Gating of phagocytic leukocyte sub-populations during flow cytometric analyses. Gates were adjusted so that the percentage of cells analysed were identical to those identified using a Coulter® MicroDiff18 apparatus. Lymphocytes, red blood cells and debris were excluded from defined gates . Leukocyte subpopulations were selected by assignment of gates normally associated with (A) monocytes and (B) neutrophils . All flow cytometric analyses were performed using a Becton and Dickenson FACSCalibur flow cytometer.