Nucleated red blood cells for characterization of systemic inflammatory response syndrome in dogs.

Abstract

BACKGROUND: Nucleated red blood cells (nRBCs) are increased by disease processes and hematopoietic stress. OBJECTIVES: To evaluate the utility of nRBCs as a marker of disease severity and prognosis in dogs with systemic inflammatory response syndrome (SIRS). ANIMALS: Sixty-two client-owned dogs met the criteria of SIRS without anemia. METHODS: nRBC-positive (nRBCs: &#x2265;5/500, n&#x2009;=&#x2009;32) and nRBC-negative (nRBCs: <5/500, n&#x2009;=&#x2009;30) dogs were classified, and clinicopathological data, Acute Patient Physiologic and Laboratory Evaluation (APPLE) scores, cytokines, 2- and 4-weeks survival were compared. RESULTS: The median WBC (17.63, interquartile range [IQR]: 11.72-20.24&#x2009;&#xd7;&#x2009;10/L), neutrophils (12.28, IQR: 7.17-16.88&#x2009;&#xd7;&#x2009;10/L), band neutrophils (1288.5, IQR: 252.5-2575 cells/&#x3bc;L), serum IL-6 (731.80, IQR: 299.79-5522.05&#x2009;pg/mL), and plasma C-reactive protein (4.10, IQR: 1.00-8.58&#x2009;mg/L) were significantly higher in nRBC-positive dogs than negative dogs (11.27, IQR: 7.63-15.13&#x2009;&#xd7;&#x2009;10/L; 7.57, IQR: 4.96-11.71&#x2009;&#xd7;&#x2009;10/L; 62.5, IQR: 0-350.25 cells/&#x3bc;L; 232.30, IQR: 99.33-447.01&#x2009;pg/mL; 0.40, IQR: 0.10-3.00&#x2009;mg/L, respectively; P&#x2009;<&#x2009;.05). The median reticulocyte count (87.95, IQR: 52.45-130.55&#x2009;&#xd7;&#x2009;10/&#x3bc;L) and serum IL-3 (40.94, IQR: 29.85-53.52&#x2009;ng/L) were also significantly greater in nRBC-positive dogs than nRBC-negative dogs (46.00, IQR: 26.43-68.15&#x2009;&#xd7;&#x2009;10/&#x3bc;L; 25.24, IQR: 21.65-37.40&#x2009;ng/L, respectively; P&#x2009;<&#x2009;.01). The presence of circulating nRBCs, but not the reticulocyte count, at admission was predictive of death in dogs with SIRS at 2&#x2009;weeks (P&#x2009;=&#x2009;.01, AUC: 0.729) and 4&#x2009;weeks (P&#x2009;=&#x2009;.002, AUC: 0.731). The overall survival time was shorter in nRBC-positive dogs (95% CI, 47.35-113.90) than nRBC-negative dogs (95% CI, 90.92-135.55; P&#x2009;=&#x2009;.03). CONCLUSIONS AND CLINICAL IMPORTANCE: Measuring peripheral nRBCs in dogs with SIRS is rapid and clinically applicable, reflecting disease severity and associated prognosis.