Effect of plasma transfusion on serum amyloid A concentration in healthy neonatal foals and foals with failure of transfer of passive immunity.

Abstract

BACKGROUND: Anecdotal evidence suggests plasma transfusions increase serum amyloid A (SAA) concentrations in healthy neonatal foals making this marker of inflammation inappropriate for therapeutic decision making in such animals. HYPOTHESIS/OBJECTIVES: Administration of hyperimmune fresh frozen plasma (FFP) increases SAA concentration in healthy foals and in foals with failure of transfer of passive immunity (FTPI). ANIMALS: Eighty-six healthy foals. METHODS: Prospective cohort study. Foals <24&#x2009;hours of age receiving plasma transfusion for treatment of FTPI (serum immunoglobulin G [IgG] concentrations <8&#xa0;g/L; n&#xa0;=&#xa0;17) or as a preventative measure for Rhodococcus equi infection (IgG >8&#xa0;g/L; n&#xa0;=&#xa0;33) were enrolled. A healthy nontransfused group of foals (IgG >8&#xa0;g/L; n&#xa0;=&#xa0;21) also was included. Serum&#xa0;amyloid&#xa0;A concentration was determined before (t0h) and after (t24h) administration of FFP. Changes in blood SAA concentration were assessed using linear regression models. RESULTS: No statistical differences were found in SAA concentration at t0h or t24h among the 3 groups (P&#x2009;>&#x2009;.05, for all comparisons). The variation in SAA concentration before (t0h) and after (t24h) plasma transfusion showed that administration of FFP was not associated with the changes in SAA concentration (P&#x2009;>&#x2009;.05). An association between SAA concentration at t0h and at 24&#x2009;hours (P&#x2009;<&#x2009;.05) was identified, where foals with higher SAA concentration at t0h also had higher SAA concentration at t24h. CONCLUSIONS AND CLINICAL IMPORTANCE: Administration of FFP to newborn foals was not associated with changes in SAA concentration.