Effects of vitamin D and the antimicrobial peptide in asthma

Abstract

Background: Vitamin D modulates a variety of processes and regulatory systems including host defense, inflammation, and immunity. A connection between Vitamin D status and asthma has been considered. Vitamin D mediates innate immunity, particularly through enhanced expression of the human cathelicidin antimicrobial peptide (LL-37). Increased levels of high sensitive-C reactive protein (Hs-CRP) were found to be significantly associated with respiratory function impairment. Objective: to evaluate the relation between serum vitamin D, Hs-CRP and LL-37 levels and asthma. Study design: Thirty children (15 males and 15 females) with proven diagnosis of asthma (ages ranged from 3-13 years) were studied; they attended the pediatric department of Zagazig University Hospital in the year 2011. In addition, 30 age and sex matched apparently healthy children served as a control group. All children were subjected to history taking, clinical examination, laboratory investigations (CBC, CRP, ESR), determination of serum level of 25-hydroxyvitamin D (25 OHD) and plasma LL-37. Results: The study revealed a highly significant decrease in 25 OHD, LL-37 and a highly significant increase in Hs-CRP in children with asthma than in control group. There were a highly significant positive correlation between vitamin D and LL37 in patients' and control groups and a significant negative correlation between both 25OHD and LL37 and Hs-CRP in patients' group. High WBC count (specially neutrophils and lymphocytes), Hs-CRP level and low levels of hemoglobin, 25OHD and LL 37 in patient group were considered risk factors of asthma. Conclusion: Inappropriate concentration of vitamin D decreases the ability of the immune system to defend against infection through lowering LL-37 and elevated Hs-CRP which leads to occurrence and precipitation of asthma.

Keywords: Vitamin D- LL-37- asthma

Egypt J Pediatr Allergy Immunol 2012;10(2):101-107