The frequency of deleterious alleles in TNFAIP3 was higher in the AIH subset without the DRB1 risk alleles than that with (P = 0.0052, OR 5.10, 95%CI 1.55-16.74).
Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens.
Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens.
To examine this question, genomic DNA from peripheral lymphocytes (n = 9) and liver (n = 1) of 10 patients with anti-LKM-1 antibody was analysed by Southern blot for genetic association studies between a particular CYP2D6 haplotype and autoimmune hepatitis.
Among the HLA DRB1 alleles, DRB1*0301 (20% vs 6.19%; P = 0.03), DRB1*1301 (15% vs 2.65%; P = 0.01), DRB1*14 (30% vs 11.5%; P = 0.02) and DRB1*1501 (40% vs 22.12%; P = 0.08) were increased in AIH patients when compared with the controls.
The detailed internal replication and parallel analyses allowed the observation of two of eight AIH cases carrying a rare allele genotype for a previously described AIH-associated gene (FTCD), plus multiple occurrences of known HLA-DRB1 alleles associated with AIH (HLA-DRB1-03:01:01, 13:01:01 and 7:01:01).
Recently, molecular analysis using polymerase chain reaction (PCR)-based DNA typing has revealed that susceptibility to type 1 AIH is primarily associated with the HLA class II DRB1 locus, which encodes a polymorphic β chain of the HLA-DR antigen.
Susceptibility for type 1 autoimmune hepatitis has been associated with the major histocompatibility alleles DRB1*0301, DRB3*0101, DRB1*0401, and DRB4*0103, whereas the DRB1*1501 allele may protect from the disease.
The DRB1*04:05-DQB1*04:01 haplotype was significantly associated with AIH susceptibility (30% vs. 11%, P = 1.2×10(-10); odds ratio [OR] = 3.51) and correlated with elevated serum IgG (3042 vs. 2606 mg/dL, P = 0.041) and anti-smooth muscle antigen positivity (77% vs. 34%, P = 0.000006).
The present findings suggest that the gene or genes conferring susceptibility to AIH lie in the region centromeric to the HLA A locus between HLA C and DRB1.
DRB1*0301 and DRB1*0401 are confirmed as the principal susceptibility alleles for type 1 autoimmune hepatitis, and these data support the hypothesis that a lysine residue at position 71 of the DR beta-polypeptide chain may be the major risk factor.
Logistic regression analysis revealed that the HLA-DRB1*04:05 allele (P < 0.001, OR = 4.61) and rs9277534 (P = 0.004, OR = 1.67) were independently associated with AIH susceptibility. rs9277534G in the HLA-DP gene is an eQTL that affects gene expression and may contribute to AIH susceptibility.
Anti-liver-kidney microsome type 1 (LKM1) autoantibodies directed against the cytochrome P450 2D6 (CYP2D6) are considered specific markers of type 2 autoimmune hepatitis, but are also found in 5% of sera from patients chronically infected by hepatitis C virus (HCV).
The DRB1*04:05-DQB1*04:01 haplotype was significantly associated with AIH susceptibility (30% vs. 11%, P = 1.2×10(-10); odds ratio [OR] = 3.51) and correlated with elevated serum IgG (3042 vs. 2606 mg/dL, P = 0.041) and anti-smooth muscle antigen positivity (77% vs. 34%, P = 0.000006).
CD4 T cells from patients with type 2 AIH positive for the predisposing HLA allele DRB1*0701 recognize seven regions of CYP2D6, five of which are also recognized by CD8 T cells.
CD4 T cells from patients with type 2 AIH positive for the predisposing HLA allele DRB1*0701 recognize seven regions of CYP2D6, five of which are also recognized by CD8 T cells.