T cells showed polyclonal expansion in the presence of bacterial superantigens (SA) such as streptococcal mitogenic exotoxin Z-2 (SMEZ-2), indicating that bacterial SA promote specific TCRBV family expansion. Further, in patients with UC, the duration of UC was significantly longer in patients with skewed TCRBV4 compared with patients without TCRBV4 skewing, suggesting that long-term exposure to bacterial SA such as SMEZ-2 might promote systemic immune disorders like the remission-relapsing cycles seen in patients with UC. In conclusion, our observations in this study support the perception that the systemic activation of T cells by enteric bacterial SA might lead to a dysregulated, but exuberant immune activity causing the remission and flare-up cycle of mucosal inflammation in patients with UC. Future studies should strengthen our findings and increase understanding on the aetiology of IBD.

Adhesion dependent release of hepatocyte growth factor and interleukin-1 receptor antagonist from human blood granulocytes and monocytes: evidence for the involvement of plasma IgG, complement C3 and beta2 integrin.

OBJECTIVE: Evolving evidence of anti-inflammatory effects is observed in patients with rheumatoid arthritis or ulcerative colitis following periodic adsorptive granulocyte and monocyte (GM) apheresis with a column containing cellulose acetate (CA) beads as apheresis carriers. This study was undertaken to obtain insights into mechanisms of anti-inflammatory actions of adsorptive GM apheresis with CA beads. METHODS: In a series of in-vitro experiments, we investigated the effects of plasma proteins and the leucocytes beta2 integrin (CD18) on granulocyte adsorption to CA beads. RESULTS: Granulocyte adsorption to CA beads required plasma IgG, the complement C3 and was inhibited by an antibody to leucocytes CD18. Further, hepatocyte growth factor (HGF) and interleukin-1 receptor antagonist (IL-1ra) which have strong anti-inflammatory actions were released by granulocytes that adhered to CA beads. CONCLUSIONS: Plasma IgG, C3 derived complement activation fragments and leucocytes CD18 are involved in granulocyte adhesion to CA beads and hence the release of HGF and IL-1ra.

Cellulose acetate beads induce release of interleukin-1 receptor antagonist, but not tumour necrosis factor-alpha or interleukin-1beta in human peripheral blood.

OBJECTIVE: Dramatic improvements in clinical symptoms of rheumatoid arthritis and ulcerative colitis were observed after patients received granulocyte and monocyte adsorptive apheresis with a column containing cellulose acetate (CA) beads as adsorptive carriers. This study was to investigate the effect of CA beads on the generation of anti-inflammatory and pro-inflammatory cytokines in human blood. MATERIALS AND METHODS: We incubated human whole blood with CA beads at 37 degrees C for up to 2 h and measured tumour necrosis factor-alpha (TNF-alpha) interleukin-1beta (IL-1beta) and IL-1 receptor antagonist (IL-1ra) produced by leucocytes. IL-1ra was also measured at the inflow and outflow of a column containing CA beads as leucocyte adsorptive carriers for the treatment of patients with ulcerative colitis. RESULTS: CA beads induced significant release of IL-1ra from leucocytes, but not TNF-alpha or IL-1beta. In contrast, all three cytokines were released when leucocytes were stimulated with lipopolysaccharide. IL-1ra was also markedly elevated in the outflow of the leucocyte apheresis column. CONCLUSIONS: These results indicate that CA beads selectively induce IL-1ra release from leucocytes which should contribute to the anti-inflammatory effect of granulocyte and monocyte adsorptive apheresis with CA beads as apheresis carriers.