Role of IL 6 as a Biomarker in the Diagnosis of Tuberculous Meningitis – A Systematic Review

Abstract

Background: Tuberculous meningitis (TBM) is the most common and serious form of central nervous system tuberculosis (TB) with high morbidity and mortality. Following the encounter of tubercle bacilli by microglial cells, inflammatory process sets in and series of cytokines are secreted such as tumor necrosis factor, interleukin-6 (IL6), and interferon γ. The following study was undertaken with the aim of systemically reviewing the diagnostic and prognostic evidence of IL6 in TBM. Methods: After a thorough search of databases for the articles with IL6 association in TBM published from 2001 onwards to September 2021. Articles were identified and assessed according to the inclusion and exclusion criteria. Excel spreadsheets were used for the extraction of data and analysis. Results: A total of 10 studies were included for review which focused on IL6 in the role of TBM diagnosis. All the age group persons of both sexes were included in the study. The experiment was conducted mostly in the developing countries. The range of measured IL6 values was very wide and difficult to interpret. Conclusion: TBM patients' IL 6 was higher than healthy controls in all the studies mentioned, but the results of cerebrospinal fluid IL6 and serum IL6 were less consistent. Due to a small number of prospective studies, it was not possible to analyze the IL6 cut-off value to diagnose TB. Further studies are required to provide information on IL6 as biomarker in the diagnosis of TBM.

Current State of Knowledge on Blood and Tissue-Based Biomarkers for Opisthorchis viverrini-induced Cholangiocarcinoma: A Review of Prognostic, Predictive, and Diagnostic Markers

“…IL-6 plasma levels (>64 pg/mL) showed 80% sensitivity and 90% specificity for detecting CCA with an 89% accuracy (95% CI = 85% to 93% [68]. However, the low diagnostic specificity of IL-6 is worth noting, as it has been proposed as an inflammatory marker for many conditions, including other cancers [70][71][72], virus [73] and bacterial infections [74,75].…”

Efficacy and prognostic value of peripheral blood CD4+ T cells and serum IL-6 and IL-8 in tuberculous meningitis

“…Cytokines, bioactive substances synthesised and secreted upon stimulation by immune or specific non-immune cells, play a critical role in the immune response following MTB infection – interleukin-6 (IL-6) and interleukin-8 (IL-8) exhibit bidirectional immunomodulatory functions in TB [ 7 ]. Interleukin-8 can induce the infiltration of neutrophils, lymphocytes, and monocytes, fostering a localised inflammatory response that aids pathogen elimination.…”