Plasma zinc levels inversely correlate with vascular cell adhesion molecule-1 concentration in children with sickle cell disease

Zinc deficiency has been implicated in impaired cell-mediated immunity of children with sickle cell disease (SCID). However, its influence on the expression of vascular cell-adhesion molecule-1 (VCAM-1) on endothelial cells, a protein involved in vasoocclusion, has not been previously investigated. We therefore measured (soluble) sVCAM-1 and zinc in 76 SCD children and 96 non-SCD children, mean age 7.73 years and 11.24 years, respectively. Although mean zinc levels of both groups were within the normal range (approximate to 14.5 mu mol/l), 14.5% of SCD and 11% of non-SCD children (without inflammation) had levels below normal (10.7 pmol/L). Mean sVCAM-1 concentrations of SCD children (837 mu g/l) were significantly higher than those of controls (627 mu g/l) (p < 0.001). Differences persisted after taking into account age, hemoglobin phenotype, and inflammation (alpha-lacid glycoprotein > 1 g/l and C-reactive protein > 10 mg/l). sVCAM-1 negatively correlated with serum (r= -0.444) and red blood cells zinc r=-0.242, p < 0.05) but not with acute-phase proteins. Mean sVCAM-1 tended to be higher in SCD children with than in those without a history of a health problem (infection, pain crisis or were transfused; not significant). Data suggest that zinc may modulate the clinical status of SCD children through VCAM-1 expression, and zinc supplementation may be beneficial in these patients.