Effect of Unmetabolized Folic Acid on Immunoinflammatory Markers in Sickle Cell Disease Patients Taking Folic Acid Supplementation

Folic acid (FA) supplementation in sickle cell disease (SCD) patients lead to accumulation of unmetabolized folic acid (UMFA) which might influence the level of cytokines and NK cell activity and thus trigger the crisis event. The aim of the study was to investigate the effect of UMFA levels on immuno-inflammatory markers in SCD patients taking FA supplementation. The cross-sectional study was conducted on 60 HbSS confirmed SCD cases with 22 crisis and 38 cases at steady state of 15-40 years age group. Serum FA, 5-Methyl Tetrahydrofolate (5-MTHF), Dihydrofolate reductase, Interleukin-6 (IL-6), Highly sensitive C-Reactive Protein (HsCRP), and natural killer (NK) cell activity were estimated. More than 50% of the study population depicted presence of UMFA. The median UMFA level was significantly elevated in crisis group (131.8 ng/mL) as compared to the steady state group (36.31 ng/mL) (p = 0.041). The median value of HsCRP was significantly higher in the crisis group (18.41 mg/L) than the steady state group (2.04 mg/L) (p = 0.003). Similarly, IL-6 was higher in crisis group (13.29 pg/mL) than steady state group (5 pg/mL) (p = 0.060). The median NK cell activity was 39.28 nmol/L in crisis group and 35.31 nmol/L in steady state groups (p = 0.889). In bivariate correlation analysis, UMFA showed a significant negative correlation with NK cell activity (r = - 0.638; p = < 0.001) and a positive correlation with IL-6 (r = 0.571; p = 0.001) and HsCRP (r = 0.237; p = 0.200). Accumulation of UMFA affect NK cell activity, thus influence the vulnerability for crisis state. Therefore, dosage modification for FA supplementation in SCD patients is suggested.