Background: YKL-40 is a glycoprotein secreted by various cell lines during inflammation and vascular dysfunction. Sickle cell disease (SCD) also involves inflammation and endothelial dysfunction processes. Thus, we aimed to assess the levels of YKL-40 in pediatric SCD patients.

Methods: We evaluated serum levels of YKL-40 in children with steady state SCD and those with vaso-occlusive crisis (VOC) episodes and compared them with healthy subjects.

Results: Overall, 33 children with SCD and 33 healthy controls participated in this study. Serum YKL-40 concentrations of children with steady state SCD were significantly higher than the concentrations found in the healthy controls (median [Q1-Q3]: 71.0 [53.3-133.3] vs. 43.6 [37.9-69.9] ng/mL, p=0.001). Seventeen of the 33 children with SCD (51.5%) had a VOC during the one-year follow-up period. Steady state and VOC episode YKL-40 did not significantly differ in children who were experiencing VOC during the one-year follow-up (77.6 [55.2-126.8] vs. 69.7 [49.3-100.0] ng/mL, p=0.381). During VOC episodes, children with SCD had significantly higher YKL-40 levels than the healthy controls (69.7 [49.3-100.0] vs. 43.6 [37.9-69.9] ng/mL, p=0.005). YKL-40 levels at steady state and during VOC episodes did not show significant correlation (p=0.955).

Conclusions: YKL-40 may have a potential role in the inflammation component of SCD. Circulating YKL-40 levels may be used to monitor chronic inflammation in SCD patients.