Serum level of cathelicidin LL-37 in patients with active tuberculosis and other infectious diseases.
Majewski. K K; Agier. J J; Kozłowska. E E; Brzezińska-Błaszczyk. E E
Key Findings
- TB patients showed significantly higher serum LL‑37 than patients with Gram‑positive or Gram‑negative pneumonia and healthy controls.
- No meaningful correlation was found between LL‑37 levels and CRP or white‑blood‑cell counts in TB patients.
- The results support a role for LL‑37 in defending against intracellular pathogens such as Mycobacterium tuberculosis.
Practical Outcomes
- For biohackers, the main takeaway is that LL‑37 appears to rise naturally during certain infections, hinting it could be a useful biomarker of immune activation. However, the study does not provide dosing guidelines, supplementation strategies, or direct ways to boost LL‑37, so it offers limited immediate actionable steps for health optimization.
Summary
The study found that people with active tuberculosis have higher blood levels of the natural antimicrobial peptide LL‑37 compared to people with regular bacterial pneumonia or healthy folks. This suggests LL‑37 is part of the body’s defense, especially against infections that live inside cells, but the research didn’t link LL‑37 levels to standard inflammation markers like CRP or white‑blood‑cell count.
Abstract
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.
Study Information
pubmed
2017