Cytokines for monitoring anti-tuberculous therapy: A systematic review

The ability to monitor response to therapy for tuberculosis (TB) and confirm adequate treatment would be a major advance. The low reversion rate of interferon-gamma based assays means that they are unlikely to be useful for monitoring therapy. Several exploratory studies have evaluated the diagnostic potential of cytokine biomarkers other than interferon-gamma for monitoring anti-tuberculous therapy. A systematic review of these studies was performed to identify the most promising candidate biomarkers. TNF-α, IL-2, IL-6, IL-10 and IL-12 were the most extensively investigated cytokines. There was significant heterogeneity between studies in relation to study design and laboratory methodology, complicating direct comparisons. There was marked variation between studies in the observed changes during treatment for many of the biomarkers. Further longitudinal studies in sufficiently large patient cohorts with rigorous methodology are needed to determine the true potential of individual cytokine biomarkers, or combinations, for monitoring TB treatment.