Association of CTLA4 single nucleotide polymorphisms with viral but not autoimmune liver disease.

BACKGROUND: CTLA4 is an inhibitory receptor expressed on a subset of T lymphocytes. Single nucleotide polymorphisms of the CTLA4 gene have been implicated in autoimmune diseases, including autoimmune hepatitis and primary biliary cirrhosis. In reverse form, CTLA4 variations are associated with chronic infections such as chronic hepatitis B. METHODS: CTLA4 variations -318C>T and +49A>G were analyzed in 2366 patients with chronic liver disease of various etiologies, including 323 patients with chronic hepatitis B virus (HBV) infection, 1181 patients with chronic hepatitis C virus infection, 180 patients with primary biliary cirrhosis, and 127 patients with autoimmune hepatitis, as well as 202 healthy control individuals. Genotyping was performed by melting curve analysis. RESULTS: The -318C>T variation was underrepresented in patients with chronic HBV infection compared with healthy controls (14.6 vs. 25.7%, P=0.002) and with patients with chronic liver disease of other origin (14.6 vs. 20.7%, P=0.011). Patients with cryptogenic cirrhosis also showed a lower frequency of the -318T allele than healthy controls (12.0 vs. 25.7%, P=0.014). No association of the +49G>A variation was found with any diagnosis, including autoimmune hepatitis and primary biliary cirrhosis. CONCLUSION: We describe the association of the CTLA4 -318C>T variation with chronic HBV infection and cryptogenic cirrhosis but find no association of the +49G>A variation with autoimmune liver disease.

Angiopoietin-2 serum levels are elevated in patients with liver cirrhosis and hepatocellular carcinoma.

OBJECTIVES: Liver cirrhosis is characterized by remodeling leading to nodules that are difficult to discern from hepatocellular carcinoma (HCC). Alpha-fetoprotein (AFP) serum levels are used for the screening for HCC, with limited success. We evaluated angiopoietin-2 as a serum marker in patients with cirrhosis and with HCC. METHODS: In a retrospective study, we measured angiopoietin-2 serum levels in 131 patients with HCC, 180 patients with cirrhosis, and 40 healthy controls. We also determined AFP serum levels in patients with HCC and compared the test characteristics of both serum markers. The expression patterns of angiopoietin-2 were determined by in situ hybridization in healthy and cirrhotic livers as well as in HCC. RESULTS: Angiopoietin-2 serum levels were elevated in patients with liver cirrhosis (P < 0.0001) compared with healthy controls. Levels were further elevated in patients with HCC compared with healthy controls (P < 0.0001) and cirrhotic patients (P < 0.0001). The combination with AFP measurements led to improved discrimination between HCC and cirrhosis. Angiopoietin-2 message was present in tumor cells of HCCs but was absent from hepatocytes of cirrhotic and healthy livers. In cirrhosis, message was detected within the strands of fibrous tissue. CONCLUSIONS: Serum angiopoietin-2 levels are elevated in patients with cirrhosis, implicating a possible role of the angiopoietin-Tie-2 system for neoangiogenesis in cirrhosis. Serum levels are further elevated in patients with HCC, suggesting the potential use of angiopoietin-2 as a marker for the detection of cirrhosis and HCC.

Demonstration of PDC-E1 subunits as major antigens in the complement-fixing fraction M4 and re-evaluation of PDC-E1-specific antibodies in PBC patients.

BACKGROUND: Primary biliary cirrhosis (PBC) is characterized by the presence of antimitochondrial antibodies (AMA). Autoantibodies specific for the mitochondrial M4 antigen can be detected by a complement fixation test (CFT) but not by immunoblotting. The aim of this study was to elucidate the identity of the M4 antigen. PATIENTS AND METHODS: M4 proteins were purified by affinity chromatography using IgG fractions of PBC marker sera being CFT positive (n=5) or negative (n=5) and identified by Western blotting, silver staining and sequence analysis. Further, a cohort of 57 PBC patients was tested for the reactivity to M4 and pyruvate dehydrogenase complex (PDC). RESULTS: Two AMA patterns of the marker sera were visualized: CFT-positive sera were defined as PDC-E2(+)/E1(+) and the CFT-negative sera as PDC-E2(+)/E1(-). The major proteins in the M4 fraction could be related to the PDC-E1 subunits. A clear-cut association between anti-M4 reactivity in the CFT and the reactivity to both PDC subunits could also be documented in the cohort of 57 PBC patients showing anti-PDC-E1alpha and E1beta antibodies at a frequency of 74% and 67%. CONCLUSIONS: CFT reactivity against M4 antigens could be preferentially identified as a reaction against PDC-E1. As PDC-E1 subunits as compared with PDC-E2 lack lipoyl-binding sites, they probably have to be considered as an independent and important target.

Rescue therapy with tacrolimus in a patient with toxic megacolon.

BACKGROUND: Toxic megacolon is a life-threatening complication most commonly observed in patients with ulcerative colitis or Crohn's disease that is characterized by total or segmental nonobstructive colonic dilatation of at least 6 cm on plain abdominal films associated with systemic toxicity. CASE REPORT: We report an unusual case of fulminant steroid-refractory ulcerative colitis complicated by toxic megacolon treated successfully with the immunosuppressant tacrolimus. CONCLUSION: Tacrolimus administration induced clinical remission and bridged the time interval, until the standard immunosuppressant azathioprine could maintain clinical remission, thereby avoiding eminent emergency colectomy.

Selective internalization of monoclonal antibodies by B-cell chronic lymphocytic leukaemia cells.

B-cell chronic lymphocytic leukaemia (B-CLL) cannot be cured by conventional chemotherapy, therefore, toxin-linked therapeutic monoclonal antibodies (mAbs) are increasingly examined for their potential to improve clinical outcome. The current study aimed to identify mAbs that were internalized by the B-CLL cells of 14 patients, using both flow cytometry and confocal laser scanning microscopy. Anti-CD5, CD22 and CD40 mAbs were effectively taken up by B-CLL cells, whereas mAbs against CD19, CD20, CD23 and CD45 were not. This study may form a basis for further research to identify antibodies that may serve as carriers for toxins to treat B-CLL.