Serum antibodies against double-stranded DNA in chronic active hepatitis: an index of drug-induced liver disease?

Idiosyncratic liver toxicity of nonsteroidal antiinflammatory drugs: molecular mechanisms and pathology

This review explores the clinical hepatic pathology associated with the use of nonsteroidal antiinflammatory drugs (NSAIDs), possible cellular and molecular mechanisms of injury, and future challenges. NSAIDs comprise a group of widely used compounds that have been associated with rare adverse reactions in the liver, including fulminant hepatitis and cholestasis. These reactions are idiosyncratic, mostly independent of the dose administered, and host-dependent. The mechanisms responsible for the initiation and perpetuation of NSAID-induced hepatotoxicity remain poorly understood and have been largely inferred from clinical manifestation. A mounting body of evidence, however, indicates that many acidic NSAIDs are metabolized to reactive acyl glucuronides that can form covalent adducts with plasma proteins and hepatocellular proteins. In hepatocytes cocultured with lymphocytes, these NSAID-altered proteins can become antigenic. Thus, long-lived, drug-altered proteins may act as immunogens and produce cytotoxic T-cell-mediated or antibody-dependent, cell-mediated toxicity in susceptible patients. Alternatively, individual abnormalities in metabolism or disposition of some NSAIDs may lead to the formation or accumulation of toxic metabolites. Additional work with transgenic animal models is needed to permit better understanding of the general and specific risk factors involved in the pathogenesis of the idiosyncratic liver injuries related to NSAIDs and other drugs.

Pathology of chemically induced chronic active hepatitis in mice

Female Swiss mice were treated for 24 weeks, with 3-hydroxy-4-pyrone (Py) added to their powdered diet at 0.5% (wt/wt), and the effects of this agent on the liver were examined. Serum transaminases (especially GPT) rose continuously, while the GOT/GPT ratio remained at approximately 1.0 throughout the study period. The characteristic changes found from 8 weeks onward were piecemeal necrosis and bridging necrosis of the hepatocytes with dense lymphocytic infiltration. Proliferation of collagen fibers in the portal tracts and formation of narrow fibrous septa dividing the lobules into pseudolobules were also noted from 12 weeks onward. A large number of the infiltrating lymphocytes were identified as T cells by immunohistochemical and electron microscopic studies. These lymphocytes often surrounded or were closely attached to degenerating hepatocytes. Focal apoptosis and necrosis accompanied by a granulomatous reaction of the centrilobular hepatocytes were noted as early changes in the liver. Our findings indicate that the hepatic changes produced in mice by long-term Py administration have characteristics in common with those of human chronic active hepatitis. Immunological cytotoxic mechanisms, especially T cell-mediated ones, appear to play an essential role in the development of hepatic lesions in this murine model of chronic active hepatitis.

Subacute hepatic necrosis induced by piroxicam

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Measurement of serum DNA binding in chronic active hepatitis and systemic lupus erythematosus using the Farr assay

Antibodies to double-stranded DNA (dsDNA), generally regarded as highly specific for systemic lupus erythematosus (SLE), have also been reported in chronic active hepatitis (CAH). Using the Farr assay and E. coli DNA, fractionated by benzoylated-naphthoylated-DEAE cellulose chromatography into dsDNA and dsDNA containing single-stranded regions, we compared the serum DNA binding of CAH and SLE patients. Although CAH sera were found to have dsDNA binding significantly above the normal control group such binding was of low level and we could find no evidence of markedly elevated dsDNA binding in CAH. However 12 of the 20 CAH sera studied did bind preferentially to dsDNA containing single-stranded regions suggesting the presence of anti-single-stranded DNA antibodies. We conclude that the description of elevated anti-dsDNA antibodies, as measured by the Farr assay, in CAH is due to the interaction of anti-single-stranded DNA antibodies or other serum components with single-stranded DNA contaminating dsDNA preparations.