An Evaluation of Hemostatic Dysregulation in Canine Multicentric Lymphoma

Multiple hemostatic abnormalities are associated with paraneoplastic syndrome and some malignant tumors. Lymphoma is the most common hematopoietic neoplasm in dogs, sometimes associated with hemostatic changes. The objectives of this study were to evaluate the behavior of coagulation parameters in dogs with multicentric lymphoma compared with diseased dogs without lymphoma, to separately evaluate the effect of immunophenotype (B lymphoma versus T lymphoma) on the variables of interest as well as the effect of disease stage (stage II to IV versus stage V). Specifically, a cross-sectional study was performed with a matched comparison group considering 170 dogs with B or T lymphoma (group 1) and 170 dogs with no lymphoma or other neoplastic processes but other diseases (group 0). Eight coagulation parameters were evaluated: platelet count (Plt), activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), fibrinogen, fibrin/products of fibrinogen degradation (FDPs), fibrin D-dimers, and antithrombin (AT). Dogs with lymphoma showed prolonged PT and TT, decreased fibrinogen, increased FDP, and decreased Plt compared with group 0. The effect of disease stage was evaluated separately for dogs with stage II to IV lymphoma and dogs with stage V lymphoma; patients with stage II-IV lymphoma showed no significant differences, while in dogs with stage V lymphoma, a prolongation of PT and TT, a decrease in fibrinogen, an increase in FDPs and a decrease in Plt were found compared with the group 0. Finally, the comparison between B lymphoma and T lymphoma showed no significant differences in coagulation parameters between the two groups. Logistic regression analysis demonstrated that low fibrinogen and platelet levels were the most significant predictors of lymphoma in a cohort of canine patients. These hemostatic abnormalities in lymphoma appeared to be associated with the stage of the disease rather than the lymphoma immunophenotype. These findings pave the way for the possible scenario of lymphoma-associated fibrinolysis and the so far undescribed pattern of hyperfibrinolysis associated with the most severe stage of lymphoma.

Comparative analysis of the aberrant immunophenotype and clinical characteristics in dogs with lymphoma: a study of 27 cases

Introduction

Aberrant lymphoma phenotypes are frequently found in dogs, but the clinical implications are sparse.

Methods

Twenty-seven dogs with aberrant lymphoma diagnosed using flow cytometry between 2017 and 2023 were analyzed. Major paraneoplastic syndromes, prognostic factors, and clinical features of lymphoma were compared to their immunophenotypes.

Results

Twenty-seven dogs had aberrant immunophenotypes, with MHCII- (48%) and CD3+/CD21+ (44%) being the most commonly identified aberrancies. In B-cell lymphoma, the most frequent aberrancies were MHC II- (53%), CD3+/CD21+ (41%), CD34+ (24%), and CD79a- (24%). Meanwhile, in T-cell lymphoma, CD3+/CD21+ (63%), CD4-/CD8-(50%), CD5- (50%), and CD45- (50%) were the most common. The platelet-neutrophil ratio was significantly higher in the CD3+/CD21+ group than in the other groups, where either one or both markers were not expressed (55.23 ± 39.64; 18.72 ± 14.95, respectively; p = 0.001). Serum albumin concentration was significantly lower in the MHCII-group (2.59 g/dL, 95% CI 2.31-2.87) than in the MHCII+ group (3.06 g/dL, 95% CI 2.88-3.23; p = 0.009). CD34 expression showed significant correlations with cranial mediastinal mass, WHO clinical substage, and fever (p = 0.028, p = 0.041, and p = 0.047, respectively). MHCII expression was correlated with adverse reactions to chemotherapy, cranial mediastinal masses, and fever (p = 0.009, p = 0.023, and p < 0.001, respectively). No statistically significant differences in the survival period were observed for any of the phenotypic aberrancies.

Conclusion

Aberrant lymphomas are common in dogs. Some clinical prognostic factors that significantly correlate with aberrant immunophenotypes have been identified and can be applied clinically.

Evaluation of Haemostasis in Dogs Affected by Resectable Malignancy

Dogs with neoplasm are at risk of thrombosis, yet there is no information on the haemostatic alterations that may result from the surgeries performed to remove neoplastic masses. The aim of this study was to observe the characteristics of haemostasis in dogs undergoing surgery to remove a malignancy by means of rotational thromboelastometry and thrombin generation. Haemostasis was assessed immediately before surgery (T0), 24 h after surgery (T1), and two weeks after surgery (T2). Statistically significant differences were found between the thromboelastometric parameters at T0 vs. T1, with increases observed in MCF, the α angle, and G parameters in the ex-TEM and in-TEM profiles. In the thromboelastometric analysis performed after surgery differences were identified between T1 and T2, with a decrease observed in parameters such as CFT, MCF, the α angle, and G. Between T0 and T2, only a significant decrease in CT was detected in the fib-TEM profile. No differences were found in the comparison among the results obtained via thrombin generation. In dogs with resectable malignancies, the surgeries performed to remove cancer affected coagulation, causing a tendency towards hypercoagulability. The interference with coagulation was transient, and 2 weeks after surgery, the thromboelatometric results returned to those obtained before surgery (T0).

