Status of cathelicidin IL-37, cytokine TNF, and vitamin D in patients with pulmonary tuberculosis.

Development of Mycobacterium tuberculosis (Mtb) infection depends on the ability of the host to elicit the protective immune response to the pathogen. Cathelicidin plays a role in antibacterial innate immunity mechanisms. This peptide contributes to the barrier function of respiratory epithelium and takes part in controlling pulmonary bacterial infections. LL-37 (leucine-leucine-37) is involved in host defense and innate immune response to mycobacterial infections, as well. This study aims to evaluate the serum concentrations of LL-37 in individuals with active pulmonary tuberculosis (TB) and to determine whether any correlations between peptide LL-37, tumor necrosis factor (TNF) and vitamin D serum levels exist. A total of 46 adults with pulmonary TB were recruited for the study. Sixty-one controls were randomly selected as control group. Serum concentrations of cathelicidin LL-37, vitamin D (25(OH)D), as well as TNF, were measured using an enzyme-linked immunosorbent assay (ELISA) kit. The mean (± SEM) level of LL-37 was significantly higher in the TB group (7.45±1.58) compared with healthy controls (1.41±0.22) (p less than 0.001). Mean serum concentration of TNF was significantly higher in the TB group (8.51±1.92) compared with healthy controls (2.69±0.19) (p less than 0.001). There was no significant difference in mean serum levels of vitamin D between healthy (26.10±1.74) and TB subjects (24.18±1.95). No correlations between LL-37, TNF, and vitamin D levels in patients with TB were observed. Our results indicated that serum levels of peptide LL-37 during TB is raised significantly, and this observation is compatible with the general view of the important role of this cathelicidin in defense mechanisms against Mtb infection.

Mast cells participate in chronic low-grade inflammation within adipose tissue.

Obesity is reckoned as one of the civilization diseases, posing a considerable global health issue. Evidence points towards a contribution of multitude immune cell populations in obesity pathomechanism and the development of chronic low-grade inflammation in the expanded adipose tissue. Notably, adipose tissue is a reservoir of mast cells which number in individuals with obesity particularly increased. Some of them tend to degranulation what generate secretion of strong pro-inflammatory and regulatory mediators, as well as cytokines/chemokines. Several lines of evidence suggest that mast cells are strictly associated with pro-inflammatory status in adipose tissue by their indirect impact on immune cell attraction and activation. Furthermore, mast cells affect adipose tissue remodelling and fibrosis by adipocyte differentiation, fibroblast proliferation and enhancing extracellular matrix proteins expression. This review will summarize current knowledge on mast cell features and their role in the development of chronic low-grade inflammation within adipose tissue.

Serum level of cathelicidin LL-37 in patients with active tuberculosis and other infectious diseases.

A growing body of evidence indicates the role of cathelicidin LL-37, a member of the antimicrobial peptide family, in host innate defense mechanisms. The important role of this peptide in infectious diseases is also suggested, however, to date, data relating to LL-37 expression in the course of bacterial infections are far from complete. Therefore, the aim of the present study was to determine LL-37 serum levels in adult patients with pulmonary tuberculosis (TB). For comparison, circulating LL-37 levels in patients with pneumonia induced by Gram-positive or Gram-negative bacteria species and in healthy subjects were evaluated. Fifty patients with pulmonary TB, 31 patients with pneumonia caused by gram-positive bacteria, 68 individuals with pneumonia caused by Gram-negative bacteria, and 61 randomly selected healthy subjects were enrolled in the study. Serum LL-37 concentration was measured using an enzyme-linked immunosorbent assay (ELISA). We established that the mean level of LL-37 was statistically significantly higher in TB patients than that in patients with Gram-positive bacteria-induced pneumonia (p < 0.001), in patients with Gram-negative bacteria-induced pneumonia (p < 0.001), and in healthy controls (p < 0.001). In patients with TB, no statistically significant correlations between serum LL-37 and CRP concentrations (r = -0.2042; p = 0.189) and between serum LL-37 concentration and WBC count (r = -0.1277; p = 0.414) were observed. Our observations clearly documented that cathelicidin LL-37 plays a role in defense mechanisms against infectious agents, and is particularly important when the infection is caused by an intracellular pathogen.