Hemolytic capacity of human monocytes in normal subjects

The capacity of human monocytes to lyse human A1 erythrocytes in the presence of anti-A1 serum was determined in a group of normal subjects. It was found that monocyte hemolytic capacity varied widely, and that this variation was not accounted for by differences between the sexes or ages of the subjects. The intraassay variation was small compared with the variation observed between individual subjects and between assays of the same individual performed on different occasions. It is concluded that the variation observed is more likely to be due to differences in function of monocytes than to technical variation in assay performance. This variation limits the usefulness of the assay to those situations where there are large differences from control subjects or to studies where large numbers of patients are involved.