Performance of enhanced liver fibrosis plasma markers in asymptomatic individuals with ZZ α1-antitrypsin deficiency.

Objectives: Alpha1-antitrypsin deficiency (AATD) is a common genetic cause of chronic liver disease. According to retrospective studies, up to 25% of those with homozygous ZZ (Glu 342 to Lys) AATD suffer from liver cirrhosis and/or liver cancer in late adulthood. We hypothesized that the plasma markers for liver fibrosis, necrosis, and apoptosis may identify AATD individuals at higher risk for liver diseases.

Methods: The study cohort included 52 clinically healthy ZZ AATD individuals of 34 years of age, identified in the Swedish neonatal screening of 1972-1974, and 81 age-matched controls with normal MM AAT variant. We analyzed plasma levels of the enhanced liver fibrosis (ELF) panel, including plasma tissue inhibitor of metalloprotease-1, amino-terminal propeptide of type III collagen and hyaluronic acid (HA), and the M30 and M65 antigens, markers for apoptosis/necrosis.

Results: Higher levels of tissue inhibitor of metalloprotease-1 (52%, P<0.001), amino-terminal propeptide of type III collagen (12%, P<0.05), HA (17% not significant), and M65 (13.4%, P=0.043) were found in ZZ than in MM patients. In the ZZ group, plasma levels of AAT correlated with M65 (P<0.01) and with HA (P<0.05). On the basis of the ELF panel, M30 and M65, a logistic regression model enabled us to correctly classify 81.2% of the originally grouped ZZ and MM cases with a sensitivity of 73.1% and a specificity of 86.4%.

Conclusion: The ELF markers are associated with ZZ AATD at early adulthood, and can be considered as a useful tool to identify ZZ cases at an increased risk of developing liver diseases later in life.