YKL-40 in hemodialyzed patients with and without cardiovascular complications – The enhancement by the coexistence of the seropositivity against hepatitis C virus infection

Background YKL-40 is a new biomarker of inflammation, which is expressed by several cell types of the immune system. The aim of the present study was to evaluate plasma YKL-40 levels in hemodialysis (HD) patients and to establish its potential role as a new inflammatory biomarker of cardiovascular disease (CVD) in this population. Methods YKL-40 and two other inflammatory markers: high sensitivity C-reactive protein (hsCRP) and neopterin levels were measured in 70 HD patients both with and without CVD and in 38 healthy controls. Results Median YKL-40, hsCRP and neopterin levels were significantly elevated in HD patients, particularly those with CVD, compared to controls. YKL-40 was no associated with hsCRP, but it is strongly and independently associated with plasma neopterin levels in HD patients. The coexistence of the seropositivity against hepatitis C virus (anti-HCV) infection increased both YKL-40 and neopterin levels in these patients. This effect was particularly seen in subjects with CVD. Moreover, high neopterin levels were exclusively associated with anti-HCV seropositivity, whereas hsCRP values were only associated with the presence of CVD. Conclusions This study indicated for the first time that plasma YKL-40 level is increased in HD patients, especially in those with CVD, and it is independently associated with neopterin – an biomarker of monocyte/macrophage activation. There was no association between YKL-40 and hsCRP, the common indicator of an inflammatory state. Moreover, the coexistence of anti-HCV seropositivity had an important impact on plasma YKL-40 levels in HD patients particularly those with cardiovascular complications.