Thromb Haemost 2019; 119(06): 941-951
DOI: 10.1055/s-0039-1683913
Blood Cells, Inflammation and Infection
Georg Thieme Verlag KG Stuttgart · New York

Neutrophil and Monocyte Counts in Heparin-Induced Thrombocytopenia

Madeleine Hui
1  Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
,
Jo-Ann I. Sheppard
1  Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
,
Na Li
2  McMaster Centre for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
,
Theodore E. Warkentin
1  Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
2  McMaster Centre for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
3  Department of Medicine, McMaster University, Hamilton, Ontario, Canada
4  Hamilton Regional Laboratory Medicine Program, Hamilton General Hospital, Hamilton Health Sciences, Hamilton, Ontario, Canada
› Author Affiliations
Further Information

Publication History

15 October 2018

07 February 2019

Publication Date:
20 April 2019 (eFirst)

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Abstract

Background Heparin-induced thrombocytopenia (HIT) antibodies activate platelets, monocytes and neutrophils. Despite these findings, it is unknown whether white blood cell (WBC) counts, including neutrophils and monocytes, are altered during HIT.

Materials and Methods We evaluated changes in total WBC counts (including WBC subsets), in 50 post-cardiac surgery patients with serologically confirmed HIT (30 patients with HIT-associated thrombosis). Daily leukocyte counts were compared with those measured one day prior to HIT onset; WBC increases were classified as mild (20.0–49.9%), moderate (50.0–99.9%) or major (≥ 100% increase). We also compared changes in WBC counts in HIT patients with and without HIT-associated thrombosis, and non-HIT patients with thrombosis.

Results Most (34/50 [68.0%]) patients with HIT developed WBC count increases (mild, 35.3%; moderate, 44.1%; major, 20.6%). The peak WBC count occurred on day 4 (median) of HIT, which corresponded to day 10 (median) post-surgery. Absolute neutrophil counts increased in most patients (38/50 [76.0%]); whereas absolute monocyte counts rose in some patients, the overall tendency was for the monocyte count to decrease during HIT. Unexpectedly, we found that the increase in total WBC counts, as well as in neutrophils, was seen mainly in patients who developed HIT-associated or non-HIT-associated thrombosis; in contrast, no difference in monocyte levels was seen in patients with or without thrombosis.

Conclusion Leukocytosis and neutrophilia are commonly observed in patients with HIT, particularly in patients with HIT-associated thrombosis, as well as non-HIT patients with thrombosis. Thus, leukocytosis/neutrophilia should not infer automatically a diagnosis of infection or inflammation, when evaluating thrombocytopenia in heparin-exposed patients.

Keywords

heparin-induced thrombocytopenia - leukocytes - monocytes - neutrophils - thrombosis

Authors' Contributions

M.H. reviewed literature on WBC studies involving HIT, and collected WBC count data; T.E.W. designed the study and oversaw its conduct, collected and reviewed WBC count data, and wrote the first draft of the manuscript; J.I.S. performed data analyses and prepared the figures; N.L. performed statistical analyses; all authors reviewed and approved the final manuscript.