Verification of B-lymphocyte activating factor's involvement in the exacerbation of insulin resistance as well as an autoimmune response in patients with nonalcoholic steatohepatitis and patients with HCV-related chronic liver disease.

BACKGROUND: Ten to forty percent of nonalcoholic steatohepatitis (NASH) and HCV-related chronic liver disease (CLD-C) patients have antinuclear antibodies (ANAs). However, the relationship between autoimmune response and insulin resistance remains uncertain among those patients. The primary purpose of this study was to investigate whether or not ANA status was associated with the development of insulin resistance and obesity in NASH and CLD-C patients.

METHODS: Degrees of hepatic fibrosis and steatosis were evaluated by the classification proposed by Brunt et al. Obesity and insulin resistance were estimated by calculating body mass index and the value of homeostasis model of for assessment of insulin resistance (HOMA-IR), respectively. A revised scoring system was applied to the diagnosis of autoimmune hepatitis (AIH). Serum B-lymphocyte activating factor (BAFF) levels were determined, using an ELISA technique.

RESULTS: Ten of 25 (40%) NASH patients and 9 of 22 (41%) CLD-C patients had ANAs, though the titers were weak in most patients. Only one NASH patient met the category of "definite" AIH among the enrolled patients. Serum IgG levels were significantly higher in NASH and CLD-C patients with ANAs than in those without ANAs, and NASH and CLD-C patients with ANAs had significantly higher HOMA-IR values than those without ANAs (6.81 ± 3.36 vs. 4.00 ± 2.57, p = 0.0305, 3.01 ± 1.31 vs. 1.28 ± 0.50, p = 0.0011). CLD-C patients with ANAs had more advanced hepatic fibrosis and steatosis than those without ANAs, while ANA status was not associated with hepatic fibrosis or steatosis in NASH patients. Obesity was independent of ANA status in both subjects. Serum BAFF levels were significantly higher in CLD-C patients with ANAs than those in CLD-C patients without ANAs (1303 ± 268 vs. 714 ± 143 pg/ml, p = 0.0036). A close correlation between serum BAFF level and the HOMA-IR value was observed in CLD-C patients (r = 0.467, p = 0.0485).

CONCLUSION: Our data suggest that NASH and CLD-C patients with ANAs have more severe insulin resistance than those without ANAs. More advanced insulin resistance deriving from excessive BAFF production may result in severe hepatic fibrosis and steatosis in CLD-C patients with ANAs.