Effect of plasma transfusion on neutrophil function in healthy and septic foals.

The research investigated plasma transfusions in foals, specifically its effect on neutrophil function in healthy and septic newborn horses with less than optimal maternal immunity. The findings suggest that for healthy newborn horses, plasma transfusion does not improve neutrophil function and may be of uncertain benefit, but for septic foals, the procedure appears beneficial.

Introduction

Neutrophils are essential for fighting infections in the body. Their ability to devour harmful particles is known as phagocytosis, and the capacity to destroy them is the oxidative burst activity. The immune response, particularly in newborn animals that have sub-optimal passive transfer of maternal immunity, can be influenced by factors like plasma transfusion. This research aimed to assess the impact of plasma transfusion on these essential neutrophil functions in both healthy and septic (infection-prone) foals.

Research Methods and Subjects

• 16 foals with sub-optimal passive transfer of maternal immunity (identified by serum IgG, a type of antibody, levels < 8 g/L) were categorized as either healthy or septic and then given plasma transfusions.
• Sepsis condition was determined through positive bacterial cultures or a sepsis-score of 11 or higher.
• All participating foals received between 1 and 3 Liters of plasma to increase circulating IgG concentrations to >= 8 g/L.
• The study also evaluated the neutrophil function of seven healthy foals that were less than seven days old and already had the adequate circulating IgG concentration. These foals were evaluated once only.
• Neutrophil phagocytosis and oxidative burst activity were measured before and after the plasma transfusion at various time points – straight away post-transfusion, and at 12 hours, 24 hours, 48 hours, and 5 days following treatment.

Research Findings

• The plasma treatment substantially increased circulating IgG concentrations for both healthy and septic foals.
• In septic foals, significantly enhanced oxidative burst activity of neutrophils was observed 5 days following transfusion compared to immediate post-transfusion levels.
• A possible temporary decrease in phagocytosis was noted in neutrophils from healthy foals right after transfusion while an increase was observed in neutrophils from septic foals.
• Compared to their healthy mates, septic foals had consistently lower oxidative burst activity of neutrophils at all measured times. This was particularly notable 5 days after treatment.
• While serum IgG levels did not correlate with neutrophil phagocytosis, a correlation was detected with oxidative burst activity.

Conclusions

The study concludes that plasma transfusion appears to offer no particular benefits for healthy foals as it does not improve their neutrophil function. On the other hand, plasma transfusion appears to be beneficial for septic foals, where improved neutrophil function was observed post-treatment. The research thus provides valuable insights that may influence the treatment strategies for neonatal equine health, particularly those with reduced maternal immunity or sepsis.