C3b Receptor‐Negative Peripheral Blood Neutrophils

Expression of peripheral blood neutrophil (PBN) C3b receptors, as assessed by rosette formation with C3b-coated ox erythrocytes, was examined and compared with neutrophil alkaline phosphatase (NAP) activities in both normal and haematologically abnormal conditions. The results indicate that a small percentage of normal PBN are apparently C3b receptor-negative and that these neutrophils do not appear to differ with respect to age from those with detectable C3b receptors. Examination of PBN C3b receptors from 154 cases of various haematological disorders revealed a significant proportion of cases with increased numbers of C3b receptor-negative neutrophils. These abnormalities did not appear to be related to peripheral leucocyte counts, NAP activities or serum lysozyme concentrations and it is suggested that the increased numbers of C3b receptor-negative PBN may be related to intravascular factors such as immune complexes.