Increased serum levels of tumor necrosis factor-α and interluekin-6 in adult Bahraini sickle cell disease patients with Hypovitaminosis d and low bone mineral density

Objective: To investigate serum levels and relationship between tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), bone mineral density (BMD) and vitamin D in Bahraini sickle cell disease (SCD) patients compared to healthy controls. Methods: Seventy patients with SCD followed at department of hematology at Salmaniya Medical Complex and 70 sex-matched healthy controls were included prospectively in this study. Serum levels were measured using ELISA kits for cytokines and UPLC-MS for vitamin D. BMD was estimated using Dual Energy X-ray Absorptiometry (DEXA). Osteopenia (T score < -1>-2.5) and osteoporosis (≤ -2.5) were diagnosed as per WHO criteria. Results: SCD patients had increased serum levels of TNF-α (56.72 pg/ml; range 27.43-98.93) compared to controls (39.49 pg/ml; range 27.56-119.95; p<0.0001). Our patients had increased serum levels of IL-6 (49.5 pg/ml; range 12.27-101.81) compared to controls ( 30.08 pg/ml; range 4-275; p=0.002). While, 94% of patients had low vitamin D, only 6% had optimal levels. However, 58% of patiens had abnormal BMD and 42% had normal BMD. A positive correlation between vitamin D and TNF-α (r=0.333, p=0.005) and vitamin D and CRP (r=0.265, p=0.027) were found, but not between vitamin D and BMD. Conclusions: The presence of low-grade inflammation in Bahraini SCD patients in steady-state is suggested by increased levels of proinflammatory cytokines and CRP. The cytokines (TNF alpha and IL-6) serum levels were associated with hypovitaminosis D. Vitamin D and BMD tests should be offered to all SCD patients for early intervention, if indicated.