Genomic organization of the T-cell receptor gamma gene and PCR detection of its clonal rearrangement in canine T-cell lymphoma/leukemia.
ABSTRACT Because the T-cell receptor gamma (TCRgamma) gene is rearranged at an early stage of T-cell development in both TCRalphabeta and TCRgammadelta lineages, it has been preferentially targeted to detect T-cell clonality in human lymphoma/leukemia. We isolated 22 independent cDNA clones encoding canine TCRgamma and the following analysis of nucleotide sequences using the dog genome database revealed that the canine TCRgamma locus contains at least four repertories of variable genes that can be organized into two distinct subgroups and six repertories of joining genes belonging to two distinct subgroups according to the nucleotide sequence similarity. The findings allowed us to design PCR primers that were directed to the conserved or specific nucleotide sequences for each subgroup of variable and joining genes. By using four different combinations of primers, a PCR-based analysis was performed on cell samples collected from T-cell lymphoma/leukemia and B-cell lymphoma cases and hyperplastic and normal lymph nodes. All cell samples from 11 T-cell malignancy cases exhibited clonal amplification by two out of four primer combinations. This finding was considered to be valuable in PCR-based analysis for detecting T-cell clonality in canine lymphoma/leukemia.
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ABSTRACT: Lymphoma is the most common hematopoietic malignancy in dogs. Diagnosis of lymphoma is classically performed by morphological assessment and immunohistochemistry. But some cases in the early stage are difficult to distinguish and need more objective and accurate methods. So, Polymerase chain reaction (PCR) for antigen receptor rearrangements (PARR) and flow cytometric immunophenotype of lymphoma have been developed continuously. In this study, we performed these two methods to classify lymphoma type in 3 cases. According to PARR analysis, B cell origin lymphoma was diagnosed in two of three cases by testing PBMC and lymph node. All fine needle aspiration (FNA) samples of lymph nodes had high expression of CD21 on >88% of total cell population and PBMC samples also showed high expression of CD21 on >30% of total lymphocytes in those two cases, while the expression of CD3, CD4 and CD8 was absent. These results suggest that concurrent use of PARR and flow cytometric immunophenotype is more effective and valuable tool for the diagnosis and monitoring of canine lymphoma patients.Korean Journal of Veterinary Service. 09/2011; 34(3).
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ABSTRACT: The objectives of this study were to detect clonal rearrangements of antigen receptor genes by polymerase chain reaction (PCR) assay and minimal residual disease (MRD) in clinical complete remission of chemotherapeutic-treated dogs. For PCR assays to determine clonality for antigen receptor rearrangement genes and MRD from cytologic and peripheral blood samples of 14 dogs with lymphoma either before chemotherapy and during remission, clonality was detected in 13 of the lymphomas before treatment. MRD was demonstrated in seven dogs with lymphoma during remission. Detection of MRD during remission in canine lymphoma using PCR technique is considered as a useful tool for prognosis and monitoring relapsing disease.Comparative Clinical Pathology 01/2014;
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ABSTRACT: Definitive diagnosis of histiocytic sarcoma (HS) in dogs is relatively difficult by conventional histopathological examination because objective features of HS are not well defined. Quantitative analysis of mRNA expression of selected cellular surface antigens (SAs) specific to HS in dogs can facilitate objective and rapid diagnosis. Dogs with HS (n = 30) and dogs without HS (n = 36), including those with other forms of lymphoma (n = 4), inflammatory diseases (n = 6), and other malignant neoplasias (n = 26). Retrospective clinical observational study. Specimens were collected by excisional biopsy, needle core biopsy, or fine needle aspiration. To determine HS detection efficacy, mRNA expression levels of selected SAs specific to HS in dogs, including MHC class IIα, CD11b, CD11c, and CD86, were quantitatively analyzed using real-time quantitative polymerase chain reaction. Each SA mRNA expression level was significantly higher in HS dogs than in non-HS dogs (P = .0082). Cutoff values for discriminating between HS and non-HS dogs based on these expression levels were calculated on the basis of receiver-operating characteristic analysis. Accuracy of the cutoff values, including MHC class IIα, CD11b, CD11c, and CD86, was 87.9, 86.4, 86.4, and 84.8%, respectively. Our results suggest that quantitative analysis of mRNA expression of the selected SAs could be an adjunctive diagnostic technique with high diagnostic accuracy for HS in dogs. Substantial investigation is required for exclusion of diseases with similar cell types of origin to lymphoma.Journal of Veterinary Internal Medicine 01/2014; 28(1):204-210. · 2.06 Impact Factor