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Equine blood reticulocytes: reference intervals, physiological and pathological changes

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Abstract

High-sensitivity haematology analysers detect equine blood reticulocytes, but their analysis and quantitation is largely unstudied. We assessed whether equine reticulocytes are affected by pathological or physiological factors, determined reference intervals, and examined reticulocyte and related, erythron parameters using 6-years’ data (Advia 2120) from our hospital archives. Data was categorised according to horse age (foals < 12 months), breed (hot-, warm-, cold-blooded), presence of anaemia and various diseases. In adults, reticulocytes (× 109/L) were 20% lower in cold-blooded horses compared to others (4.14 ± 2.3, 25 vs 5.15 ± 3.3, 157; data shown as mean ± SD, n; p < 0.05.) There was no gender effect. In thoroughbreds, foals had 50% higher reticulocytes than adults (7.5 ± 4.5, 18 vs 5.0 ± 3.5, 56). We determined the first reference interval for healthy adult horses as 5.0 ± 3.2,182, 1.16–13.1. Reticulocyte counts were 120% higher with marked anaemia (11.0 ± 9.4, 6) but 36% with other diseases (6.9 ± 4.2, 74), versus reference mean. Erythrocyte size (MCV)/reticulocyte haemoglobin content (CHr) were 21/14% lower in foals versus adults and 12/37% higher with marked anaemia. Immature reticulocytes (IRF-H) were 60% lower in foals versus adult thoroughbreds, and 87% with marked anaemia. In conclusion, equine reticulocytes are only mildly increased by physiological parameters (breed, age, but not gender), various non-blood diseases (colic, dysproteinaemia) and marked anaemia. Reticulocyte counts are substantially lower in horses versus other species; their clinical use is limited to marked anaemias. This is consistent with the greater erythrocyte storage and buffering capacity of the spleen of the horse. Finally, this study supports the theory of a reticulocyte maturation role for equine spleen.

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References

  • Axon JE, Palmer JE (2008) Clinical pathology of the foal. Vet Clin North Am Equine Pract 24(2):357–385. https://doi.org/10.1016/j.cveq.2008.03.005

    Article  PubMed  Google Scholar 

  • Bauer N, Nakagawa J, Dunker C, Failing K, Moritz A (2012) Evaluation of the automated haematology analyser Sysmex XT-2000iV™ compared to the ADVIA ® 2120 for its use in dogs, cats, and horses. Part II: accuracy of leukocyte differential and reticulocyte count, impact of anticoagulant and sample aging. J Vet Diagn Investig 24(1):74–89. https://doi.org/10.1177/1040638711436243

    Article  Google Scholar 

  • Brace RA, Langendörfer C, Song TB, Mock DM (2000) Red blood cell life span in the ovine fetus. Am J Physiol Regul Integr Comp Physiol 279(4):R1196–R1204

    Article  CAS  PubMed  Google Scholar 

  • Brugnara C, Laufer MR, Friedman AJ, Bridges K, Platt O (1994) Reticulocyte hemoglobin content (CHr): early indicator of iron deficiency and response to therapy. Blood 83(10):3100–3101

    CAS  PubMed  Google Scholar 

  • Buttarello M, Plebani M (2008) Automated blood cell counts: state of the art. Am J Clin Pathol 130(1):104–116. https://doi.org/10.1309/EK3C7CTDKNVPXVTN

    Article  PubMed  Google Scholar 

  • Chang CC, Kass L (1997) Clinical significance of immature reticulocyte fraction determined by automated reticulocyte counting. Am J Clin Pathol 108(1):69–73

    Article  CAS  PubMed  Google Scholar 

  • Christensen RD, Henry E, Bennett ST, Yaish HM (2016) Reference intervals for reticulocyte parameters of infants during their first 90 days after birth. J Perinatol 36(1):61–66. https://doi.org/10.1038/jp.2015.140

    Article  CAS  PubMed  Google Scholar 

  • Clark P, Mogg TD, Tvedten HW, Korcal D (2002) Artifactual changes in equine blood following storage, detected using the Advia 120 hematology analyzer. Vet Clin Pathol 31(2):90–94

    Article  PubMed  Google Scholar 

  • Cooper C, Sears W, Bienzle D (2005) Reticulocyte changes after experimental anemia and erythropoietin treatment of horses. J Appl Physiol 99(3):915–921. https://doi.org/10.1152/japplphysiol.00438.2005

