Chitotriosidase activity in plasma and mononuclear and polymorphonuclear

In the general population, about 5% of individuals are homozygotic and 35% are heterozygotic carriers for chitotriosiclase (ChT) deficiency. Activated macrophages are considered to be the main source of plasma ChT activity, which permits the biochemical characterization of homozygote deficients. However, in the case of detecting heterozygotic carriers, the results are often inconclusive. The activities of ChT in plasma and mononuclear (MN) and polymorphonuclear (PMN) leukocytes were determined in 169 control subjects (72 males and 97 females) with a mean age (+/- SD) of 47.5+/-9.7 years (range 18-96 years). The specific enzyme activity was in PMN leukocytes >MN leukocytes >plasma, with a highly significant partial correlation being found between the activities of ChT in plasma and PM leukocytes (r=0.578, P<0.001). A significant correlation was found between the age of the patients studied and plasma ChT activity (r = 0.568, P < 0.001). No significant correlation was found for enzyme activities in M (r=0.105) or in PM leukocytes (r=0.043). The results obtained suggest that, in normal physiological conditions, PMN leukocytes may secrete ChT to the plasma. Although the activities of ChT in M and PMN leukocytes are not affected by demographic factors, it is not possible to use them for the biochemical detection of ChT-deficient heterozygotic carriers. (C) 2003 Wiley-Liss, Inc.