Dysregulation of granulocyte, erythrocyte, and NK cell lineages in Fli-1 gene-targeted mice

Targeted disruption of the Friend leukemia integration 1 (Fli-1) proto-oncogene results in severe dysmegakaryopoiesis and embryonic lethality. We used morula-stage aggregation as a strategy to further clarify the hematopoietic defects of the Fli-1 gene-targeted mice. Analyses of lineage expression of Fli-1(+/-) and Fli-1(-/-) cells in the peripheral blood and bone marrow of chimeric mice consistently demonstrated reduced numbers of neutrophilic granulocytes and monocytes and increased numbers of natural killer (NK) cells. Transplantation studies using sorted Fli-1 mutant cells produced similar findings. Clonal culture studies of bone marrow cells revealed increased numbers of granulocytic and early erythroid progenitors in the Fli-1(+/-) cells. The sorted Fli-1(-/-) bone marrow cells revealed specific down-regulation of CCAAT/enhancer binding protein-alpha (C/EBPalpha) and C/EBPepsilon, and the receptors for granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF), consistent with their critical roles in granulopoiesis. Collectively, these observations suggest previously unknown physiologic roles for Fli-1 in granulocytic, erythroid, and NK cell proliferation and differentiation. Production of chimeras by morula-stage embryo aggregation is an effective way to unravel cell-autonomous hematopoietic defects in gene-targeted mice.     

Anticoagulation therapy dramatically improved severe sigmoiditis with findings resembling inflammatory bowel disease, which was caused by mesenteric venous thrombosis

Mesenteric venous thrombosis is an insidious disease, with a high mortality rate typically attributed to the long delay in diagnosis. Rapid diagnosis and treatment are important. Here, we present a patient with idiopathic inferior mesenteric venous (IMV) thrombosis. A 65-year-old man presented with constant abdominal pain associated with fever and bloody diarrhea. He was diagnosed with severe ulcerative colitis and was treated with mesalazine and prednisolone. The prednisolone was tapered because of liver dysfunction, and he received total parenteral nutrition for a month. His abdominal pain and bloody diarrhea worsened, and he lost 5?kg of weight. He was then transferred to our institute. Computed tomography showed thickening of the left colon. Colonoscopy showed diffuse colitis with multiple ulcers, large edematous folds, congested mucosa, and stenosis of the sigmoid colon, with sparing of the rectum, raising the possibility of IMV thrombosis. Angiography confirmed IMV thrombosis. Anticoagulation therapy was initiated with intravenous heparin followed by oral warfarin. His abdominal pain and diarrhea resolved, and he was discharged from hospital. Six months later, he remained asymptomatic with normal colonoscopic findings.     

Intrahepatic biliary epithelial cell damage and inflammation in portal tract in association with chronic colitis-harboring TCRalpha(-/-) mice.

BACKGROUND: Intrahepatic bile ducts are the target for inflammation in both primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The mechanisms of biliary epithelial cell damage in both diseases are not clearly understood. Ulcerative colitis (UC) is one of the known complications in PSC. In this study, we assessed the possible influence of apoptosis inhibitor expressed by macrophages (AIM) on intrahepatic bile ducts in the chronic colitis-harboring condition by generating T cell receptor alpha-deficient (TCRalpha(-/-))xAIM-deficient (AIM(-/-)) double-knockout mice. METHODS: TCRalpha(-/-)xAIM(-/-) mice were generated by crossbreeding TCRalpha(-/-) mice with AIM(-/-) mice. At 24 weeks of age, mice were sacrificed to obtain liver tissues for pathological examinations, and blood was collected to study the serum levels of IgG, IgM and IgA. RESULTS: In female TCRalpha(-/-)xAIM(-/-) mouse livers, mixed cellular infiltration in the portal area and epithelial cell damage in bile ducts were observed, when compared with female TCRalpha(-/-)xAIM(+/-) and male TCRalpha(-/-)xAIM(-/-) mice. Inflammation in hepatic parenchyma was mild to none in all mice. In the female mouse group, the serum IgA level was relatively increased in TCRalpha(-/-)xAIM(-/-) mice compared to TCRalpha(-/-)xAIM(+/-) mice. CONCLUSION: The defect of AIM might be involved not only in colonic mucosal inflammation but also in portal inflammation, as well as in biliary epithelial cell damage in the livers of female TCRalpha(-/-)xAIM(-/-) mice.     

