Patients with autoimmune, vascular, biliary or tumoral liver disease were excluded from the study. Liver fibrosis was staged according to the Scheuer system as follows: No or mild fibrosis (no fibrosis or portal fibrosis without septa; F0 and F1), moderate fibrosis (portal fibrosis and few septa; F2), severe fibrosis (numerous septa with architectural

distortion, without cirrhosis; F3), and cirrhosis (F4) [20]. Liver biopsies that were learn more <15 mm long (except in the case of cirrhosis) were excluded from the histological analysis. The length of each liver biopsy specimen was established. A single experienced pathologist staged the liver biopsies. The serum levels of TIMP-1 and MMP-2 were determined in frozen sera stored at −80 °C, which had not previously been thawed. Commercial assays based on the quantitative sandwich enzyme immunoassay technique were used to measure serum

PF-562271 concentration levels of TIMP-1 (Quantikine®; Human TIMP-1 Immunoassay; R&D Systems, Minneapolis, MN, USA) and MMP-2 (Quantikine®; Human/Mouse/Rat MMP-2 (total) Immunoassay; R&D Systems). These assays were carried out following the manufacturer’s instructions. Briefly, a monoclonal antibody specific for TIMP-1 or MMP-2 was pre-coated onto a microplate. Standards and samples were pipetted into the wells and any TIMP-1 or MMP-2 present was bound by the immobilized antibody. After washing away any unbound substances, an enzyme-linked polyclonal antibody specific for TIMP-1 or MMP-2 was added to the (-)-p-Bromotetramisole Oxalate wells. Following a

wash to remove any unbound antibody-enzyme reagent, a substrate solution was added to the wells and colour developed in proportion to the amount of TIMP-1 or MMP-2 bound in the initial step. The colour development was stopped and the intensity of the colour was measured. The AST to platelet ratio index (APRI) was calculated by dividing the AST concentration (IU/L), expressed as the number of times above the upper limit of normal (ULN), by the platelet count (109 cells/L): AST (/ULN) × 100/platelet count. This index has been validated in HIV/HCV-coinfected patients [3,4]. If APRI is ≥1.5, patients can be classified as having significant fibrosis [fibrosis stage (F) ≥2], with a positive predictive value (PPV) of 87% [3]. The low cut-off of APRI <0.5 was inaccurate to exclude F≥2 [3]. The main outcome variables were the detection of F≥2 and of F4 with a combination of variables at the date of liver biopsy.