GENETIC DISTINCTIONS BETWEEN TYPE-1 AND TYPE-2 AUTOIMMUNE HEPATITIS

Objectives: Our aim was to determine whether alleles affecting suscept ibility to type 1 autoimmune hepatitis in the United States occur as c ommonly in German patients with type 2 disease. Methods: DNA specimens from 12 German patients with type 2 autoimmune hepatitis were tested for class II alleles of the major histocompatibility complex by polyme rase chain reaction using sequence specific primers. Eighty-six Americ an patients with type 1 disease and 102 Caucasoid normal subjects from the United States were tested in a similar manner. Results: American patients with type 1 autoimmune hepatitis had DRB103 alleles more com monly than the German patients with type 2 disease (51% vs 17%, p = 0. 03) and DRB10301 occurred more frequently in the type 1 patients (51% vs 17%, p = 0.03). The frequency of DRB104 alleles was also higher i n the type 1 patients after exclusion of the DR103 alleles (64% vs 20 %, p 0.01). In contrast, patients with type 2 disease more commonly ha d DRB107 (p = 0.003), DRB1*15 (p = 0.004), and DQB1*06 (p = 0.0004). DRB107 (p = 0.005), DRB4*01 (p = 0.03), and DQB1*06 (p = 0.03) also o ccurred more frequently in the type 2 patients from Germany than in th e normal subjects from the United States, although none of these frequ encies were statistically significant by an adjusted p value. Conclusi ons: German patients with type 2 autoimmune hepatitis do not have the same susceptibility alleles as American patients with type 1 disease. Regional differences in prevalence may reflect the genetic profiles of the populations at risk.