    Article  CAS  PubMed  Google Scholar 

  • Cowgill ES, Neel JA, Grindem CB (2003) Clinical application of reticulocytes counts in dogs and cats. Vet Clin Small Anim 33:1223–1244

    Article  Google Scholar 

  • Friedrichs KR, Harr KE, Freeman KP, Szladovits B, Walton RM, Barnhart KF, Blanco-Chavez J (2012) ASVCP reference interval guidelines: determination of de novo reference intervals in veterinary species and other related topics. Vet Clin Pathol 41(4):441–453. https://doi.org/10.1111/vcp.12006

    Article  PubMed  Google Scholar 

  • Giordano A, Rossi G, Pieralisi C, Paltrinieri S (2008) Evaluation of equine hemograms using the ADVIA 120 as compared with an impedance counter and manual differential count. Vet Clin Pathol 37(1):21–30. https://doi.org/10.1111/j.1939-165X.2008.00012.x

    Article  PubMed  Google Scholar 

  • Grondin TM, Dewitt SF (2010) Normal hematology of the horse and donkey. In: Weiss DJ, Wardrop KJ (eds) Schalm's veterinary hematology, 6th edn. Blackwell, Iowa, pp 821–828

    Google Scholar 

  • Harvey JW (1990) Normal hematologic values. In: Koterba AM, Drummond WH, Kosch PC (eds) Equine Clinical Neonatology. Lea & Febiger, Philadelphia, pp 561–570

    Google Scholar 

  • Jain NC (1993) Essentials of veterinary hematology. Lea and Febiger, Philadelphia, p 417

  • Jelkmann W (2007) Erythropoietin after a century of research: younger than ever. Eur J Haematol 78:183–205

    Article  CAS  PubMed  Google Scholar 

  • Kline H, Foreman JH (1991) Heart and spleen weights as a function of breed and somatotype. Equine Exercise Physiology 3, pp 17–21

  • Lilliehook I, Tvedten H (2009) Validation of the Sysmex XT-2000iV hematology system for dogs, cats, and horses. II. Differential leukocyte counts. Vet Clin Pathol 38:175–182

    Article  PubMed  Google Scholar 

  • Lorber M (1958) The effects of splenectomy on the red blood cells of the dog with particular emphasis on the reticulocyte response. Blood 13:972–985

    CAS  PubMed  Google Scholar 

  • Lording PM (2008) Erythrocytes. Vet Clin North Am Equine Pract 24(2):225–237. https://doi.org/10.1016/j.cveq.2008.04.002

    Article  PubMed  Google Scholar 

  • Lumsden HJ, Valli VE, McSherry BJ, Robinson GA, Claxton MJ (1975) The kinetics of hematopoiesis in the light horse III. The hematological response to hemolytic anemia. Can J Comp Med 39(3):332–339

    CAS  PubMed  PubMed Central  Google Scholar 

  • Lumsden JH, Rowe R, Mullen K (1980) Hematology and biochemistry reference values for the light horse. Can J Comp Med 44(1):32–42

    CAS  PubMed  PubMed Central  Google Scholar 

  • McGowan C (2008) Clinical pathology in the racing horse: the role of clinical pathology in assessing fitness and performance in the racehorse. Vet Clin North Am Equine Pract 24(2):405–421. https://doi.org/10.1016/j.cveq.2008.03.001

    Article  PubMed  Google Scholar 

  • O’Brien PJ (2017) Report and abstracts for 17th Spring ACCP conference with training workshops, and technology exhibits. 26:1–7

  • O’Brien PJ, Rooney MT, Reik TR, Thatte HS, Rempel WE, Addis PB, Louis CF (1995) Porcine malignant hyperthermia susceptibility: erythrocytic osmotic fragility. Am J Vet Res 46(7):1451–1456

    Google Scholar 

  • Olver CH (2010) Erythropoiesis. In: Weiss DJ, Wardrop KJ (eds) Schalm’s veterinary hematology, 6th edn. Blackwell, Iowa, pp 36–42

    Google Scholar 

  • Pattullo KM, Kidney BA, Taylor SM, Jackson ML (2015) Reticulocytosis in nonanemic dogs: increasing prevalence and potential etiologies. Vet Clin Pathol 44(1):26–36. https://doi.org/10.1111/vcp.12215

