title: The Hidden Function of Vitamin D.
abstract: OBJECTIVE
  There are no reports regarding the influence of vitamin D on thymosin ß4 and the cluster of differentiation CD4 levels which are important for maintaining a healthy immune system. Consequently, we aimed to explore this relationship through a study.
  
  
  METHODS
  The study was carried out on 35 subjects, screened for 25-hydroxy vitamin D[25 (OH) D] using ELISA method and they were divided into two groups: Group 1 consists of 10 healthy subjects with sufficient vit. D level > 24.8 ng/ml. Group 2 consists of 25 subjects suffering, severely, from vitamin D deficiency at level < 11.325 ng/ml. Also, Thymosin ß4, CD4 and zinc levels were performed.
  
  
  RESULTS
  There were significant differences between the two groups in the concentration levels of thymosin β4, as the group 1 has shown higher levels (P = 0.005). Whereas, CD4 and zinc levels didn't show any significant difference between the two groups. At the same time, a significant positive correlation has been observed between vitamin D, thymosin β4, and CD4 at (r = 0.719; P = 0.001), and (r = 0.559, P = 0.001) respectively.
  
  
  CONCLUSIONS
  We concluded that vitamin D may be an essential factor that influence or determine the level of thymosin β4. This study is the first that focused on demonstrating that sufficient level of vitamin D may have the ability to influence the thymic hormone thymosin β4 levels. Further studies on large scale of subjects are needed to explore the positive correlation we had found between vitamin D and thymosin β4 and CD4.
authors.affiliation: Medical Physiology Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Hiba
authors.initials: H
authors.lastname: Sibaii
authors.affiliation: Medical Physiology Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Salwa Refat
authors.initials: SR
authors.lastname: El-Zayat
authors.affiliation: Child Health Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Azza Abd
authors.initials: AA
authors.lastname: El-Shaheed
authors.affiliation: Child Health Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Nermine N
authors.initials: NN
authors.lastname: Mahfouz
authors.affiliation: Child Health Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Sara F
authors.initials: SF
authors.lastname: Sallam
authors.affiliation: Medical Physiology Department, National Research Centre, Medical Division, 33 El-Bohouth Street, Dokki, POB:12311, Cairo, Egypt.
authors.forename: Marwa H
authors.initials: MH
authors.lastname: El Azma
keywords: Vitamin D; immunity; thymosin beta-4