A preliminary investigation of 5 patients with CDI shows that transfer of sterile filtrates from donor stool (FFT), rather than fecal microbiota, can be sufficient to restore normal stool habits and eliminate symptoms. This finding indicates that bacterial components, metabolites, or bacteriophages mediate many of the effects of FMT, and that FFT might be an alternative approach, particularly for immunocompromised patients.

Sarcoidosis is a polygenic immune disorder with predominant manifestation in the lung. Genome-wide linkage analysis previously indicated that the extended major histocompatibility locus on chromosome 6p was linked to susceptibility to sarcoidosis. Here, we carried out a systematic three-stage SNP scan of 16.4 Mb on chromosome 6p21 in as many as 947 independent cases of familial and sporadic sarcoidosis and found that a 15-kb segment of the gene butyrophilin-like 2 (BTNL2) was associated with the disease. The primary disease-associated variant (rs2076530; P(TDT) = 3 x 10(-6), P(case-control) = 1.1 x 10(-8); replication P(TDT) = 0.0018, P(case-control) = 1.8 x 10(-6)) represents a risk factor that is independent of variation in HLA-DRB1. BTNL2 is a member of the immunoglobulin superfamily and has been implicated as a costimulatory molecule involved in T-cell activation on the basis of its homology to B7-1. The G --> A transition constituting rs2076530 leads to the use of a cryptic splice site located 4 bp upstream of the affected wild-type donor site. Transcripts of the risk-associated allele have a premature stop in the spliced mRNA. The resulting protein lacks the C-terminal IgC domain and transmembrane helix, thereby disrupting the membrane localization of the protein, as shown in experiments using green fluorescent protein and V5 fusion proteins.

Crohn disease and ulcerative colitis are two subphenotypes of inflammatory bowel disease (IBD), a complex disorder resulting from gene-environment interaction. We refined our previously defined linkage region for IBD on chromosome 10q23 and used positional cloning to identify genetic variants in DLG5 associated with IBD. DLG5 encodes a scaffolding protein involved in the maintenance of epithelial integrity. We identified two distinct haplotypes with a replicable distortion in transmission (P = 0.000023 and P = 0.004 for association with IBD, P = 0.00012 and P = 0.04 for association with Crohn disease). One of the riskassociated DLG5 haplotypes is distinguished from the common haplotype by a nonsynonymous single-nucleotide polymorphism 113G→A, resulting in the amino acid substitution R30Q in the DUF622 domain of DLG5. This mutation probably impedes scaffolding of DLG5. We stratified the study sample according to the presence of risk-associated CARD15 variants to study potential gene-gene interaction. We found a significant difference in association of the 113A DLG5 variant with Crohn disease in affected individuals carrying the risk-associated CARD15 alleles versus those carrying non-risk-associated CARD15 alleles. This is suggestive of a complex pattern of genegene interaction between DLG5 and CARD15, reflecting the complex nature of polygenic diseases. Further functional studies will evaluate the biological significance of DLG5 variants. D10S201 D10S213 cM

Inflammatory bowel diseases (IBD)—Crohn’s disease and ulcerative colitis—are relapsing chronic inflammatory disorders which involve genetic, immunological, and environmental factors. The regulation of TNF-α, a key mediator in the inflammatory process in IBD, is interconnected with mitogen-activated protein kinase pathways. The aim of this study was to characterize the activity and expression of the four p38 subtypes (p38α–δ), c-Jun N-terminal kinases (JNKs), and the extracellular signal-regulated kinases (ERK)1/2 in the inflamed intestinal mucosa. Western blot analysis revealed that p38α, JNKs, and ERK1/2 were significantly activated in IBD, with p38α showing the most pronounced increase in kinase activity. Protein expression of p38 and JNK was only moderately altered in IBD patients compared with normal controls, whereas ERK1/2 protein was significantly down-regulated. Immunohistochemical analysis of inflamed mucosal biopsies localized the main expression of p38α to lamina propria macrophages and neutrophils. ELISA screening of the supernatants of Crohn’s disease mucosal biopsy cultures showed that incubation with the p38 inhibitor SB 203580 significantly reduced secretion of TNF-α. In vivo inhibition of TNF-α by a single infusion of anti-TNF-α Ab (infliximab) resulted in a highly significant transient increase of p38α activity during the first 48 h after infusion. A significant infliximab-dependent p38α activation was also observed in THP-1 myelomonocytic cells. In human monocytes, infliximab enhanced TNF-α gene expression, which could be inhibited by SB 203580. In conclusion, p38α signaling is involved in the pathophysiology of IBD.

IntroductionIL6 has major functions in inflammatory reactions of the body. 1,2 Mice with a targeted inactivation of the IL6 gene are completely protected in animal models of rheumatoid arthritis 3,4 and multiple sclerosis. 5 Furthermore, regenerative reactions such as wound healing and liver regeneration are severely compromised in IL6 Ϫ/Ϫ mice. 6 A soluble form of the IL6R can bind IL6 with the same affinity as the membrane-bound form and the complex of IL6 and the soluble IL6R (sIL6R) can induce signaling in a process called IL6 transsignaling. 7,8 Because the IL6R is only sparely expressed, IL6 transsignaling dramatically increases the number of potential IL6 target cells. 9 This is relevant for inflammatory processes in vivo, because endothelial cells and smooth muscle cells, which play key roles in inflammation, lack IL6R expression. The interest in the role of IL6 in inflammatory processes has recently been intensified by the finding that the differentiation of TH 17 cells, which is a prerequisite for inflammatory damage during autoimmune disease, shows a dependence on IL6 in combination with TGF␤. 10 Recent studies with animal models of inflammatory bowel disease, 11,12 peritonitis, 13 rheumatoid arthritis, 14,15 and inflammatory colon cancer 16 suggest that IL6 transsignaling serves as the major proinflammatory paradigm of IL6 signaling under pathophysiologic conditions.To further analyze the relevance of IL6-transsignaling in vivo we generated a mouse model in which IL6-transsignaling is specifically abrogated. There have been reports describing the generation of knock-in mice with noncleavable L-selectin and noncleavable TNF-␣, showing that shedding of membrane proteins was important for antigen-stimulated lymphocyte migration and for secondary lymphoid organ architecture. 17,18 Such a strategy is impractical in the case of the sIL6R because its generation is complex and can be generated by ectodomain shedding as well as by translation from an alternatively spliced mRNA. Furthermore, shedding of the IL6R was also shown to occur at multiple cleavage sites and performed by multiple and distinct sheddase activities. [19][20][21][22] We therefore decided to generate transgenic mice overexpressing the sgp130Fc-protein that had been demonstrated to completely block IL6 transsignaling without affecting activities via the membrane bound IL6R. Blocking of IL6 transsignaling via sgp130Fc is independent of the mode of sIL6R generation. The need for a large molar excess of the sgp130Fc-protein necessitated the development of a codon optimization strategy that should be relevant for the construction of all animal models, which are based on the overexpression of heterologous proteins.The data presented here clearly show that sgp130Fc transgenic mice display an IL6-transsignaling knockout-like phenotype and establish them as the only possible in vivo model of this IL6-transsignaling paradigm. Here, we demonstrate in the air-pouch model of inflammatory activation that the transition from the neutrophil-dominated phase...