Complement activation and subsequent recruitment of inflammatory cells at the dermal/epidermal junction are thought to be essential for blister formation in bullous pemphigoid (BP), an autoimmune blistering disease induced by autoantibodies against type XVII collagen (COL17); however, this theory does not fully explain the pathological features of BP. Recently, the involvement of complement-independent pathways has been proposed. To directly address the question of the necessity of the complement activation in blister formation, we generated C3-deficient COL17-humanized mice. First, we show that passive transfer of autoantibodies from BP patients induced blister formation in neonatal C3-deficient COL17-humanized mice without complement activation. By using newly generated human and murine mAbs against the pathogenic noncollagenous 16A domain of COL17 with high (human IgG1, murine IgG2), low (murine IgG1), or no (human IgG4) complement activation abilities, we demonstrate that the deposition of Abs, and not complements, is relevant to the induction of blister formation in neonatal and adult mice. Notably, passive transfer of BP autoantibodies reduced the amount of COL17 in lesional mice skin, as observed in cultured normal human keratinocytes treated with the same Abs. Moreover, the COL17 depletion was associated with a ubiquitin/proteasome pathway. In conclusion, the COL17 depletion induced by BP autoantibodies, and not complement activation, is essential for the blister formation under our experimental system.

Inflammatory bowel disease (IBD) represents a group of chronic inflammatory diseases characterized by inflammation and relapsing gastrointestinal disorders. Recent studies have shown that Th17 cells, which are well known as key mediators of chronic inflammation, have a pivotal role in onset and development of IBD in humans and mice, alike. In recent years, it has been reported that IL-27, which is an IL-12-related heterodimeric cytokine consisting of EBI3 and p28 subunits, act directly on naive T cells to suppress the differentiation of Th17 cells. However, effects of exogenous IL-27 on the IBD are not well elucidated. To clarify the suppressive effect of IL-27 treatment on IBD, we applied the flexible linking method to EBI3 and p28 subunits and generated a single-chain human IL-27 (scIL-27). scIL-27 inhibited xenogenic mouse Th17 cell differentiation in vitro, indicating that scIL-27 also acts in mouse immune systems. In a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced mouse acute colitis model, subcutaneous scIL-27 treatment significantly improved the colon length, extent of necrosis, and ulceration and thickened epithelium and several pathological scores in a dose-dependent manner. scIL-27 clearly suppressed several inflammatory cytokines, including IL-17, in inflamed colon, except for anti-inflammatory cytokine IL-10. The mesenteric lymph node cells from scIL-27-treated mice also exhibited a reduced inflammatory response and, furthermore, a lower population of Th17 cells than those of PBS-treated mice. Finally, we showed the therapeutic efficacy of scIL-27 on TNBS-induced colitis even after active colitis was established. These results suggest new possible therapeutic approaches for IBD, including disorders such as Crohn's disease and ulcerative colitis.

IntroductionRecombinant human soluble thrombomodulin (rhsTM) is newly developed for the treatment of DIC. The purpose of this study was to evaluate the efficacy of the concomitant administration of rhsTM and antithrombin (AT).MethodsIn the first series, rats were treated with either 62.5, 125, 250 or 500 IU/kg (n = 6, each) of AT or 0.125, 0.25, 0.5 or 1.0 mg/kg (n = 6, each) of rhsTM followed by lipopolysaccharide (LPS) injection. 8 h later, the fibrinogen level was examined. In the second series, TM group was pretreated with 0.25 mg/kg of rhsTM, AT group was pretreated with 125 IU/kg of AT, AT/TM group was pretreated with both AT and rhsTM, and control group was pretreated with saline (n = 7, each). The platelet count, fibrinogen, ALT, LDH and high-mobility group box 1 (HMGB1) levels were measured. In addition, histologic changes in liver were examined. In the third series, survival was calculated up to 24 h.ResultsBoth AT and rhsTM produced a linear dose-response with regard to the fibrinogen level, with 125 IU/kg of AT and 0.25 mg/kg of rhsTM producing equivalent effects. The combined administration of AT and rhsTM significantly reduced the decrease in the platelet count and the fibrinogen level (P < 0.05, 0.01, respectively). The elevations in ALT and LDH were significantly suppressed in all treatment groups. The HMGB1 level and the histologic changes tended to indicate damage reduction. Survival was significantly better only in AT/TM group (P < 0.01).ConclusionsThe coadministration of AT and rhsTM might be effective for the treatment of severe sepsis.