The diagnostic value of selected immune parameters in peripheral blood of dogs with malignant mammary tumours - a preliminary study

Introduction

The main adaptive immune cells are T and B lymphocytes and they play key roles in the induction of immune responses against canine mammary tumours. Investigating these cell subpopulations may lead to more precise diagnosis of these malignancies.

Material and Methods

The percentages of CD3+, CD4+ and CD8+ T cells and of CD21+ B cells in the peripheral blood of bitches with malignant mammary tumours were compared with those in the blood of healthy animals. The phenotypic features of peripheral blood leukocytes were evaluated by flow cytometry.

Results

There was a significant difference in the mean percentages of CD3+ lymphocytes between healthy (66.7%) and metastatic dogs (46.1%), and between tumour-bearing non-metastatic (66.6%) and metastatic dogs. There was also a significant difference in CD4+ T helper cell percentages between healthy dogs (40.4%) and dogs with metastases (23.2%), and between the latter and dogs without them (35.5%). In the case of CD21+ lymphocyte subsets, a significant difference was noted between healthy animals (10.9%) and those with metastases (20.1%), and between the latter and patients without metastases (8.5%). There were also significant differences in CD3+/CD21+ ratios between the group with metastases (3.0), the healthy group (7.8), and the group without metastases (8.5). Similarly, a significant difference was noted in CD4+/CD8+ ratios between animals with metastases (1.4), bitches in the control group (2.2), and dogs without metastases (1.9).

Conclusion

Peripheral blood leukocyte phenotypic characteristics are putative novel biomarkers. These findings may be useful in future studies improving mammary tumour diagnostic procedures, especially in metastasis detection.

Peripheral and intestinal T lymphocyte subsets in dogs with chronic inflammatory enteropathy

BACKGROUND

Dysregulated T lymphocyte response is thought to play a key role in chronic intestinal inflammation (CIE).

OBJECTIVES

To evaluate the presence of changes in peripheral and intestinal T lymphocyte subsets and to describe potential immune and inflammatory biomarkers in dogs with CIE.

ANIMALS

Sixteen healthy dogs and 26 dogs were diagnosed with CIE.

METHODS

Prospective case-control study evaluating peripheral and intestinal T lymphocytes using flow cytometry and inflammatory markers obtained from complete blood cell counts.

RESULTS

Dogs with CIE had higher peripheral activated T helper (Th) lymphocytes (87/μL [18-273] CIE, 44/μL [16-162] healthy control (HC, P = .013) and regulatory T cells (Treg; 108/μL [2-257] CIE, 34/μL [1-114] HC, P = .004). In the intestinal epithelium, CIE dogs presented lower percentages of Th (4.55% [1.75-18.67] CIE, 8.77% [3.79-25.03] HC, P = .002), activated Th cells (0.16% [0.02-0.83] CIE, 0.33% [0.05-0.57] HC, P = .03) and CD4/CD8 ratio (0.08 [0.02-0.39] CIE, 0.21 [0.07-0.85] HC, P = .003). Conversely, higher percentage of activated T cytotoxic cells (20.24% [3.12-77.12] CIE, 12.32% [1.21-39.22] HC, P = .04) and interferon-gamma (IFN-γ) producing T lymphocytes (7.36% [0.63-55.83] CIE, 1.44% [0.00-10.56] HC, P = .01) within the epithelium was observed. In the lamina propria the percentage of Treg lymphocytes was higher (6.02% [1.00-21.48] CIE, 3.52% [0.18-10.52] HC, P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Systemic and intestinal immune alterations occur in dogs with CIE suggesting that blood IFN-γ producing T lymphocytes and the systemic immune-inflamation index (SII) could potentially serve as biomarkers for the disease.

Presence of CD3+ and CD79a+ Lymphocytes in the Pituitary Gland of Dogs at Post-mortem Examination

Hypophysitis has been reported occasionally in dogs, with most cases resembling primary lymphocytic hypophysitis in man. Although it is generally assumed that lymphocytes are not present normally in the canine pituitary gland, few studies have investigated this hypothesis. However, lymphocytes are recognized in the pituitary gland of people and horses without signs of pituitary disease. It is unknown to what degree lymphocyte infiltration of the pituitary gland might occur as an incidental finding in dogs. The aim of the present study was to investigate the presence and distribution of lymphocytes in the pituitary gland of dogs without clinical suspicion of pituitary disease. Twenty dogs were subjected to routine necropsy examination. Formalin-fixed and paraffin wax-embedded sections of pituitary were stained with haematoxylin and eosin (HE) or subjected to immunohistochemistry (IHC) using primary antibodies specific for the T-cell marker CD3 and the B-cell marker CD79a. The number of CD3⁺ and CD79a⁺ cells per area unit (CPA) was determined for different pituitary regions. Two dogs had extensive neoplastic lesions in the pituitary gland and were excluded from analysis. In the remaining 18 dogs, occasional scattered CD3⁺ cells were found in the pituitary gland. There was a significant difference in CD3⁺ CPA between pituitary regions (P = 0.001). The highest CD3⁺ CPA was found in the pars tuberalis (median 41.3 cells/mm², interquartile range 20.9-50.5 cells/mm²). In six of the 18 dogs (33%), CD79a⁺ cells were detected in small number (median total cell number 0 cells/section, interquartile range 0-1.0 cells/section). This study shows that T cell, and fewer B cells, may be found in the pituitary gland of dogs without clinical suspicion of pituitary disease. Regional difference in T-cell density, with the highest CD3⁺ CPA in the pars tuberalis, may imply regional immunoregulatory functions in the canine pituitary gland.

Immunophenotype of Peripheral Blood Lymphocytes in Dogs with Inflammatory Bowel Disease

Background

Inflammatory bowel disease (IBD) is common in dogs. Despite the known importance of intestinal lymphocytes in its pathogenesis, little is known about the role of peripheral blood lymphocytes (PBLs) in IBD.

Objectives

The aims of this study were (1) comparison of PBLs analyzed by flow cytometry (FCM) in IBD dogs and healthy controls and (2) comparison of PBLs in IBD dogs at the time of diagnosis and in dogs in clinical remission.

Animals

Whole blood samples of 19 IBD dogs at the time of diagnosis and blood samples of 6 dogs in clinical remission were collected. Ten healthy dogs served as controls.

Methods

In this prospective observational study, PBLs were analyzed with multicolor FCM by staining with a panel of anticanine and cross‐reactive monoclonal antibodies against T‐ and B‐cell differentiation antigens, including CD45, CD3, CD4, CD8α, CD8β, TCRαβ, TCRγδ, CD79αcy, and CD21.

Results

The IBD patients’ PBLs had significantly decreased percentages of TCRγδ⁺ T lymphocytes (median: healthy dogs, 3.32; IBD dogs, 0.97; P = 0.03) and CD21⁺ B cells (median: healthy dogs, 27.61; IBD dogs, 17.26; P = 0.04). There were no significant differences in PBLs between pretreatment and follow‐up samples.

Conclusions and Clinical Importance

The differences between PBLs in healthy and IBD dogs analyzed by FCM indicate an imbalance of lymphocytes with different immunologic functions and emphasize the potential value of this technique in a larger cohort of dogs. The PBLs did not differ between IBD dogs before treatment and clinically well‐controlled dogs after treatment.