Comparison of assessment of coagulation in healthy dogs by the TEG 6s and TEG 5000 viscoelastic analyzers

The TEG 6s (Haemonetics) point-of-care viscoelastic analyzer is portable, compact, simple to use, and has the potential for rapid viscoelastic analysis that can guide the treatment of veterinary patients at the site of care. Although approved for use in people, the TEG 6s has yet to be evaluated for hemostatic analysis in veterinary medicine. Citrated whole blood (CWB) was collected from 27 healthy dogs. An aliquot of CWB from each dog was diluted by 33% with an isotonic crystalloid, representing an in vitro model of hemodilution. Unaltered and diluted CWB samples were analyzed using 2 TEG 6s and 6 TEG 5000 (Haemonetics) analyzers. The 6 TEG 5000 analyzers ran duplicate analyses of either unaltered or diluted samples using 1 of 3 reagents (Haemonetics): Kaolin TEG, RapidTEG, or TEG Functional Fibrinogen. Duplicate TEG 5000 analyses were averaged and compared with a single TEG 6s analysis. Lin concordance correlation coefficient and Bland-Altman plots were used to evaluate agreement of reaction time, kinetic time, alpha angle, maximum amplitude (MA), and G value (G) for samples activated with Kaolin TEG, and agreement of MA for samples activated with RapidTEG between the 2 machines. Overall, agreement between the TEG 6s and TEG 5000 analyzers was poor. Viscoelastic measurements by the TEG 6s and TEG 5000 in healthy dogs were not all interchangeable. Agreement was satisfactory only for MA and G measurements of diluted blood samples activated with Kaolin TEG, and MA measurements for both unaltered and diluted blood samples activated with RapidTEG.

The impact of peripheral blood cell ratios in dogs with diffuse B-cell small lymphocytic lymphoma treated with CHOP protocol

In this study, pre-chemotherapy hematological values of 14 dogs diagnosed with diffuse B-cell small lymphocytic lymphoma were compared with the hematological data of 26 healthy dogs. Neutrophil/lymphocyte ratio (NLR), lymphocyte/monocyte ratio (LMR), platelet/lymphocyte ratio (PLR) and platelet/neutrophil ratio (PNR) were evaluated between two groups. Anemia and an increased total leukocyte count were observed in dogs with lymphoma compared to healthy ones. The PNR value was found to be significantly lower in dogs with lymphoma, It was concluded that more comprehensive studies studies are needed to clearly understand the diagnostic and prognostic importance of hematological parameters in B-cell small lymphocytic lymphoma of dogs.

Use of Thromboelastography in Clinical Practice

Viscoelastic testing, such as thromboelastography or thromboelastometry, is performed on whole-blood samples, which include both soluble plasma factors as well as blood cells and platelets bearing tissue factor and phospholipid. This methodology allows identification of fibrinolysis and can provide analysis of platelet function. Viscoelastic testing has become increasingly accessible and popular in emergency and critical care settings in recent years and can provide important information for the diagnosis and management of patients with hemostatic disorders. This article discusses the principles and interpretation of viscoelastic testing, application to small animal emergency and critical care medicine, and potential advantages and disadvantages.

Peripheral blood cell ratios as prognostic factors in canine diffuse large B-cell lymphoma treated with CHOP protocol

