Allergy, inflammation, hepatopathy and coagulation biomarkers in dogs with suspected anaphylaxis due to insect envenomation

Abstract

Objectives: To compare concentrations of biomarkers of; allergy [mast cell tryptase (MCT) and histamine], inflammation [interleukin (IL)-6,-10, and-18, CXCL8, CCL2, keratinocyte chemoattractant (KC), C-reactive protein (CRP)], endothelial glycocalyx shedding (hyaluronan), coagulation [prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and von Willebrand Factor antigen, protein C (PC) and antithrombin (AT) activity], and hepatopathy [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin] between dogs with anaphylaxis after suspected insect exposure, dogs with critical illness, and healthy dogs.

Design: This was a single center prospective clinical observational comparative biomarker study that included 25 dogs with anaphylaxis (evidence of insect exposure, acute dermatological signs, and other organ involvement), 30 dogs with other critical illness, and 20 healthy dogs. Differences across groups in biomarker concentrations were tested using one-way ANOVA or Kruskal-Wallis test, with significant P values (<0.05) reported for pairwise differences detected by post-hoc tests. Logistic regression models were used to calculate the area under the receiver operator characteristic curve (AUROC) for discrimination between anaphylaxis and non-anaphylactic illness.

Results: Histamine concentration was significantly higher in the anaphylaxis group than the healthy (P < 0.001) and critically ill groups (P < 0.001), whereas no differences in MCT were detected amongst groups. Biomarker concentrations that were increased relative to healthy dogs in both the anaphylaxis and critically ill groups included IL-10 (P < 0.001 and P = 0.007, respectively), CCL2 (P = 0.007 and P < 0.001, respectively) and AST (both P < 0.001), whereas only the critically ill group had significantly increased CRP (P < 0.001), IL-6 (P < 0.001), KC (P < 0.001), ALP (P < 0.001), and fibrinogen (P = 0.016) concentrations, compared to the healthy group. Only dogs with anaphylaxis had significantly higher hyaluronan (P = 0.021) and ALT (P = 0.021) concentrations, and lower PC (P = 0.030) and AT (P = 0.032) activities, compared to healthy dogs. Both CRP and histamine concentration showed good discrimination between anaphylaxis and other critical illness, with an AUROC of 0.96 (95% CI 0.91-1) and 0.81 (95% CI 0.69-0.93), respectively.

Conclusions: This preliminary study in dogs with anaphylaxis after suspected insect exposure, found evidence of an early innate immune response, glycocalyx shedding and anticoagulant consumption. Both CRP and histamine showed potential clinical utility for differentiation between anaphylaxis and other critical illness.

Keywords: C-reactive protein; antithrombin (AT); canine anaphylaxis; cytokines; histamine; hyaluronan; mast cell tryptase; protein C (PC).

Figure 1

Inclusion criteria for dogs with anaphylaxis due to suspected insect exposure.

Figure 2

Scatter and box-and-whisker plots of serum histamine and plasma mast cell tryptase (MCT) concentrations in dogs with anaphylaxis, dogs with other critical illness and healthy dogs. The box-and-whisker plots display either mean and 95% confidence interval (MCT) or geometric mean and 95% confidence interval (histamine) as appropriate for the data distribution. * and **indicate a significant (P < 0.05) difference between groups.

Figure 3

Scatter and box-and-whisker plots of C reactive protein (CRP), interleukin (IL) 6 and 10, C-C motif chemokine ligand-2 (CCL2), keratinocyte-derived chemokine (KC) and hyaluronan concentrations in dogs with anaphylaxis, dogs with other critical illness and healthy dogs. The box-and-whisker plots display either geometric mean and 95% confidence interval (CRP, KC and hyaluronan) or median and Q1, Q3 (IL6, IL10 and CCL2) as appropriate for the data distribution. * and **indicate a significant (P < 0.05) difference between groups.

Figure 4

Scatter and box-and-whisker plots of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) concentrations in dogs with anaphylaxis, dogs with other critical illness and healthy dogs. The box-and-whisker plots display either geometric mean and 95% confidence interval (ALP) or median and Q1, Q3 (ALT and AST) as appropriate for the data distribution. * and **indicate a significant (P < 0.05) difference between groups.

Figure 5

Scatter and box-and-whisker plots of fibrinogen concentration, protein C and, antithrombin activity in dogs with anaphylaxis, dogs with other critical illness and healthy dogs. The box-and-whisker plots display either mean and 95% confidence interval (protein C and antithrombin) or median and Q1, Q3 (fibrinogen) as indicated by the individual Y axis as appropriate for the data distribution. * and **indicate a significant (P < 0.05) difference between groups.