Effects of intravenous gamma immunoglobulins treatment on severe peritonitis in rats

Generalized purulent peritonitis is characterized by an early exposure of the immune system to a large number of bacterial antigens. The hypothesis that intravenous IgG treatment may improve the outcome of severe experimental peritonitis was studied.

Peritonitis was induced in rats by cecal ligation and perforation. Continuous intravenous fluid infusion, broad-spectrum antibiotics, and twenty-four hours treated forty rats after the induction of the disease they were re-operated and the perforated cecum was excised. Twenty of these animals received in addition specific rat IgG in two intravenous infusions (0.4 gr./kg), two and twenty four hours after the induction of peritonitis.

Elevated WBC counts and mild metabolic acidosis was found one day after the induction of peritonitis. IgG treatment was associated with lower WBC counts in the following days and with higher pH than in the control group (p < 0.05 for both parameters). All peritoneal cultures and 90% of blood cultures were positive 24 hours after the initial operation. These rates decreased in the following days and in the IgG treatment rats the peritoneal cavity and blood were sterile earlier than in the control animals (p < 0.05). Serum IgG was depleted in the control animals within 48 hours after the induction of peritonitis, while in the IgG treated animals its levels were remarkably elevated. IgG administration significantly improved the survival, which was 70% in the IgG treatment rats as compared to 40% in the control rats.

These results indicate that intravenous IgG has beneficial effects on severe experimental peritonitis.