Prevalence and clinical significance of immunoglobulin A antibodies against tissue transglutaminase in patients with diverse chronic liver diseases.

Abstract

The prevalence of celiac disease (CD) and the prevalence and clinical significance of anti-tissue transglutaminase (tTG) antibodies (tTGAbs) in a large series of patients with chronic liver diseases were assessed. We studied 738 patients (462 with chronic viral hepatitis, 117 with autoimmune liver diseases, 113 with alcoholic or nonalcoholic fatty liver disease, and 46 with other liver disorders) and 1,350 healthy controls (HC). Immunoglobulin A (IgA) tTGAbs were measured by enzyme-linked immunosorbent assay and a microsphere-based flow cytometric assay. Positive sera were investigated for IgA antiendomysial antibodies (EmA). IgA tTGAb-positive subjects were invited to undergo a small-intestinal biopsy and HLA-DQ allele typing. Four of 1,350 HC (0.3%) tested tTGAb(+) EmA(+) and underwent a biopsy (CD confirmation in all). Four of 738 liver disease patients tested tTGAbs(+) EmA(+) (0.54%; not statistically significant). Two were HCV infected (1.24%; not statistically significant), and two had transaminasemia of unknown origin. Forty-three patients tested tTGAbs(+) EmA(-) (5.8%; P<0.001 compared to HC). Inhibition experiments verified the existence of specific IgA anti-tTG reactivity. Twenty-six of 43 patients underwent a biopsy (all negative for CD). Binary logistic regression analysis revealed age (P=0.008), cirrhosis (P=0.004), alkaline phosphatase (P=0.026), and antinuclear antibodies (P=0.012) as independent risk factors for tTGAb reactivity among the patients. It was concluded that CD prevalence is the same in HC and patients with chronic liver diseases. The prevalence of tTGAbs is higher in hepatic patients compared to HC, but their specificity for CD diagnosis in this group of patients is low. tTGAbs in patients appear to be associated with the presence of autoimmunity, cirrhosis, and cholestasis, irrespective of the origin of the liver disease.