What is behind the presence of anti-neutrophil cytoplasmatic antibodies in chronic liver disease?

ABSTRACT Background: Anti‐neutrophil cytoplasm antibodies (ANCA) have been detected in serum from patients affected by autoimmune CLD, and to a lesser extent, in serum of patients affected by non autoimmune CLD. The clinical significance of ANCA in these disorders is still unclear. Aims: To explore the clinical and diagnostic significance of ANCA in CLD. Materials and methods: Forty‐five sera from patients affected by HCV‐ and HBV‐related CLD (group 1), 29 sera from patients affected by alcohol‐related CLD (Group 2) and 33 sera from patients affected by autoimmune‐related liver diseases including chronic autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC), (Group 3) have been studied by using IIF and ELISA. Results: A low correspondence between the ANCA positivity obtained by IFI and ELISA was observed. The positivity for at least one ANCA antigen was observed in 60,0% of Group 1, in 44,8% of Group 2 and in 72,7% of Group 3. The relation between the aetiology of the disease and the number of positive ANCA tests in ELISA was not significant. The relation between the MELD score and the number of ANCA positivity in patients with cirrhosis in the autoimmune‐related CLD and in the viral‐related CLD has been investigated. In both Groups a significant worsening of MELD at increasing number of ANCA positivity was found. Moreover in patients without cirrhosis in Group 3 an increase in the ALT and AST activity in patients with at least one ANCA positivity was observed. Conclusions: These data suggest that the finding of ANCA by ELISA is common not only in autoimmune CLD but, also in viral‐related CLD. Patients with autoimmune‐related CLD express more frequently a multiple antigen reactivity as compared to those with viral‐related CLD. The positivity for ANCA might have a prognostic value in patients with viral‐related as well as autoimmune‐related cirrhosis since it is associated with worse MELD score.