Lack of Evidence of Pregnancy-Induced Alloantibodies in Dogs

Background: It is controversial whether or not pregnant bitches become sensitized to red blood cell (RBC) antigens.
Hypothesis: Bitches do not develop alloantibodies to RBC antigens during gestation and can be used safely as blood donors.
Animals: The study group included 35 healthy female dogs with a prior history of 1 (n = 12), 2 (n = 14), or ≥ 3 (n = 9) pregnancies. The control group consisted of 15 healthy female dogs without any history of pregnancy.
Methods: All dogs were blood typed for dog erythrocyte antigens (DEA) 1.1, 1.2, 3, 4, 5, and 7 using ethylenediaminetetraacetic acid blood samples and polyclonal antisera. Antibody screening was performed with serum and canine RBC panels of known blood type. An autocontrol and direct antiglobulin test were performed to rule out the presence of autoantibodies.
Results: The only alloantibodies identified were those against DEA 7 and the prevalence of anti-DEA 7 alloantibodies was similar in dogs with known history of pregnancy (11.4%) and in the control group (13.3%).
Conclusions and Clinical Importance: These results confirm previous studies and clinical transfusion medicine experience. Naturally occurring anti-DEA 7 alloantibodies have been reported but their clinical relevance has not been shown. Pregnancy does not appear to sensitize dogs to RBC antigens. Consequently, dogs with prior history of pregnancy can be used safely as blood donors. Conversely, no additional pretransfusion compatibility studies would be required should these dogs themselves need to be transfused.     

Survival Time of Cross‐Match Incompatible Red Blood Cells in Adult Horses

Background

There is a markedly reduced half‐life of transfused RBCs when donor and recipient cats or humans are cross‐match incompatible. Only 10–20% of horses have naturally occurring alloantibodies. Therefore, cross‐match testing before blood transfusion is not always performed.

Hypothesis

Cross‐match incompatibility predicts shortened RBC survival time as compared to that of compatible or autologous blood.

Animals

Twenty healthy adult horses.

Methods

Prospective trial. Blood type, anti‐RBC antibody screen (before and 1 month after transfusion) and major and minor cross‐match determined 10 donor‐recipient pairs. Two pairs were cross‐match compatible, the remainder incompatible. Donor blood (4 L) was collected into citrate phosphate dextrose adenine‐1, labeled with NHS‐biotin, and transfused into recipients. Samples were collected at 1 hour and 1, 2, 3, 5, 7, 14, 21, 28, and 35 days after transfusion, and biotinylated RBCs were detected by flow cytometry. Horses were monitored for transfusion reaction during transfusion and daily for 5 days.

Results

Cross‐match incompatibility was significantly associated with decreased RBC survival time (P < .001). The half‐life of transfused incompatible (cross‐match >1+) allogenic equine RBCs was 4.7 (95% CI, 3.2–6.2) days versus 33.5 (24–43) days for compatible pairings. Cross‐match incompatibility was associated with acute febrile transfusion reaction (P = .0083). At day 30, only 1 horse had developed novel anti‐RBC antibodies.

Conclusions and Clinical Importance

Cross‐match incompatibility was predictive of febrile transfusion reaction and shortened transfused RBC survival, but did not result in production of anti‐RBC antibodies at 30 days. Cross‐match testing before transfusion is recommended.     

Glutathione Peroxidase Activity,Plasma Total Antioxidant Capacity,and Urinary F2‐ Isoprostanes as Markers of Oxidative Stress in Anemic Dogs

Background

Oxidative stress plays a role in the pathophysiology of several diseases and has been documented as a contributor to disease in both the human and veterinary literature. One at‐risk cell is the erythrocyte, however, the role of oxidative stress in anemia in dogs has not been widely investigated.

Hypothesis/Objective

Anemic dogs will have an alteration in the activity of glutathione peroxidase (GPx), a decrease in of total antioxidant capacity (TAC), and an increased concentration of urinary 15‐F₂‐isoprostanes (F₂‐IsoP) when compared to healthy dogs.

Animals

40 client‐owned dogs with anemia (PCV <30%) age‐matched to 40 client‐owned healthy control dogs.

Methods

Prospective, cross‐sectional study. Whole blood GPx activity, plasma TAC, and urinary F₂‐isoprostane concentrations were evaluated in each dog and compared between groups.