Diffuse large B-cell lymphoma (DLBCL) is the most common haematopoietic tumour in dogs and recognized as clinical model for its human counterpart. Recently, neutrophil-to-lymphocyte (NLR) and lymphocyte-to-monocyte (LMR) ratios have been shown to predict time-to-progression (TTP) and lymphoma-specific survival (LSS) in dogs with DLBCL treated with CHOP-based chemotherapy. We retrospectively evaluated in 59 dogs diagnosed with DLBCL the prognostic value of haematological parameters and derived ratios: NLR, LMR, platelet-to-lymphocyte (PLR) and platelet-to-neutrophil (PNR) ratios for TTP, LSS and associated secondary end-points (time-to-progression-rate [TTPR] and lymphoma-specific survival-rate [LSSR]) as rates at 180 and 365 days. PNR is an independent prognostic marker (p ≤ .001) for TTPR/180 and 365 days, dogs with a PNR above 0.032 were more likely to progress before 180 days (sensitivity 46.5%, specificity 87.5%, p = .004). On univariate analysis, NLR showed a prognostic significance for LSSR/180 (p = .006) and LSSR/365 (p = .009). A baseline NLR value below 7.45 was positively associated with survival at 180 days (sensitivity 52%, specificity 85.3%, p = .025). The presence of substage b, was associated with early progression and decreased survival at 180 days (p = .031). Anaemia significantly reduced LSSR at 365 days (p = .028). This is the first study evaluating PLR and PNR in canine DLBCL and demonstrates that PNR could be a predictor of early lymphoma progression. Since peripheral blood cell composition can be affected by several non-oncological causes, the development of larger multicenter studies with homogeneous inclusion criteria could help to better determine the true predictive values of blood cell ratios in dogs' DLBCL treated with CHOP chemotherapy.

Profiling of the Risk Factors and Designing of a Model to Identify Ischemic Stroke in Patients with Non-Hodgkin Lymphoma: A Multicenter Retrospective Study

BACKGROUND

The occurrence of ischemic stroke in patients with non-Hodgkin lymphoma (NHL) is not well understood. This study aimed to determine independent risk factors to identity ischemic stroke in non-Hodgkin lymphoma-associated ischemic stroke (NHLAIS) patients.

METHODS

This retrospective study was conducted on NHLAIS patients and age- and gender-matched NHL patients. We collected clinical data of patients in both groups and used multiple logistic regression analysis to identify independent risk factors for NHLAIS. A receiver operating characteristic (ROC) analysis was used to establish an identification model based on potential risk factors of NHLAIS.

RESULTS

Sixty-three NHLAIS patients and 63 NHL patients were enrolled. Stage III/IV (58/63, 92.1%) and multiple arterial infarcts (44/63, 69.8%) were common among NHLAIS patients. Notably, NHLAIS patients had higher levels of serum fibrinogen (FIB), D-dimer, and ferritin (SF) and prolonged thromboplastin time and prothrombin time (PT) compared with NHL patients (all p < 0.05). Elevated FIB, D-dimer, and SF and prolonged PT were independent risk factors for NHLAIS. The area under the ROC curve of the identification model of NHLAIS patients was largest compared to that of other risk factors (0.838, 95% confidence interval: 0.759-0.899) (p < 0.05).

CONCLUSION

This study reveals that elevated serum FIB, D-dimer, and SF and prolonged PT are potential independent risk factors of NHLAIS. The identification model established in this study may help monitor NHL patients who are at high risk of developing NHLAIS.

Evaluation of an automated point-of-care test system for measuring thrombin-antithrombin complex in dogs

OBJECTIVE

To evaluate the utility of the chemiluminescent enzyme immunoassay (CLEIA) method for point-of-care (POC) measurement of canine plasma thrombin-antithrombin complex (TAT) concentration.

ASSESSMENT AND MAIN RESULTS

Plasma TAT concentration was measured in 54 healthy dogs and in 72 dogs with various diseases. A significant correlation was found between TAT concentration measured by CLEIA and that measured by an ELISA that was previously used in dogs. The upper limit of the reference value of TAT concentrations measured by CLEIA was determined to be 0.2 ng/mL based on the TAT concentration in 54 healthy dogs. TAT concentrations exceeded the reference interval in a portion of dogs when a hypercoagulable state may be present.

CONCLUSIONS

Canine plasma TAT concentrations measured using CLEIA were correlated with that measured using ELISA. Hence, a POC testing instrument may be used for early detection of activation of thrombin generation in emergency and critical care settings.

American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines: Small animal

OBJECTIVES

To systematically review available evidence and establish guidelines related to the risk of developing thrombosis and the management of small animals with antithrombotics.

DESIGN

Standardized, systematic evaluation of the literature (identified by searching Medline via PubMed and CAB abstracts) was carried out in 5 domains (Defining populations at risk; Defining rational therapeutic use; Defining evidence-based protocols; Refining and monitoring antithrombotic therapies; and Discontinuing antithrombotic therapies). Evidence evaluation was carried out using Population, Intervention, Comparison, Outcome generated within each domain questions to address specific aims. This was followed by categorization of relevant articles according to level of evidence and quality (Good, Fair, or Poor). Synthesis of these data led to the development of a series of statements. Consensus on the final guidelines was achieved via Delphi-style surveys. Draft recommendations were presented at 2 international veterinary conferences and made available for community assessment, review, and comment prior to final revisions and publication.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Over 500 studies were reviewed in detail. Worksheets from all 5 domains generated 59 statements with 83 guideline recommendations that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations.

