Causes of liver disease in an adult population with heterozygous and homozygous alpha 1-antitrypsin deficiency

Liver disease in adults with severe alpha-1-antitrypsin deficiency

BACKGROUND

The proportion of adults with liver disease due to severe alpha-1-antitrypsin deficiency (AATD), with PiZZ phenotype, is not clear. The markers of the AATD liver disease, how it progresses, and measures for its prevention have not been established. The aim of this study was to analyze the risk of liver disease in individuals with severe AAT deficiency (PiZZ).

METHODS

Longitudinal clinical and laboratory data were obtained from the Swedish National registers, by cross-linkage between the Swedish national AATD register, the Swedish National Patient Register, the National Cancer Register and the National Causes of Death Register.

RESULTS

A total of 1595 PiZZ individuals were included in the analyses. The mean follow-up time was 12 years (range 0.3-24). The mean number of follow-ups was 5 (range 2-15). Two or more liver function tests (LFTs) were available in 1123 individuals, and 26% of them (n = 290) had repeated elevated LFTs during the follow-up. The prevalence of any liver disease was 10% (n = 155). Liver cirrhosis was found in 7% of the individuals (n = 116) and hepatocellular carcinoma in 2% (n = 29). The mean age at the onset of liver disease was 61 (SD 15) years. In multivariate analyses, the male gender, age over 50 years, repeated elevated LFTs, hepatitis virus infection, and a diagnosis of diabetes were associated with increased risk of developing liver disease in adulthood (p < 0.01).

CONCLUSION

The prevalence of liver disease in adult PiZZ individuals is 10%. Age over 50 years, the male gender, repeated elevated liver enzymes, hepatitis, and the presence of diabetes mellitus are risk factors for developing liver disease.

Alpha-1-antitrypsin phenotypes in adult liver disease patients

Alpha-1-antitrypsin (AAT) is an important serine protease inhibitor in humans. Hereditary alpha-1-antitrypsin deficiency (AATD) affects lungs and liver. Liver disease caused by AATD in paediatric patients has been previously well documented. However, the association of liver disease with alpha-1-antitrypsin gene polymorphisms in adults is less clear. Therefore, we aimed to study AAT polymorphisms in adults with liver disease. We performed a case-control study. AAT polymorphisms were investigated by isoelectric focusing in 61 patients with liver cirrhosis and 9 patients with hepatocellular carcinoma. The control group consisted of 218 healthy blood donors. A significant deviation of observed and expected frequency of AAT phenotypes from Hardy-Weinberg equilibrium (chi-square = 34.77, df 11, P = 0.000) in the patient group was caused by a higher than expected frequency of Pi ZZ homozygotes (f = 0.0143 and f = 0.0005, respectively, P = 0.000). In addition, Pi M homozygotes were more frequent in patients than in controls (63% and 46%, respectively, P = 0.025). Our study results show that Pi ZZ homozygosity in adults could be associated with severe liver disease. Presence of Pi M homozygosity could be associated with liver disease via some mechanism different from Z allele-induced liver damage through accumulation of AAT polymers.

Tempting liver fibrosis? Long-term psoriatic methotrexate therapy and heterozygous alpha1-antitrypsin deficiency

BACKGROUND

Dermatologists, or pathologists, occasionally need to decide whether or not to continue methotrexate therapy in a patient with an identifiable risk factor for liver fibrosis, in this instance heterozygous alpha(1)-antitrypsin deficiency.

CASE PRESENTATION

We relate our experience with an elderly male patient, diagnosed as having alpha(1)-antitrypsin deficiency on a liver biopsy, genotypically confirmed as PiMZ. He had been receiving methotrexate for psoriasis for 17 years with a cumulative dose of 7,200 mg. He was monitored by biochemical profiling and interval (10) liver biopsies. Non-specific changes were seen on liver histology although grade 1 liver fibrosis was seen in his last 2 biopsies.

CONCLUSION

We suggest that methotrexate therapy is relatively safe in patients with heterozygous alpha(1)-antitrypsin deficiency, with no other risk factor. We however advise that the risk of fibrosis should be monitored and that the patient receives appropriate counselling.

Pathologic features of chronic hepatitis. A review and update

The general histopathologic changes of chronic hepatitis and those related to the various causes are reviewed. Consideration also is given to underlying or associated diseases and to mixed infections in chronic viral hepatitis. Changes occurring in exacerbations or relapses are described. Selected histopathologic changes are illustrated. The nomenclature is reviewed briefly, with emphasis on separation of activity from stage of disease.

Enhanced phenotypic expression of alpha-1-antitrypsin deficiency in an MZ heterozygote with chronic hepatitis C

A middle-aged white man of Scotch-Irish ancestry, being treated for chronic hepatitis C, was found to be heterozygous for alpha1-antitrypsin deficiency (PiMZ phenotype) after diagnostic PAS-positive, diastase-resistant globules were detected in a liver biopsy. The globules had not been present in a biopsy obtained 4 yr previously. He was also found to be heterozygous for the cys282tyr mutation of the HFE gene, which is the chief cause of HLA-linked hereditary hemochromatosis (HHC). His liver disease progressed over 4 yr from mild hepatitis to moderate hepatitis with cirrhosis despite therapy with interferon-alpha, and phlebotomy plus interferon. These conditions appeared to have synergistic effects, with the chronic viral hepatitis unmasking the alpha1AT deficiency, and the alpha1AT deficiency (and possibly the heterozygosity for HHC), exacerbating the course of the hepatitis C.

Pathogenesis and pathology of liver disease associated with alpha 1-antitrypsin deficiency

alpha 1-Antitrypsin (alpha 1-AT) accumulates in the rough endoplasmic reticulum through a mechanism of polymerization. Polymerization is favored by the incorrect tertiary structure of the alpha 1-AT caused by a point mutation at position 342 of the protein. Accumulation of alpha 1-AT in the liver cells (and in hepatocytes and colangiocytes) is not sufficient per se to explain the liver disease that is manifested in a minority of PiZ subjects and thus, a trigger factor must be hypothesized. A virus (hepatitis C virus or some other kind of virus not identified as yet) is among the most probable trigger factors. In Z subjects (among the general population), relevant liver disease is probably a more rare event than thought in the past and most of these subjects escape major liver disease. Usually, liver disease is not a significant problem in patients with COPD.