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.