Lap. Ballering et al., Lymphocyte-neutrophilic granulocyte aggregates with and without associatedspurious leukopenia in Beagle dogs, COMP HAEMAT, 10(2), 2000, pp. 105-111
Three cases are reported of male Beagle dogs which initially showed indicat
ions for clumped cells on the scattergrams of a haematology analyser with a
utomated '5-part' white blood cell, WBC, differentiation using potassium ED
TA anticoagulated blood. On analysis of the bloodsmears leucocyte aggregate
s were observed consisting of lymphocytes and neutrophilic granulocytes in
ratios varying from 1:1.1 to 1.1.9. The aggregates differed in size from 5
to 10 cells. In aggregates, occasionally eosinophilic granulocytes were pre
sent but no thrombocytes. In two cases thrombocyte aggregates with leucocyt
es on the surface ('inverted' rosettes) were observed with sodium citrate a
nd lithium heparin anticoagulated blood samples.
In one case the leucocyte agglutination seems to be of spontaneous origin b
ecause the aggregates were present in the predosing analysis and after plac
ebo treatment. In the other two cases the aggregates arose during the treat
ment with an experimental medicine. In two cases spurious leukopenia was ob
served associated with the leucocyte aggregates but in the other case the q
uantity and distribution over the various classes of white blood cells appe
ared unchanged.
Methodology experiments indicated that the formation of the aggregates were
temperature- and EDTA-dependent effects on the leucocyte membrane factors,
possibly aided by serum globulins.