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IgG4-related disease has gained increased attention worldwide. While the initial focus was on autoimmune pancreatitis which was first described in Asian populations and turned out to be of relevance in Western populations too, the scope has recently broadened towards a notion of a multi-systemic disease with very diverse manifestations such as autoimmune pancreatitis, IgG4-related sclerosing cholangitis (IgG4-SC), retroperitoneal fibrosis and tubulointerstitial nephritis. IgG4-SC (also known as IgG4-associated cholangitis, IAC) represents a rare but clinically challenging differential diagnosis in patients with obstructive jaundice and proximal extra- or intrahepatic biliary strictures which can be mistaken for cholangiocarcinoma (CC). We present the case of a 79-year-old male patient who presented with obstructive jaundice and biliary strictures at the hepatic duct bifurcation without any evidence for autoimmune pancreatitis and without elevation of serum IgG4-concentrations who underwent hemihepatectomy for suspected CC. However, on histological examination of the resection specimen CC could not be confirmed. It was only after several episodes of obstructive jaundice had reoccurred that the diagnosis of IgG4-SC could be established by reexamination of the surgical specimen which showed extensive infiltration with IgG4-positive plasma cells. Appropriate medical treatment with steroids and azathioprine led to complete remission of the disease. Early recognition of IgG4-SC can save patients from potential harmful and unnecessary surgical interventions. Here we describe the clinical features of this rare case of IgG4-SC with extensive liver tissue infiltration with IgG4-positive cells but without elevated serum IgG4 concentration or evidence of autoimmune pancreatitis. We describe diagnostic criteria for IgG4-SC and review recent insights in pathophysiology and treatment options.

The most recently introduced BLI technology is accurate enough to leave distal colorectal polyps in place without resection. BLI also allowed for assignment of postpolypectomy surveillance intervals. This approach therefore has the potential to reduce costs and risks associated with the redundant removal of diminutive colorectal polyps.

Abscess formation associated with secondary peritonitis causes severe morbidity and can be fatal. Formation of abscesses requires the presence of CD4+ T-cells. Zwitterionic polysaccharides (ZPSs) represent a novel class of immunomodulatory bacterial antigens that stimulate CD4+ T-cells in a major histocompatibility complex (MHC) class II-dependent manner. The capsular polysaccharide Sp1 of Streptococcus pneumoniae serotype 1 possesses a zwitterionic charge with free amino groups and promotes T-cell-dependent abscess formation in an experimental mouse model. So far, nothing is known about the function of Interleukin (IL)-6 in intraperitoneal abscess formation. Here, we demonstrate that macrophages and dendritic cells (DCs), the most prevalent professional antigen-presenting cells involved in the formation of abscesses, secrete Interleukin (IL)-6 and are incorporated in the abscess capsule. Sp1 inhibits apoptosis of CD4+ T-cells and causes IL-17 expression by CD4+ T-cells in an IL-6-dependent manner. Abrogation of the Sp1-induced pleiotropic effects of IL-6 in IL-6-deficient mice and mice treated with an IL-6-specific neutralizing antibody results in significant inhibition of abscess formation. The data delineate the essential role of IL-6 in the linkage of innate and adaptive immunity in polysaccharide-mediated abscess formation.

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