In vitro neutrophil-erythrocyte rosette formation mediated by a serum factor (IgG).

In vitro neutrophil-erythrocyte rosette (NER) formation occurred in the peripheral blood of an elderly man. This caused problems in cross-matching for blood transfusion initially but was resolved by performing crossmatches at 37 degrees C because this phenomenon was temperature-dependent. NER formation was independent of complement and of the type of anticoagulant used. NERs were induced using normal control cells with the patient's plasma, serum, and the IgG fraction of serum. The rosetting factor was adsorbed by heterologous group-specific erythrocytes, but not by leukocytes. No neutrophil antibodies were identified.