Clinical significance of blood cell ratios in healthy and sick Leishmania infantum-seropositive dogs

Parasit Vectors. 2024 Oct 23;17(1):435. doi: 10.1186/s13071-024-06522-z.

Abstract

Background: The accuracy of blood cell ratios (BCRs) as cost-effective and easily accessible diagnostic and prognostic markers of inflammatory conditions has been investigated in veterinary medicine in recent years.

Methods: Neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), and platelet-to-lymphocyte (PLR) ratios were studied in 195 dogs clinically evaluated and tested for anti-Leishmania infantum (Li) antibodies (Li-seronegative (Li-), n = 10; Li-seropositive clinically healthy (Li+healthy), n = 100; Li-seropositive with clinical and/or clinicopathological abnormalities (Li+sick), n = 85). The Li+sick dogs were classified in LeishVet stages IIa/IIb (Li+IIa/IIb) (n = 66) and III/IV (Li+III/IV) (n = 19). BCR relationships with LeishVet clinical stage, antibody levels, and serum protein electrophoretic fraction concentrations were investigated.

Results: Higher NLR values were found in Li+, Li+healthy, and Li+IIa/IIb sick dogs compared to Li- dogs (P < 0.001). Higher NLR and MLR were found in Li+sick (NLR, P < 0.001; MLR, P = 0.034) and Li+III/IV dogs (NLR, P < 0.001; MLR, P = 0.005) compared to Li- dogs, and in Li+III/IV dogs (NLR, P = 0.002; MLR, P < 0.001) compared to Li+healthy. All three BCRs were higher in Li+sick (NLR, MLR, P < 0.001; PLR, P = 0.023) and Li+IIa/IIb dogs (NLR P < 0.001; MLR P = 0.001; PLR, P = 0.012) compared to Li+healthy dogs. The BCRs failed to distinguish dogs with moderate (Li+IIa/IIb) and severe or very severe disease (Li+III/IV). BCRs demonstrated weak positive correlations with serum globulin fractions and antibody levels, and weak negative correlations with serum albumin level were found. Li+sick dogs presenting hypoalbuminemia showed higher MLR ratios (P = 0.001) than those with normal albumin values.

Conclusions: This study shows that BCR measures provide useful information for differentiating antibody-positive healthy and sick dogs at diagnosis. Dogs with hypoalbuminemia showed higher MLR values despite monocytosis being very rare.

Keywords: Canine leishmaniosis; Clinical staging and LeishVet; Monocyte-to-lymphocyte ratio; Neutrophil-to-lymphocyte ratio; Platelet-to-lymphocyte ratio; Serum protein electrophoresis.

MeSH terms

  • Animals
  • Antibodies, Protozoan* / blood
  • Blood Cell Count / veterinary
  • Blood Platelets / immunology
  • Blood Platelets / parasitology
  • Clinical Relevance
  • Dog Diseases* / blood
  • Dog Diseases* / immunology
  • Dog Diseases* / parasitology
  • Dogs
  • Female
  • Leishmania infantum* / immunology
  • Leishmaniasis, Visceral* / blood
  • Leishmaniasis, Visceral* / diagnosis
  • Leishmaniasis, Visceral* / immunology
  • Leishmaniasis, Visceral* / parasitology
  • Leishmaniasis, Visceral* / veterinary
  • Lymphocytes / immunology
  • Male
  • Monocytes / immunology
  • Neutrophils / immunology

Substances

  • Antibodies, Protozoan