Determination of serum levels of YKL-40 and hyaluronic acid in patients with hepatic fibrosis due to schistosomiasis japonica and appraisal of their clinical value

The objectives of this study were (i) to evaluate the serum levels of human cartilage glycoprotein 39 (YKL-40) and hyaluronic acid (HA) in people infected with Schistosoma japonicum, and (ii) to determine their clinical value. A total of 563 people were subjected to ultrasonography, and 60 patients were identified with either mild (n = 30) or severe (n = 30) hepatic fibrosis. In addition, 28 healthy subjects were included as controls. Blood sera of these 88 people were examined with regard to the levels of YKL-40 and HA. The former was measured by enzyme-linked immunosorbent assay, and serum HA was determined by a commercially available radioimmunoassay method. On the basis of the ultrasonographic investigations, HA levels in normal, mild, and severe cases of hepatic fibrosis were 83.0 ± 35.7, 216.1 ± 77.9 and 212.6 ± 80.9 μg/ml, respectively. When the same sera were tested for YKL-40, 49.0 ± 10.4, 92.3 ± 18.5 and 172.1 ± 35.9 μg/ml, respectively, were recorded in the three groups. Thus, the serum levels of YKL-40 are not only increased in patients infected with S. japonicum but they are also correlated with the stage of hepatic fibrosis. In conclusion, it appears that YKL-40 is more sensitive than HA in measuring the degree of hepatic fibrosis due to schistosomiasis, which warrants further investigation.