Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Acta Haematol 2007;118:73–76 DOI: 10.1159/000103216 Sustained Leukocyte Count during Rising Cortisol Level Varda Deutsch a Liat Lerner-Geva d, e Adi Reches b Valentina Boyko d Rona Limor c Dan Grisaru b, e Departments of a Hematology and b Obstetrics and Gynecology, c Endocrinology Laboratory, Tel Aviv Sourasky Medical Center, d Women and Children’s Health Research Unit, Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer and e Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Introduction Leukocytes play a pivotal role in the defense against infections, especially bacterial infections. Blood leuko- cytes constitute two interchangeable subpopulations, the marginated and the circulating pools. These two sub- compartments are found in normal conditions and are potentially affected by abnormal situations, either patho- logical or physiological. Under normal conditions, about half of the leukocyte population circulates in the periph- eral blood, maintaining a dynamic equilibrium with the tissue or marginated leukocytes. The latter are found in the lungs, liver, spleen and bone marrow, adherent to or at least in contact with the endothelium of small blood vessels. Hematogenic signals of infection or acute inflam- mation, such as adrenaline, catecholamine or cortisol, ac- tivate mature granulocytes in the bone marrow and tis- sues to undergo rapid demargination, causing increases in the circulating pool of leukocytes in the blood [1–3]. Increased demands for circulating white blood cells (WBCs) arise in both pathological and nonpathological situations (e.g., during exercise) [4], following burns [5], infectious diseases and inflammatory processes [6] . Ad- ditionally, a large reserve of mature and immature bone marrow leukocytes can be mobilized over several days to the circulation following cytokine stimulation. While we do not yet have a thorough understanding of the mecha- Key Words Cortisol levels, increased  Leukocytosis  Platelet levels Abstract Aims: To follow the trend of leukocyte counts relative to the serum cortisol levels in hospitalized patients. Methods: We retrospectively reviewed the charts of 59 hospitalized pa- tients who had sequential blood profiles during a 2-week period. Results: The study cohort was divided into two sub- groups according to the categorical cortisol levels: those within the normal range ( ! 25  g/dl; n = 31 patients) and those above the normal range ( 6 25  g/dl; n = 28 patients). The baseline white blood cell counts (WBCCs) were similar in both groups. After 1 week, however, the WBCCs dropped significantly in the presence of normal cortisol levels and in- creased in the presence of elevated cortisol levels (p = 0.002). This pattern was not followed by the platelet counts. A sig- nificant correlation was observed between the cortisol lev- els and the 1 week concomitant WBCC (r = 0.33). Conclusion: Cortisol may be the mechanism with a positive effect on the maintenance of elevated leukocyte counts. Copyright © 2007 S. Karger AG, Basel Received: November 20, 2006 Accepted after revision: March 15, 2007 Published online: May 29, 2007 Dan Grisaru, MD, PhD Gynecologic Oncology Service, Tel Aviv Sourasky Medical Center 6 Weizman Street 64239 Tel Aviv (Israel) Tel. +972 3692 5622, Fax +972 3692 5670, E-Mail grisaro@post.tau.ac.il © 2007 S. Karger AG, Basel 0001–5792/07/1182–0073$23.50/0 Accessible online at: www.karger.com/aha Dr. Deutsch and Dr. Lerner-Geva contributed equally to this paper.