Clinical Observations, Plasma Retinol Concentrations, and In Vitro Lymphocyte Functions in Children With Sickle Cell Disease.

BACKGROUND

Children with sickle cell disease (SCD) often have infections, growth deficits, and impaired immunity, problems that also are observed in individuals with a vitamin A deficiency (plasma retinol concentration <20 μg/dL). The goal of this study was to investigate the association between vitamin A, health status, and the in vitro immune function of children with SCD.

METHODS

Fifty-nine children (40 SS, 11 SC, and 8 Sβthalassemia [Sβthal] hemoglobin genotypes) 9 months to 18 years old were investigated for plasma levels of retinol, retinol binding protein, C-reactive protein, alpha-1-acid glycoprotein, lymphocyte proliferation, and interleukin (IL)-2 activity in supernatant of phytohemagglutinin-treated lymphocytes.

RESULTS

The plasma retinol concentrations of children with SCD (mean 57.6 μg/dL, range 4.6-116 μg/dL) were not different from those of 21 normal individuals (mean 62 μg/dL, range 28.7-162 μg/dL). Plasma retinol concentrations did not vary by hemoglobin genotype but were lower in boys than in girls (P < 0.05) and were also lower in children with inflammation (P = 0.1). Seven children (11.9%) (6 HbSS, 1 HbSβ0thal) were vitamin A-deficient, and 9 children (15.3%) had suboptimal vitamin A status (plasma retinol concentration of 20-29 μg/dL). Children with vitamin A deficiency had slightly lower height (P = 0.09) and weight mean percentiles, lymphocyte proliferative responses, and IL-2 activity (P > 0.1), but higher means of C-reactive protein (P = 0.05), pain crisis episodes and inflammation (P = 0.1), and health scores (P > 0.1) than children who were not vitamin A-deficient. Lymphocyte proliferative responses negatively correlated with health score, pain crisis episodes, and blood units received, but positively correlated with retinol binding protein (P < 0.05 to P = 0.1).

CONCLUSION

Identification and correction of suboptimal vitamin A status in children with SCD may improve immunity and attenuate certain health complications associated with this disease.