Results

Anemic dogs had significantly lower GPx activity (43.1 × 10³ +/‐ 1.6 × 10³ U/L) than did dogs in the control group (75.8 × 10³ +/‐ 2.0 × 10³ U/L; P < 0.0001). The GPx activity in dogs with hemolysis (10³ +/‐ 0.8 × 10³ U/L) was not significantly different (P = 0.57) than in dogs with nonhemolytic anemia (43.5 × 10³ +/‐ 1.1 × 10³ U/L). The TAC concentrations (P = 0.15) and urinary F₂‐isoprostanes (P = 0.73) did not significantly differ between groups.

Conclusions and Clinical Importance

Glutathione peroxidase activity was significantly decreased in anemic dogs indicating oxidative stress. Additional studies are warranted to determine if antioxidant supplementation would improve survival and overall outcome as part of a therapeutic regimen for anemic dogs.     

Relationship of Plasma N‐terminal Pro‐brain Natriuretic Peptide Concentrations to Heart Failure Classification and Cause of Respiratory Distress in Dogs Using a 2nd Generation ELISA Assay

Background

Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD).

Hypothesis/Objectives

Determine the utility of plasma N‐terminal pro‐brain natriuretic peptide concentration [NT‐proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity.

Animals

Client‐owned dogs (n = 291).

Methods

Multicenter, cross‐sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM‐HD) schemes without knowledge of [NT‐proBNP] results. Receiver‐operating characteristic curve analysis assessed the capacity of [NT‐proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT‐proBNP] and HD severity.

Results

Plasma [NT‐proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769–8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672–2,704 pmol/L; P < .0001). A cut‐off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end‐systole, and ACVIM‐HD scheme most accurately associated average plasma [NT‐proBNP] with HD severity.

Conclusions and Clinical Importance

Plasma [NT‐proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT‐BNP] increased significantly as a function of HD severity using the ACVIM‐HD classification scheme.     

Pathogenesis and Subsequent Cross‐Protection of Influenza Virus Infection in Pigs Sustained by an H1N2 Strain

The H1N1, H3N2 and, more recently, H1N2 subtypes of influenza A virus are presently co‐circulating in swine herds in several countries. The objectives of this study were to investigate the pathogenesis of Sw/Italy/1521/98 (H1N2) influenza virus, isolated from respiratory tissues of pigs from herds in Northern Italy, and to evaluate its potential cross‐protection against the Sw/Fin/2899/82 (H1N1) strain. In the pathogenesis test, eight pigs were intranasally infected with H1N2 virus; at pre‐determined intervals, these animals were killed and necropsied, along with eight uninfected animals. In the cross‐protection test, sixteen pigs were infected by intranasal (i.n.) and intratracheal (i.t.) routes with either H1N2 or H1N1 virus. Twenty days later, all pigs were challenged (by the same route), with either the homologous H1N2 or heterologous H1N1 virus strains. Control group was inoculated with culture medium alone. On post‐challenge days (PCD) 1 and 3, two pigs from each infected group, along with one control pig, were killed. Clinical, virological, serological and histopathological investigations were performed in both the pathogenicity and cross‐protection tests. In the pathogenicity test, mild clinical signs were observed in two pigs during 3 and 4 days, respectively. Virus was isolated from two pigs over 6 days and from lung samples of pigs killed on post‐infection days 2 and 4. Seroconversion was detected in the two infected animals killed 15 days after infection. In the cross‐protection study, mild clinical respiratory signs were detected in all pigs infected with either the H1N2 or H1N1 virus. The virus was isolated from nasal swabs of almost all pigs till 6 days. After the challenge infection, the pigs remained clinically healthy and virus isolation from the nasal secretions or lung samples was sporadic. Antibody titres in H1N1 or H1N2 infected groups were similar, whereas the H1N2 sub‐type induced less protection against re‐infection by homologous and heterologous virus than H1N1 sub‐type. The controls had no signs of the disease. In the H1N2 infected pigs, a reduced number of goblet cells in nasal and tracheal mucosa and small foci of lymphomononuclear cell infiltrates in the submucosa were detected. Furthermore, the goblet cell reduction was related to the time of infection. Diffuse mild interstitial pneumonia was also recorded in pigs infected with the H1N2 virus and challenged with either H1N1or H1N2 pigs. These studies showed the moderate virulence of the H1N2 virus and a partial cross‐protection against heterologous infection.