Monitoring of inflammatory blood biomarkers in foals with Rhodococcus Equi pneumonia during antimicrobial treatment.
Authors: Deniz Ömer, Ekinci Gencay, Onmaz Ali Cesur, Derelli Fatih Mehmet, Fazio Francesco, Aragona Francesca, Hoven René van den
Journal: Journal of equine veterinary science
Summary
# Rhodococcus equi pneumonia in foals: tracking immune recovery through blood biomarkers Rhodococcus equi remains a significant cause of pneumonia and mortality in foals, yet monitoring immune response during treatment remains poorly characterised. Researchers tracked changes in complete blood cell counts, fibrinogen and key cytokines (interferon-alpha and gamma, interleukins 2 and 10) in clinical foal cases receiving standard azithromycin-rifampicin therapy over 14 days, sampling at baseline, day 7 and day 14. By day 14, white blood cell and neutrophil counts fell substantially (from 25.6 to 14.2 and 18.6 to 10.7 × 10³/ml respectively), alongside marked reductions in monocytes and fibrinogen concentration (539 to 287 g/dl), indicating resolution of the acute inflammatory response. Notably, interleukin-2 and IL-10 concentrations increased significantly during treatment, whereas interferon levels remained static—suggesting a shift towards immune resolution rather than interferon-mediated control. Whilst individual cytokine measurement alone appears of limited diagnostic value, the dynamic pattern of interleukin changes during treatment may provide useful adjunctive markers for assessing treatment response and innate immune recovery, potentially helping practitioners and researchers distinguish genuine clinical improvement from stalled infections warranting treatment modification.
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Practical Takeaways
- •Monitor WBC, neutrophil, monocyte counts and fibrinogen levels during azithromycin-rifampicin treatment as these markers show clear improvement by day 14 and may help assess treatment response
- •Rising IL-2 and IL-10 levels during treatment appear associated with clinical improvement, suggesting these markers may help practitioners evaluate whether the immune system is mounting an appropriate response
- •Individual interferon measurements alone are not reliable diagnostic or prognostic markers for R. equi pneumonia—focus on the pattern of multiple inflammatory markers rather than single values
Key Findings
- •Azithromycin-rifampicin treatment for 14 days significantly decreased WBC counts from 25.6 ± 6.7 to 14.2 ± 2.7 × 10³/ml and neutrophil counts from 18.6 ± 6.2 to 10.7 ± 3.1 × 10³/ml
- •Fibrinogen concentration decreased significantly from 539 ± 124 to 287 ± 26 g/dl between day 0 and day 14 of treatment
- •IL-2 and IL-10 concentrations increased significantly after treatment (P = 0.028 and P = 0.013 respectively), while IFN-α and IFN-γ showed no significant change
- •Interleukin activity patterns during treatment may indicate immune response amelioration but individual cytokine measurements have limited diagnostic potential