Association of IRF5 polymorphisms with systemic lupus erythematosus in a Japanese population: support for a crucial role of intron 1 polymorphisms

OBJECTIVE: To determine whether the IRF5 gene, which encodes interferon regulatory factor 5, is associated with systemic lupus erythematosus (SLE) in a Japanese population. METHODS: A case-control study was performed in 277 SLE patients and 201 healthy controls. Associations between the IRF5 genotype and levels of messenger RNA (mRNA) for interferon (IFN) pathway genes were examined using an mRNA expression database of HapMap samples. RESULTS: Carriers of the rs2004640T single-nucleotide polymorphism (SNP) were slightly increased among SLE patients (58.8%) as compared with controls (50.2%). When data from our Japanese population were combined with previously published data from a Korean population, the T allele frequency was found to be significantly increased in SLE patients (P = 8.3 x 10(-5)). While no association was observed for the rs10954213 SNP or the exon 6 insertion/deletion, significant associations with 3 intron 1 SNPs (-4001, rs6953165, and rs41298401) were found. The allele frequency of rs41298401G was significantly decreased in SLE patients (13.0% versus 18.7% in controls; P = 0.017), and the allele frequency of rs6953165G, which was in absolute linkage disequilibrium with -4001A, was increased in SLE patients (8.8% versus 5.2% in controls; P = 0.034). The Caucasian risk haplotype was not present; instead, a protective haplotype carrying rs2004640G, rs41298401G, the deletion in exon 6, and rs10954213A was identified. SNP rs10954213, but not intron 1 SNPs, was associated with IRF5 at the mRNA level; nevertheless, intron 1 SNPs were also associated with levels of mRNA for several IFN pathway genes, suggesting a functional role. CONCLUSION: IRF5 was found to be associated with SLE in Asian populations. Intron 1 SNPs, rather than exon 6 and 3'-untranslated region polymorphisms, appeared to play a crucial role.     

Characterization of structures with T-lymphocyte aggregates in ileal villi of Crohn's disease

OBJECTIVES: Epithelioid granulomas with transmural inflammation are a characteristic histological feature in Crohn's disease (CD). However, these are not frequently detected by histopathological examination in the biopsy specimens. Here, we demonstrated unique structures with T-lymphocyte aggregates (TLAs) that were specifically found in ileal villi of CD. We characterized the histological and phenotypical features of these structures and assessed the diagnostic value of TLAs for CD. METHODS: Tissue samples were obtained from the inflamed and uninflamed areas of ileal and colonic mucosa of 32 patients with CD. For controls, mucosal samples were obtained from unaffected areas of 18 patients with colon cancer and inflamed and uninflamed areas of 12 patients with ulcerative colitis (UC). RESULTS: 1) In 21 of 32 cases of CD (66%), we found unique structures with lymphoid cell aggregates that were localized in villi of ileum. These structures were not detected in any normal or UC intestine. 2) These structures were composed mainly of T cells, and CD4+ CD45RO+ cells dominated. Neither B cells nor c-kit positive immature lymphocytes were found. Moreover, CD68 positive macrophages were demonstrated in these aggregates, and cells positive for interleukin 18, a pivotal cytokine for Th1 differentiation, were expressed. 3) The aggregates were detected in seven of 13 patients with CD in whom granuloma was not detected by precise histopathological examination. Furthermore, we detected TLAs even in the ilea of two of four CD patients (50%) whose affected lesions were limited to the colon. CONCLUSIONS: We demonstrated TLAs in intestinal villi that may contribute to the pathogenesis of CD. Detection of these lymphocyte aggregates is helpful for diagnosis of CD when granuloma is not found.