Glutathione-S-Transferase M1 null genotype in autoimmune hepatitis

The role of polymorphisms of glutathione S-transferases GSTM1, M3, P1, T1 and A1 in susceptibility to alcoholic liver disease

AIMS AND METHODS

Oxidant stress is proposed to be an important pathogenic factor in liver damage related to alcohol. The glutathione S-transferases (GSTs) are a group of polymorphic enzymes that are important in protection against oxidant stress. As there is evidence for genetic susceptibility to alcohol-related liver disease we have compared the frequency of polymorphisms of GSTM1, M3, P1, T1 and A1 by polymerase chain reaction (PCR) on leucocyte DNA in patients from North Staffordshire, Birmingham and Liverpool with alcohol-related chronic liver disease heavy drinking and normal local controls.

RESULTS

There were no significant differences in GSTM1, GSTM3 or GSTP1 genotype frequencies among patients, drinking and non-drinking controls from the three centres. There was a significant increase in the GSTT1 null Liverpool alcoholic liver disease (ALD) patients compared with corresponding non-drinking controls (26.3 and 14.6%, respectively; P = 0.044, odds ratio (OR) = 2.1, 95% CI = 1.1-4.7) though this was not repeated in the Birmingham and North Staffordshire cohorts. For GSTA1, the -69 CC genotype was associated with increased risk of ALD in the Liverpool group, but a reduced risk in the North Staffordshire group.

CONCLUSIONS

We have failed to demonstrate within the limitation of a case-control study a reproducible significant association of GST polymorphisms with susceptibility to ALD but there are suggestions that GSTA1 and GSTT1 warrant further study.

Frequency and significance of anti-glutathione S-transferase autoantibody (anti-GST A1-1) in autoimmune hepatitis

Several phase I and phase II multi-drug metabolizing enzymes, such as CYP2D6, 3A4, and UGTA1, were reported to act as immunotargets in a subset of autoimmune hepatitis and hepatic autoimmunity. However, it is uncertain whether glutathione S-transferase (GST) A1-1, one of the phase II multi-drug metabolizing enzymes, is also an immunotarget in autoimmune hepatitis. So, in the present study, we investigated the frequency and significance of anti-GST A1-1 in sera from patients with autoimmune hepatitis. A total of 74 serum samples from patients with autoimmune hepatitis were examined in the present study. As controls, 20 serum samples from patients with primary biliary cirrhosis, 10 serum samples from patients with primary sclerosing cholangitis, 40 serum samples from patients with liver cirrhosis type B and C, 32 serum samples from patients with systemic lupus erythematosus, and 20 serum samples from normal controls were used. Anti-GST A1-1 antibody was determined by immunoblotting using the recombinant full-length GST A1-1 protein as the antigen. The immunofluorescent staining pattern of anti-GST A1-1 was investigated using rat liver and kidney sections. We compared clinicopathologic findings between anti-GST A1-1-positive and -negative autoimmune hepatitis patients. Anti-GST A1-1 was detected in 12 (16%) of 74 patients with autoimmune hepatitis, however, it was not detected in any control serum samples except for two patients with primary biliary cirrhosis. The immunofluorescence staining pattern of anti-GST A1-1 was found to be unique and different from those of anti-mitochondrial antibody or anti-liver-kidney microsome type 1 antibody. Anti-GST A1-1 coexisted with other autoantibodies such as anti-nuclear or anti-smooth muscle antibodies, but did not coexist with anti-soluble liver antigen/liver pancreas. Anti-GST A1-1-positive autoimmune hepatitis patients had severe clinical features and a poor prognosis compared with anti-GST A1-1-negative patients. These findings suggested that despite the low frequency, anti-GST A1-1 might be the marker of an early progression in autoimmune hepatitis.