Changes in inflammatory markers in patients treated for Buruli ulcer and their ability to predict paradoxical reactions.

Mycobacterium ulcerans causes Buruli ulcer, the third most frequent mycobacterial disease after tuberculosis and leprosy. Transient clinical deteriorations, known as paradoxical reactions, occur in some patients during or after antibiotic treatment. We investigated the clinical and biological features of PRs in a prospective cohort of BU patients from Benin including forty-one patients. Neutrophil counts decreased from baseline to day 90 and IL-6, G-CSF and VEGF were the cytokines displaying a significant monthly decrease relative to baseline. Paradoxical reactions occurred in 10 (24%) patients. The baseline biological and clinical characteristics of the patients presenting PRs did not differ significantly from those of the other patients. However, the patients with PRs had significantly higher IL-6 and TNF-α concentrations on days 30, 60 and 90 after the start of antibiotic treatment. The absence of a decrease in IL-6 and TNF-α levels during treatment should alert clinicians to the possibility of PR onset.