New aspects of liver abnormalities as part of the systemic mast cell activation syndrome.

Background/aims: This study was aimed at investigating the form and prevalence of liver involvement in patients with systemic mast cell activation syndrome, a possibly common subvariant of systemic mastocytosis. An attempt was made to shed light on potential mechanisms responsible for mast cell mediator-related liver abnormalities.

Methods: The methods used were clinical investigation, biochemical determination of cholesterol, transaminases and bilirubin in blood, determination of chitotriosidase by enzyme-linked immunosorbent assay technique, and quantitative reverse transcribed-polymerase chain reaction to determine chitotriosidase expression.

Results: An elevation of plasma cholesterol was detected in 75% of the patients; elevations of transaminases and bilirubin were determined in 40 and 36% of the patients respectively; hepatomegaly or morphological hepatic alterations were observed in 34%. Chitotriosidase level in blood as a surrogate parameter for Kupffer cell activation in the liver was unchanged. However, chitotriosidase expression in isolated mast cells was downregulated at the mRNA level.

Conclusions: Hypercholesterolaemia and liver abnormalities are frequently found in patients with the mast cell activation syndrome. Hence, the mast cell activation syndrome should be considered at an early stage as a possible cause of hypercholesterolaemia and of hepatic abnormalities of unknown reason. Mast cell activation may be indicated by a reduced expression of the enzyme chitotriosidase in blood-derived mast cells as well as by an increased plasma cholesterol level.