Markers of Systemic Inflammation in Horses with Heaves.

Background Systemic inflammation in horses with heaves is poorly characterized. Objectives To assess acute phase proteins ( APP) and inflammatory cytokine profiles in serum of healthy horses and horses with heaves. Animals Six healthy horses and 6 heaves-affected horses belonging to the University of Montreal. Methods Prospective, observational study. Healthy and heaves-affected control horses were exposed to a 30-day natural challenge with hay and straw to induce clinical exacerbation of heaves. Serum samples were obtained by venipuncture before ( T0) as well as after 7 ( T7) and 30 days ( T30) of stabling. Serum APP (haptoglobin, serum amyloid A protein [ SAA] and C-reactive protein [ CRP]) and cytokines ( IL-2, IL-4, IFN-α, IL-10, IFN-γ, and CCL-2) were measured using singleplex or multiplex ELISA. Results Serum haptoglobin concentrations were significantly higher in heaves-affected horses at all time points with no overlap with those of healthy controls. They were also significantly increased by antigen challenge in both controls ( T7) and horses with heaves ( T7 and T30). Serum SAA was detected more frequently in heaves-affected horses compared with healthy controls at T7. There was no difference in serum concentrations of CRP, IL-10, IFN-γ, and CCL-2 between groups, whereas IL-2, IL-4, and IFN-α remained undetectable in all samples. Conclusions and Clinical Importance In heaves, haptoglobin is a marker of both acute and chronic systemic inflammation, whereas high concentrations of SAA indicate acute inflammation. [ABSTRACT FROM AUTHOR]