Increased Bacterial Translocation and Impaired Immune Response after Transfusion of Allogeneic Leukocytes

Abstract

It has previously been shown that in burned mice transfusion with whole blood increases septic mortality and decreases the ability of the host to kill translocated bacteria. To determine which hematic component contributes to this adverse effect, we studied the individual impact of transfusion with blood leukocytes (WBC), erythrocytes (RBC) or plasma on microbial translocation, bacterial clearance and mortality rate. Blood from C3H/HeJ mouse was separated into WBC, RBC and plasma. These components were transfused individually into Balb/c mice. Controls received sterile saline. Five days posttransfusion, all Balb/c mice underwent a 20% burn and gavage with 1 × 10¹⁰ relabeled Escherichia coli. Mortality was observed for 10 days. Four additional groups, receiving the same treatment as above, were sacrificed at 4 h postburn and mesenteric lymph nodes, liver, kidney, spleen and blood were harvested aseptically. For each tissue quantitative colony counts, residual radioactivity and percentage of bacteria remaining alive were calculated. Mytotic responses of splenic lymphocytes to PHA, concanavalin A, PWM mitogens and PGE₂ production by splenic macrophages were also determined. The WBC group showed a higher degree of ¹⁴C E. coli translocation, higher percentage of viable bacteria in the tissues and higher mortality comparted to all other groups. Moreover, in the WBC group the proliferation of splenic lymphocytes and the PGE₂ production were consistently increased. Therefore, transfusion of allogeneic leukocytes is associated with enhanced translocation, decreased clearance of translocated bacteria, remarkable production of PGE₂, activation of splenic lymphocytes and increased mortality.