Role of opsonins in clinical response to granulocyte transfusion in granulocytopenic patients

Fifty febrile severely granulocytopenic patients were given four daily transfusions of 2.2 X 10 10 normal donor granulocytes. Twenty-three (46 percent) responded clinically, although both responders and nonresponders were similar in clinical characteristics at the outset. This study examines the relation between serum opsonic activity before initiation of granulocyte administration and clinical respons Opsonic activity to three test organisms (Escherichia coli 286 and ON 2, and Staphylococcus aureus) and to 15 blood stream isolates from 14 patients was measured as serum-dependent uptake of heat-killed 14C-labeled bacteria by normal donor leukopheresis granulocytes in an in vitro assay and compared with results obtained with a standard normal serum in each assay. At a concentration of 8 percent serum, all patient groups were equivalent to standard (90 to 102 percent) for the three test organisms. When rate-limiting concentrations of serum (1 to 2 percent) were employed, opsonic activity remained similar to standard for S. aureus in all patient groups and for the two E. coli strains in responders (82 to 98 percent). In contrast, opsonins for E. coli decreased to 41 to 50 percent of standard in nonresponders (p < 0.01). When patients with proved infection were separately analyzed, opsonin activity for E. coli 286 and ON 2 was significantly greater in responders than nonresponders (73.6 versus 34.9 percent and 124.8 versus 58.1 percent, respectively for the two strains) (p < 0.01). Patients with opsonin activity of 50 percent or greater of standard had a greater response rate (73 versus 19 percent and 45 versus 0 percent for the two E. coli strains) (p < 0.005 and p = 0.08, respectively). Eight of 10 patients with 75 percent or greater of standard for opsonic activity against their own blood stream isolates also responded, whereas zero of four with opsonins less than 75 percent of standard had a favorable out-come. These results indicate that serum opsonic activity may be a determinant of clinical response to granulocyte transfusion in infected granulocytopenic patients and may be predictive of outcome. We conclude that opsonic activity should be assessed in such patients before granulocyte administration and suggest a trial of plasma infusion in opsonin-deficient patients.