Response of CAPD patients with a high incidence of peritonitis to intraperitoneal immunoglobulin therapy

This study has demonstrated that in the majority of high-peritonitis-incidence (PI) CAPD patients the defective opsonic activity levels in the peritoneal dialysis effluent (PDE) are restored for 3 weeks by a 12 g IP injection of immunoglobulins (Ig). Further studies showed that in a minority of high-PI CAPD patients who also had low PDE IgG and opsonic activity levels, IP Ig therapy did not significantly reduce the PI. To evaluate this phenomenon we utilized this therapy in 20 high-PI CAPD patients undergoing IP Ig therapy for an average of 24 months daily for 3 weeks (12 g every 3 weeks) and analyzed: 1) PDE IgG levels; 2) PDE opsonic activity; 3) peritoneal macrophage (PM0) membrane-bound IgG; 4) PDE Interleukin-1 (IL-1) levels; 5) PM0 membrane Fc receptor number. The results showed that in the 15 patients in whom Ig therapy reduced PI, there were long-lasting increases in the PDE IgG, opsonic activity and IL-1 levels, as well as a normal PM0 Fc receptor number and PM0 reversibly bound infused Ig. Conversely, the five patients in whom the IP Ig did not reduce the PI showed only transient increases in PDE IgG and opsonic activity levels, no PDE IL-1 increase, and the PM0 were deficient in Fc receptors and, therefore, unable to take up the infused Ig. We conclude that in high-PI CAPD patients there are different peritoneal immune defense abnormalities and that their identification is, therefore, important for the correct choice of therapy to improve these defects.