HLA-DQ associations in type 1 autoimmune hepatitis

Spontaneous lupus-like syndrome in HLA-DQ2 transgenic mice with a mixed genetic background

To investigate the role of HLA-DQ2 in the pathogenesis of associated immune disorders, we generated transgenic mice that expressed HLA-DQ2 in the absence of endogenous murine class II molecules (AE(0)DQ2). These AE(0)DQ2 mice with a mixed genetic background spontaneously developed skin lesions on their ears, whereas control AE(0)DQ6 genotype control mice (also with a mixed genetic background) did not. The skin lesions were characterized by deep subepidermal blistering with hydropic degeneration and lymphoid infiltration in the subepidermal area as determined by histopathology. Immunofluorescence analysis revealed thick band-like granular deposition of IgG, IgM, and a thin band of IgA deposition along the basement membrane. AE(0)DQ2 mice also developed significant and progressive hematuria and proteinuria as compared with the AE(0)DQ6 mice (p < 0.05). Histopathology showed immune complex deposits in the glomeruli of AE(0)DQ2 mice. Immunofluorescence analysis showed progressive mesangial and capillary wall deposition of IgA, IgM, IgG and C1q in the kidney. With electron microscopy, the deposits showed a 'fingerprint' substructure; and tubuloreticular structures were identified within endothelial cells. Conversely, these changes were not observed in AE(0)DQ6 mice. Serum anti-double stranded (ds)DNA IgM and IgG levels were also significantly elevated among AE(0)DQ2 mice compared with AE(0)DQ6 mice (p < 0.001). In conclusion, AE(0)DQ2 mice spontaneously develop an autoimmune lupus-like syndrome and are useful model for this disease. It remains to be determined whether genetic admixture played a role in the development of this systemic lupus erythematosus-like syndrome in HLA-DQ2 transgenic mice. Lupus (2010) 19, 815-829.

Significant association of HLA-DQ5 with autoimmune hepatitis in Taiwan

Genetic predisposition is known to be an important etiopathogenic factor of autoimmune hepatitis (AIH). HLA antigens associated with AIH have been well studied in Western countries and Japan, but there is no HLA typing data of AIH patients in Taiwan. We therefore investigated HLA phenotypes and their association with AIH patients and compared the results with those of normal subjects and patients with chronic liver disease. Group 1 consisted of 22 AIH patients. All were born in Taiwan with no history of blood transfusion. Group 2 consisted of 19 chronic liver disease patients. Group 3 consisted of 81 unrelated healthy subjects who were normal blood donors. All three groups were tested for HLA phenotypes (HLAA, B, C, DR, DQ) using the polymerase chain reaction-sequence specific probe method. The statistical method used was Fisher's exact test. We found that HLA-DQ5 was significantly more frequent in the AIH group compared to the control group (RR, 2.03; p = 0.034). Low frequency of A1 (n = 2/22), B8 (n = 1/22) and DR3 (n = 0/22) were noted compared to results from the West; only HLA-DR4 showed a higher rate in our AIH patients (n = 8/22). This is a preliminary report of our study of HLA antigens in AIH patients. Further investigation to characterize AIH patients into HLA allelic subgroups is being done.

Identification of an association between HLA class II alleles and low antibody levels after measles immunization

This is the first large cohort study to report a genetic association between humoral antibody level after measles vaccine and the HLA class II genes. The WHO goal to eradicate measles world-wide magnifies the importance of data relating to the influence of immunogenetics on measles vaccine-induced antibody responses. We present here the analysis of 242 individuals who received one dose of measles-mumps-rubella-II (MMR-II) vaccine at the age of 15 months and were genotyped for HLA class II alleles. These subjects fit into one of three categories; 72 were classified as seronegative, 93 were seropositive and 77 were serohyperpositive. HLA-DRB1*03 (odds ratio (OR), 2.22) and HLA-DPA1*0201 (OR, 1.71) were significantly associated with measles vaccine seronegativity, while additional alleles provided suggestive evidence of association with seronegativity: DQA1*0201, DQB1*0201, and DQA1*0501. The alleles DRB1*03 and DQA1*0201 remained statistically significant after accounting for the effects of other alleles. These findings are crucial in designing both measles eradication by the use of vaccine, and future vaccines to be used in genetically heterozygous populations.

Cryptogenic cirrhosis: clinical characterization and risk factors for underlying disease

We characterized 70 consecutive patients with cryptogenic cirrhosis to assess major risks for liver disease. Each patient was reevaluated for past alcohol exposure, scored by the International Autoimmune Hepatitis (IAH) score and assessed for viral hepatitis risks and risks for nonalcoholic steatohepatitis (NASH). The results were compared with 50 consecutive NASH patients, 39 nonalcoholic patients age 50 and over with cirrhosis from hepatitis C, and 33 consecutive patients with cirrhosis caused by primary biliary cirrhosis (PBC). Among the cryptogenic group, 49 (70%) were female, and the mean age was 63 +/- 11 years. Although ascites and variceal bleeding were common, almost one half lacked major signs of complicated portal hypertension. A history of Type 2 diabetes mellitus and/or obesity was present in 51 (73%). Nineteen (27%) patients had a history of blood transfusions antedating the diagnosis of cirrhosis. No clinical or histological features distinguished this group from the other patients, and 14 (74%) of these had a history of obesity and/or diabetes. Nineteen of the remaining nontransfused patients had indeterminant IAH scores but were histologically and biochemically indistinguishable from the others. Twelve of these (63%) also had a history of obesity and/or diabetes. Both diabetes and obesity were significantly more common in the cryptogenic cirrhotic patients compared with the cirrhotic patients with PBC or hepatitis C. In contrast, the prevalence of obesity and diabetes was similar to the NASH patients who were, on average, a decade younger. Although there is some diversity that indicates more than one cause, our findings suggest that NASH plays an under-recognized role in many patients with cryptogenic cirrhosis, most of whom are older, type 2 diabetic and obese females.

HLA allele distribution distinguishes sporadic inclusion body myositis from hereditary inclusion body myopathies

We studied the HLA class II associations in patients with sporadic inclusion body myositis (s-IBM) and hereditary inclusion body myopathies (h-IBM) and attempted to distinguish these myopathies on the basis of HLA allele assignments. Forty-five patients, 30 with s-IBM and 15 with h-IBM, underwent HLA class II allele-specific typing using polymerase chain reaction sequence-specific primers for 71 alleles contained in the DRbeta1, DRbeta3-5, and DQbeta1 loci. In s-IBM, we found a high (up to 77%) frequency of DRbeta1*0301, DRbeta3*0101 (or DRbeta3*0202) and DQbeta1*0201 alleles. No significant association with alleles in the DR and DQ haplotypes was found among the 15 h-IBM patients. The strong association of prominent alleles with s-IBM, but not h-IBM, suggests that s-IBM is a distinct disorder with an immunogenetic background that differs from h-IBM.