    Article  PubMed  Google Scholar 

  • Pearson HA (1967) Life-span of the fetal red blood cell. J Pediatr 70(2):166–171

    Article  CAS  PubMed  Google Scholar 

  • Piccione G, Casella S, Giannetto G, Messina V, Monteverde V, Caola G, Guttadauro S (2010) Haematological and haematochemical responses to training and competition in standardbred horses. Comp Clin Pathol 19(1):95–101

    Article  Google Scholar 

  • Radin MJ, Eubank MC, Weiser MG (1986) Electronic measurement of erythrocyte volume and volume heterogeneity in horses during erythrocyte regeneration associated with experimental anemias. Vet Pathol 23(6):656–660. https://doi.org/10.1177/030098588602300602

    Article  CAS  PubMed  Google Scholar 

  • Rhodes MM et al (2016) Stress reticulocytes lose transferrin receptors by an extrinsic process involving spleen and macrophages. Am J Hematol 91(9):875–882

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Rizzi TE, Meinkoth JH, Clinkenbeard KD (2010) Normal hematology of the dog. In: Weiss DJ, Wardrop KJ (eds) Schalm's veterinary hematology, 6th edn. Blackwell, Iowa, pp 799–810

    Google Scholar 

  • Rout ED, Webb TL, Laurence HM, Long L, Olver CS (2015) Transferrin receptor expression in serum exosomes as a marker of regenerative anaemia in the horse. Equine Vet J 47(1):101–106. https://doi.org/10.1111/evj.12235

    Article  CAS  PubMed  Google Scholar 

  • Satue K, Hernandez A, Munoz A (2012) Physiological factors in the interpretation of equine hematological profile. In: Lawrie C (ed) Hematology—Science and Practice. InTech. https://doi.org/10.5772/38961

  • Satue K, Munoz A, Gardon JC (2014) Interpretation of alterations in the horse erythrogram. J Hematol Res 1:1–10. https://doi.org/10.12974/2312-5411.2014.01.01.1

    Article  Google Scholar 

  • Song SH, Groom AC (1972) Sequestration and possible maturation of reticulocytes in the normal spleen. Can J Physiol Pharmacol 50(5):400–406

    Article  CAS  PubMed  Google Scholar 

  • Steinberg JD, Olver CS (2005) Hematologic and biochemical abnormalities indicating iron deficiency are associated with decreased reticulocyte hemoglobin content (CHr) and reticulocyte volume (rMCV) in dogs. Vet Clin Pathol 34(1):23–27

    Article  PubMed  Google Scholar 

  • Walton RM (2013) Equine clinical pathology. Blackwell, Iowa

    Book  Google Scholar 

  • Weiser G, Kohn C, Vachon A (1983) Erythrocyte volume distribution analysis and hematologic changes in two horses with immune-mediated hemolytic anemia. Vet Pathol 20(4):424–433. https://doi.org/10.1177/030098588302000405

    Article  CAS  PubMed  Google Scholar 

  • Weiss DJ, Moritz A (2003) Equine immune-mediated hemolytic anemia associated with Clostridium perfringens infection. Vet Clin Pathol 32(1):22–26

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

The authors wish to thank the staff of the clinical pathology laboratory. We also thank Prof Kurt Zimmerman, Virginia-Maryland College of Veterinary Medicine, for his thorough review of the manuscript and helpful comments.

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  1. Clinical Pathology Laboratory, School of Veterinary Medicine, Veterinary Sciences Centre, University College Dublin, Room 013, Belfield, D4, Ireland

    M. Balan, M. McCullough & Peter J. O’Brien

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  1. M. Balan
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  2. M. McCullough
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  3. Peter J. O’Brien
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Correspondence to Peter J. O’Brien.

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A preliminary report of these findings has been made at the 17th Annual conference of the Association for Comparative Clinical Pathology, Mar 12-13, 2016 (O’Brien 2017)

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Balan, M., McCullough, M. & O’Brien, P.J. Equine blood reticulocytes: reference intervals, physiological and pathological changes. Comp Clin Pathol 28, 53–62 (2019). https://doi.org/10.1007/s00580-018-2820-4

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