Effects of Anti-CD18 monoclonal antibody, R15.7, on the cardiopulmonary manifestations of group B streptococcal sepsis in piglets

We hypothesized that anti-CD18 monoclonal antibody, R15.7, a murine IgG(1) antibody which blocks leukocyte-endothelial cell adherence, might ameliorat e the cardiopulmonary manifestations of sepsis secondary to group B strepto cocci (GBS). Twenty-six anesthetized, mechanically ventilated newborn pigle ts received a continuous infusion of GBS (7.5 x 10(9) cfu/kg/min) and were randomly assigned to a treatment group receiving R15.7 (1 mg/kg i.v.) 15 mi n prior to GBS infusion or to a control group. Cardiopulmonary measurements , arterial blood gases and peripheral blood leukocytes were obtained over 1 20 min of R15.7 infusion. GBS infusion caused significant increases in pulm onary artery and systemic arterial blood (Psa) pressures, pulmonary vascula r (PVR) and systemic vascular (SVR) resistances, and PVR/SVR ratio with dec reases in cardiac output and stroke volume. R15.7-treated piglets maintaine d significantly higher Psa (p < 0.003), dynamic lung compliance (p < 0.04), PaO2 and pH (p < 0.05), and lower total lung resistance (p < 0.01) and PaC O2 (p < 0.04). A longer median survival time was observed in the treatment group (p < 0.01). These data suggest that administration of a CD18-blocking agent prolongs survival in a young animal model of GBS sepsis, possibly se condary to improved tissue perfusion, lung mechanics and acid-base status. Copyright (C) 2000 S. Karger AG, Basel.