Relationship between serum 25-hydroxyvitamin D and inflammatory cytokines in paediatric sickle cell disease

Background. Alteration in the concentration of inflammatory cytokines may contribute to pathogenesis in sickle cell anaemia (SCA). Vitamin D may suppress pro-inflammatory cytokines and enhance anti-inflammatory cytokines. Objective: To compare steady state levels of pro-and anti-inflammatory cytokines of Nigerian SCA children with age-and sex-matched healthy controls, and determine the relationship with 25-hydroxyvitamin-D (25-OHD). Effects of three months of vitamin D supplementation on cytokines of SCA children with suboptimal 25-OHD were also evaluated. Methods: Serum 25-OHD, IL-113, 2, 6, 8, 11, 12, 13, 17, 18 of 95 SCA children and 75 matched controls were determined using HPLC. The 12 SCA children with suboptimal 25-OHD received 2000 IU of vitamin D daily for 3 months, and their post supplementation cytokines and 25-OHD levels were compared with the baseline values. Results: IL-2, 6, 8, 12, 17 and 18 were higher in SCA children than the controls (p <= 0.001), but no significant variation in IL-11 and 13 (p = 0.131 and 0.057 respectively). Patients with suboptimal serum 25-OHD had higher IL-6, 8 and 18 (p = 0.003, 0.010 and 0.002 respectively) and lower levels of IL-11 (p = 0.005). Significant positive treatment effects were observed: post-supplementation, serum 25-OHD increased by 23.3 ng/mL, p < 0.001; proinflammatory cytokines IL-2, 6, 8, 17 and 18 (p < 0.001) were reduced and anti-inflammatory cytokine IL-11 was increased, p < 0.001. Conclusions: Suboptimal 250HD is associated with enhanced levels of pro-inflammatory markers in children with SCA. Three months of daily vitamin D supplementation reversed the trend. Hence; Vitamin D supplementation may reduce the inflammatory milieu and serve as an anti-inflammatory agent in the management of SCA.