11. It should be performed HBV and HCV serologies prior to inclusion. If HbsAg is positive it is recommended to reject the existence of replicative phase (HbaAg+, DNA HBV+). If these were positives the inclusion is not recommended, remaining at investigators' discretion the preventive treatment with lamivudine. If a potential patient is positive for anti-HCV antibodies, presence of the virus should be ruled out with a qualitative PCR, or the patient should NOT be included in the study (if a qualitative PCR cannot be performed then patient will not be able to enter the study).