Internal Medicine Staff Veterinarian University of California, Davis Davis, CA, United States
Abstract:
Background: Serum Immunoglobulin G (IgG) is a marker of auto-immune hepatitis in humans and could have application in dogs with Immune-mediated Chronic Hepatitis (ICH). Hypothesis/
Objectives: Evaluate the utility of serum IgG to 1) differentiate ICH from Copper-Associated Chronic Hepatitis (CAH) and 2) monitor treatment response in dogs with ICH. Serum IgG was expected to be elevated in ICH dogs and decrease with treatment. Animals: Nineteen client-owned dogs with ICH and 15 dogs with CAH.
Methods: Dogs were prospectively diagnosed with ICH or CAH based on histologic criteria and treated for 6 months. Dogs with ICH were treated with cyclosporine ± copper-restricted diet if hepatic copper was ≥ 1000 µg/g dw. Dogs with CAH were treated with D-penicillamine and a copper-restricted diet. Serum IgG was measured using a radial immunodiffusion kit at baseline, 1, 3, and 6 months into treatment. A Wilcoxon-rank sum test compared IgG at baseline between dogs with ICH and CAH. A mixed effects model on log transformed data with Tukey’s pairwise comparisons evaluated IgG at baseline compared to each timepoint during treatment.
Results: Serum IgG (mg/dL) [median(Q1-Q3)] was not significantly different at baseline between dogs with ICH [2680 (2028-3176)] and CAH [2197 (1952-4324)] (p = 0.84). Serum IgG minimally increased from baseline to 6 months (p = 0.047) in dogs with ICH and did not change during treatment of CAH (p = 0.29). Conclusions and Clinical Importance: Serum IgG was not a useful marker to diagnose or monitor dogs with ICH.
