- Serum fibrosis markers. Serum samples will be taken at 3rd, 6th and 12th months post-transplant from peripheral circulation and frozen at -21ºC. Serum markers (HA, PIIINP, and TIMP-1) will be analyzed by a fully automated, two-site sandwich immunoassay using direct chemiluminometric technology (ADVIA Centayr XP, Siemens Healthcare Diagnositics). The algorithm including the three markers (3-M-ALG) {score= -7,412 + [ln (HA)x0,681] + [ln (PIIINP)x0.775] + [ln (TIMP-1)]x0,494} will be also obtained.