ELEVATED PLASMA CHITOTRIOSIDASE ACTIVITY IN VARIOUS LYSOSOMAL STORAGEDISORDERS

Recently a striking elevation of the activity of chitotriosidase, an e ndo beta-glucosaminidase distinct from lysozyme, was found in plasma f rom patients with Gaucher type I disease (McKusick 230800). Plasma chi totriosidase originates from activated macrophages and this elevation is secondary to the basic defect in Gaucher disease. To investigate th e specificity of this phenomenon, we have investigated 24 different ly sosomal storage diseases. In 11 different diseases increased chitotrio sidase activity in plasma was found (in 28% of the patients). None of these diseases showed elevations as high as in Gaucher disease. Chitot riosidase was not significantly elevated in plasma from 20 different n on-lysosomal enzymopathies or in plasma from patients with infectious diseases associated with hepatomegaly. The results show that marked el evation of chitotriosidase activity in plasma appears to be specific f or Gaucher disease. The data further suggest that elevated levels of c hitotriosidase activity in plasma from patients with unexplained disea ses may be indicative for a lysosomal disorder.