Studies of the plasma factor which induces augmented granulocyte adherence during hemodialysis

Transient granulocytopenia develops during the first few minutes of hemodialysis, and is associated with a marked increase in granulocyte adherence as the cells marginate in the pulmonary circulation. The increased adherence is mediated by factors present in the plasma, thought to be complement components activated by the dialysis coil. In the present study, an assay of plasma for adherence-augmenting activity shows that it is maximal at 15 min after starting dialysis, and undetectable at 40 min. The factor is not affected by heating to 56 degrees C for 30 min, or by incubation at 37 degrees C for 7 days, nor does dialysis for 24 h against physiologic saline diminish its activity. However, exposure to pH 6.0 reduces the activity to 58.4% of control, and pH 5.0 reduces it to 40.1%. Finally, pretreatment of patients with prednisone before hemodialysis does not prevent granulocytopenia or increased adherence. These findings are discussed in relation to the known properties of various biologically active fragments of complement.