CONCLUSIONS

Overall, systematic evidence evaluations yielded more than 80 recommendations for the treatment of small animals with or at risk of developing thrombosis. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 1-Defining populations at risk

OBJECTIVES

Thrombosis is a well-recognized phenomenon in dogs and cats with a significant impact on morbidity and mortality. Despite growing awareness of thrombosis and increased use of antithrombotic therapy, there is little information in the veterinary literature to guide the use of anticoagulant and antiplatelet medications. The goal of Domain 1 was to explore the association between disease and thrombosis in a number of conditions identified as potential risk factors in the current veterinary literature, to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. Revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated included immune-mediated hemolytic anemia, protein-losing nephropathy, pancreatitis, glucocorticoid therapy, hyperadrenocorticism, neoplasia, sepsis, cerebrovascular disease, and cardiac disease.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Of the diseases evaluated, a high risk for thrombosis was defined as dogs with immune-mediated hemolytic anemia or protein-losing nephropathy, cats with cardiomyopathy and associated risk factors, or dogs/cats with >1 disease or risk factor for thrombosis. Low or moderate risk for thrombosis was defined as dogs or cats with a single risk factor or disease, or dogs or cats with known risk factor conditions that are likely to resolve in days to weeks following treatment.

CONCLUSIONS

Documented disease associations with thrombosis provide the basis for recommendations on prescribing provided in subsequent domains. Numerous knowledge gaps were identified that represent opportunities for future study.

Carbon Monoxide-Releasing Molecule Enhances Coagulation and Decreases Fibrinolysis in Normal Canine Plasma

The dog is an important companion animal and also purpose-bred for research studies. Coagulopathies in dogs are common, although the availability of blood products for therapy is inconsistent throughout the profession. A pro-coagulant therapeutic that is readily available and easily stored would be useful for the treatment of coagulopathies. Tricarbonyldichlororuthenium (II) dimer [Carbon monoxide-releasing molecule-2 (CORM-2)] acts as a prothrombotic agent in plasma by increasing the velocity of clot formation and clot strength, and by decreasing the clot's vulnerability to fibrinolysis. We sought to test CORM-2's effect on coagulation and fibrinolysis in vitro in canine plasma using thromboelastography. Measures of the rate of clot formation and clot strength in plasma without CORM-2 were highly correlated with fibrinogen concentration. We found that CORM-2 significantly enhanced the rate of clot formation and clot strength and significantly reduced the rate of fibrinolysis and the clot lysis time. The per cent change in rate of clot formation and clot strength was not significantly correlated with fibrinogen concentration, indicating that CORM-2's pro-coagulant effect is not dependent on fibrinogen concentration. This study corroborates studies in other species that show that CORM-2 is pro-coagulant in plasma, and lays the groundwork for developing CORM-2 as a therapeutic agent for canine coagulopathies. Future studies will evaluate the effect of CORM-2 on whole blood both in vitro and in vivo.

Dissecting the regulatory microenvironment of a large animal model of non-Hodgkin lymphoma: evidence of a negative prognostic impact of FOXP3+ T cells in canine B cell lymphoma

The cancer microenvironment plays a pivotal role in oncogenesis, containing a number of regulatory cells that attenuate the anti-neoplastic immune response. While the negative prognostic impact of regulatory T cells (Tregs) in the context of most solid tissue tumors is well established, their role in lymphoid malignancies remains unclear. T cells expressing FOXP3 and Helios were documented in the fine needle aspirates of affected lymph nodes of dogs with spontaneous multicentric B cell lymphoma (BCL), proposed to be a model for human non-Hodgkin lymphoma. Multivariable analysis revealed that the frequency of lymph node FOXP3⁺ T cells was an independent negative prognostic factor, impacting both progression-free survival (hazard ratio 1.10; p = 0.01) and overall survival (hazard ratio 1.61; p = 0.01) when comparing dogs showing higher than the median FOXP3 expression with those showing the median value of FOXP3 expression or less. Taken together, these data suggest the existence of a population of Tregs operational in canine multicentric BCL that resembles thymic Tregs, which we speculate are co-opted by the tumor from the periphery. We suggest that canine multicentric BCL represents a robust large animal model of human diffuse large BCL, showing clinical, cytological and immunophenotypic similarities with the disease in man, allowing comparative studies of immunoregulatory mechanisms.