Immunomodulatory Vitamin D in Thalassemia (ThalTB)

This study was designed as a non-randomized, open label, intervention study and performed at the thalassemia clinic of the Hasan Sadikin General Hospital, Bandung, West Java, Indonesia. Vitamin D deficiency in the general population is common in Indonesia with a prevalence of 41% reported in one study1. Sixty children (aged 1 month to 15 years) diagnosed as major β-thalassemia confirmed by clinical and hemoglobin electrophoresis who regularly having blood transfusion at least once in a month controlled in the clinic, from March - May 2018 were recruited prospectively. In addition, children who had ferritin serum >1000 µg/L in the last three months were met criteria for enrollment. Children who had tuberculosis or co-infection (hepatitis B, hepatitis C, and cytomegalovirus) and sign of acute infection were not eligible for enrollment. Informed consent was obtained from parents or child's guardian. Vitamin D levels were measured before and after supplementation while identifying their vitamin D sufficiency status. Classification of vitamin D sufficiency were used according to The Endocrine Society Clinical Practice Guideline, which stated that the level of 25(OH)D of < 20 ng/ml was considered to be vitamin D deficiency whereas a 25(OH)D of 21-29 ng/ml was considered to be insufficient. Then, a sufficient vitamin D was considered when the concentration of 25(OH)D was 30 ng/mL or above.2 No healthy control was enrolled to test for variability in the laboratory tests over time in this study.

The intervention provided according to the participants' state of vitamin D sufficiency. vitamin D sufficient participants received 800 IU cholecalciferol (syrup containing 400 IU cholecalciferol per measuring spoon, Gracia Pharmindo, Indonesia) daily for 8 weeks, while those who had insufficient or deficient vitamin D level consumed 2000 IU daily. Compliance was systematically monitored using drug monitoring diary evaluated by researchers. Blood samples for the study objectives were taken at enrollment and after eight weeks of cholecalciferol supplementation during routinely scheduled visits to the clinic. The outcome measure was the change in the proportion of monocyte subsets and the expression of membrane-bound protein of monocyte consist of CD14, CD16, and HLA-DR.

All procedures were conducted in accordance with policies of the Faculty of Medicine, Universitas Padjadjaran and Hasan Sadikin General Hospital, Bandung, West Java, Indonesia. This study was approved by Health Research Ethics Committee of Medical Faculty Universitas Padjadjaran Bandung with approval number 50/UN6.KEP/EC/2018. All participants signed a written informed consent. All participants signed a written informed consent. This study was registered in clinicaltrial.gov