Affiliations: School of Molecular and Medical Biosciences, University of Wales, P.O. Box 911, Cardiff, CF1 3US, UK | Department of Vascular Surgery, University of Wales College of Medicine, Heath Park, Cardiff, CF4 4XW, UK
Note: [] Reprint requests to: Dr S.‐A. Evans, School of Molecular and Medical Biosciences, University of Wales, P.O. Box 911, Cardiff, UK. Tel.: 1222 874118; Fax: 1222 875176; E‐mail: evanssa1@ cf.ac.uk.
Abstract: Leukocytes are characterised from their influence on the filterability of undiluted blood from patients with PAOD (intermittent claudicants – Fontaine Stage II) and a group of sex and age‐matched controls. Undiluted blood was filtered through 5 \mum Nuclepore (Hemafil) filters for 300 s, at 711 Pa and room temperature, using a custom‐made constant pressure filtrometer. Four populations of leukocytes are identified in both groups. In the control group, 94.4% of the leukocytes are identified as fast leukocytes with a transit time of 1.8 s. The remaining white cells are recognised as slow flowing leukocytes and subdivided into three further sub‐populations. The first of these (SL_1; 2.8% of total leukocyte count) is characterised by a transit time of 31.7 s, a second population (SL_2; 1.5% of total leukocyte count) by a transit time of 145.8 s while the remaining cells are identified as pore blockers (PB) under these conditions. A similar rheological classification is valid in the patients but the sum of the three minor populations is elevated compared to controls (p= 0.001) although there is no overall leukocytosis. The only significant difference in flow properties of any blood cells, between the two groups of volunteers, is seen in the major population of leukocytes with an elevated transit time of 2.4 s. Stepwise regression analysis identifies the concentration of fast leukocytes, SL_2 and PB as the major variables affecting blood flow through the filter. It is argued that the higher concentration of SL_{2} and PB probably reflect the increased sensitivity of neutrophils to physical stimuli.
