Abstract
Low vitamin D (vitD3) is one of the most common nutritional deficiencies in the world known to be associated with numerous medical conditions including infections such as tuberculosis (TB). In this study, vitD3 status and its association with the antimicrobial peptide, human cathelicidin (LL-37), was investigated in Ethiopian patients with different clinical forms of TB. Patients with active TB (n = 77) and non-TB controls (n = 78) were enrolled in Ethiopia, while another group of non-TB controls (n = 62) was from Sweden. Active TB included pulmonary TB (n = 32), pleural TB (n = 20), and lymph node TB (n = 25). Concentrations of 25-hydroxyvitamin D3 (25(OH)D3) were assessed in plasma, while LL-37 mRNA was measured in peripheral blood and in samples obtained from the site of infection. Median 25(OH)D3 plasma levels in active TB patients were similar to Ethiopian non-TB controls (38.5 versus 35.0 nmol/L) and vitD3 deficiency (<50 nmol/L) was common in both groups (73%). Ethiopians (low latitude) had significantly lower 25(OH)D3 levels compared with Swedish non-TB controls (51.0 nmol/L, high latitude), but vitD3 status was not affected by tuberculin-positivity or HIV infection. Patients with local lymph node TB had significantly higher 25(OH)D3 levels compared with pulmonary TB patients (48.0 versus 29.0 nmol/L). Moreover, plasma 25(OH)D3 levels correlated with local LL-37 expression in granulomatous lesions in TB infected lymph nodes. Instead, systemic LL-37 mRNA expression in blood cells was elevated compared with the site of infection in pulmonary and pleural TB. Low vitD3 status may be associated with an enhanced peripheral expression of LL-37 in patients with intrathoracic TB that could result from chronic inflammation.
Highlights
Tuberculosis (TB) is an ancient disease, it continues to be an enduring danger to society and remains the main cause of death from infectious diseases worldwide [1]
pulmonary TB (PTB) was confirmed by a positive Mycobacterium tuberculosis (Mtb) culture of bronchoalveolar lavage (BAL), while pleural TB was confirmed by typical cyto- and histopathology of pleural fluid and biopsy samples and lymph node TB (LNTB) was confirmed by typical histopathology of lymph node biopsy samples
Patients with LNTB had higher 25(OH)D3 levels in plasma compared to PTB and pleural TB, which correlated with increased expression of LL-37 mRNA at the site of Mtb infection in the lymph nodes
Summary
Tuberculosis (TB) is an ancient disease, it continues to be an enduring danger to society and remains the main cause of death from infectious diseases worldwide [1]. The susceptibility to Mycobacterium tuberculosis (Mtb), the causative agent of TB, as well as the course of TB disease is affected by both host- and bacteria-specific factors. The active form of vitD3 is a steroid hormone with immunomodulatory properties and vitD3 deficiency (VDD) has been associated with impaired control of Mtb infection [2,3]. Due to the importance of UVB light for the production of vitD3 , VDD is subjected to seasonal variations [5,6]. It has been observed that VDD, defined as the concentration of 25-hydroxyvitamin D3 (25(OH)D3 ) below 50 nmol/L [7], was more common in dark-skinned people as strong skin pigmentation absorbs UVB sunlight and decreases the production of vitD3 in the skin [8]. It has been reported that ethnicity was associated with a higher susceptibility to active TB [3,9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
