Several circumstances in cirrhosis could predispose a patient to IBO, such as alcohol abuse (Bode et al., 1984), malnutrition (Casafont et al., 1997), hypochlorhydria (Shindo et al., 1993), decreased IgA or bile salts in the intestine (Deitch et al., 1990) and disturbances of small bowel motility (Vantrappen et al., 1977; Runkel et al., 1993). This evidence concerns the gene CD79A and malnutrition.