HLA-DQ genotyping combined with serological markers for the diagnosis of celiac disease: is intestinal biopsy still mandatory?

OBJECTIVES: The aim of this study was to evaluate the value of HLA-DQ2/DQ8 allelic genotyping combined with serologic testing for the diagnosis of celiac disease (CD). PATIENTS AND METHODS: One hundred seventy children, who underwent jejunal biopsy for digestive symptoms or malnutrition, were tested for HLA-DQ2/DQ8 and serologic markers (tTG and/or anti-endomysial antibodies). Children were classified in 2 groups, according to jejunal histology: group 1, when partial or total villous atrophy was associated with an increased intraepithelial lymphocytosis suggesting CD, and group 2, when these histological criteria were absent. RESULTS: Eight children were excluded from the study because their intestinal histology was not informative; 82 children were classified in group 1 and 80 in group 2. Eighty-one of 82 children in group 1 were positive for HLA and serologic testing. The other child had negative HLA and serologic testing but marked villous atrophy, and further investigation showed an allergic disease. Among the 80 children in group 2, 53 were negative for both HLA and serologic testing, 22 were positive for HLA but negative for serologic testing, 2 were negative for HLA and positive for serologic testing, and 3 patients were positive for both HLA and serologic testing. The last 3 children were shown to have an autoimmune background and had probably a latent form of CD. The association of HLA-DQ2/DQ8 and serologic markers had a sensitivity of 98.8%, a specificity of 96.2%, a positive likelihood ratio of 26.3, and a negative likelihood ratio of 0.013. CONCLUSIONS: The association of positive HLA-DQ2/DQ8 and serologic testing has a high predictive value for CD. We suggest that symptomatic children with high titers of immunoglobulin (Ig)A tTG could be diagnosed as patients with CD without performing jejunal biopsy. In other children, HLA-DQ2/DQ8 could be useful to exclude the diagnosis of CD if negative. In cases of low IgA tTG titers or in patients with IgA deficiency, intestinal biopsy remains mandatory.

Specific activation of the different fibrogenic cells in rat cultured liver slices mimicking in vivo situations.

Due to the loss of cell-cell and cell-matrix interactions, cell culture models poorly mimic the in vivo situation. Therefore, we tested the applicability of precision-cut liver slices (PCLS) to study the early activation of the two main liver fibrogenic cell subpopulations: hepatic stellate cells (HSC) and portal fibroblasts (PF). PCLS were treated with thioacetamide or acetaminophen to induce HSC activation. In PCLS culture, both were able to trigger centrolobular lesion and HSC activation as observed in vivo. However, thioacetamide also presented a toxic effect on portal tract cells. In this PCLS model of centrolobular lesion, the antioxidant N-acetylcysteine was able to prevent acetaminophen-induced injury. To induce a specific activation of PF, PCLS were treated with epidermal growth factor or beta-oestradiol. As in vivo, epidermal growth factor and beta-oestradiol induced bile duct epithelial cell proliferation accompanied by PF activation; however, beta-oestradiol also triggers sinusoidal cell proliferation. We demonstrated that treatments usually used in vivo to induce liver fibrosis allow, in cultured PCLS, the specific activation of the two main liver fibrogenic cell subpopulations, making this model very useful to study the mechanisms involved in early fibrogenic cell activation.

Dietary lecithin protects against cholestatic liver disease in cholic acid-fed Abcb4- deficient mice.

Mutations in multidrug resistance 3 gene (MDR3 or ABCB4) underlie progressive familial intrahepatic cholestasis type 3 (PFIC3), a severe pediatric liver disease progressing to cirrhosis. Abcb4-/- mice exhibit slowly developing hepatic lesions that can be accelerated by feeding a cholic acid (CA)-supplemented diet. We investigated the beneficial effects of a soybean lecithin (L)-supplemented diet in this model of liver disease. Abcb4-/- mice and wild-type (WT) controls were divided in four groups by the diet they were fed: control (C) diet, L-supplemented diet, CA-supplemented diet, and L- and CA-supplemented (L+CA) diet. After 2 wk on these regimens, liver enzymes and bilirubin were measured in serum with bile flow, total bile acids, and cholesterol (CHOL) and phospholipid (PL) concentrations in bile. Ductular hyperplasia, portal fibroblastic cell proliferation, myofibroblast activation, and hepatic fibrosis were quantified on liver sections. Abcb4-/- mice fed the C diet exhibited mild liver damage. CA produced very high elevations of serum liver enzymes and bilirubin with significant bile duct proliferation, peribiliary fibroblast activation, and fibrosis. The L-supplemented diet dramatically mitigated the hepatic damage in CA-supplemented diet animals. We conclude that L is protective against liver disease in Abcb4-/- mice and suggest that it could offer potential benefit in PFIC3.

Effects of bile acids on biliary epithelial cell proliferation and portal fibroblast activation using rat liver slices.

During cholestasis, bile acids accumulate in the liver, and induce cellular alterations. Cholestasis is a major cause of liver fibrosis. We have used precision-cut liver slices (PCLS) in culture to investigate the effects of bile acids on hepatic cells. Rat PCLS were placed on an insert in a vial containing culture medium, and gently agitated on a roller platform. PCLS were treated with 100 microM taurolithocholate (TLC), taurodeoxycholate (TDC) or taurocholate (TC) for 24 or 48 h. PCLS viability was measured, and immunohistochemistry was performed with antibodies against active caspase 3, platelet-derived growth factor (PDGF) receptor-beta and ED-A fibronectin. TDC and TLC, two hydrophobic bile acids, induced hepatocyte necrosis and apoptosis, whereas TC, an hydrophilic bile acid, improved slice viability as compared with controls. Both TDC and TC induced biliary epithelial cell proliferation, together with portal fibroblast proliferation and activation, as shown by PDGF receptor-beta and ED-A fibronectin expression. TLC induced biliary epithelial cell apoptosis. Our results indicate that individual bile acids induce cell type-specific effects in a complex liver microenvironment. The fact that PCLS support biliary epithelial cell and portal fibroblast proliferation will make this model very useful for the study of the mechanisms involved in portal fibrosis.