Serum Thymidine Kinase Activity as a Useful Marker for Bovine Leukosis

Abstract

Abstract. Serum thymidine kinase (TK) activity has recently been evaluated as a serum marker for human and canine hematopoietic neoplasms. The purpose of the current study was to establish the significance of serum TK activity in the diagnosis of bovine leukosis. The discrimination value for TK activity was set at 5.4 U/l based on the receiver operating characteristic curve. In the group of clinically healthy cows, only 2 out of 83 cows (2.4%) had serum TK activity above the discrimination value. In contrast, 19 out of 20 cows (95.0%) with bovine leukosis showed serum TK activity above the discrimination value, although only 7 of 79 (8.9%) cows diagnosed with diseases other than bovine leukosis showed elevated serum TK activity. Thymidine kinase activities of all Bovine leukemia virus-positive cows with or without lymphocytosis were below the discrimination value. Sensitivity and specificity of measuring serum TK activity as a diagnostic tool for bovine leukosis was 95.0% and 95.9%, respectively. Results indicate that serum TK activity may be a marker for bovine leukosis.

Utility of Serum Thymidine Kinase Activity Measurements for Cases of Bovine Leukosis with Difficult Clinical Diagnoses

“…The reportable range of the assay was 0.5 to 1,000 U/l. TK activities of 20 cattle among 60 with BL have been already reported in a previous report [11].…”

“…Serum TK concentrations increase in patients with several types of hematopoietic tumors [4,5,8,9]. Serum TK activity is useful for detecting, grading and monitoring tumors in lymphoma and leukemia patients, may also be helpful in diagnosing and monitoring canine lymphoma and leukemia [13] and is also a possible marker of bovine leukosis [11]. However, BLV infection with no onset of BL would not induce TK activities [11].…”

“…Serum TK activity is useful for detecting, grading and monitoring tumors in lymphoma and leukemia patients, may also be helpful in diagnosing and monitoring canine lymphoma and leukemia [13] and is also a possible marker of bovine leukosis [11]. However, BLV infection with no onset of BL would not induce TK activities [11]. The present study evaluated the clinical usefulness of serum TK activity for diagnosis of 'BL with difficult diagnosis' by comparing TK activity in cows with 'BL with difficult diagnosis' to that in cows with clinically confirmed BL, those with lymphadenopathy, or those with other diseases.…”

“…Serum thymidine kinase (TK) activity has been evaluated as a serum marker for human and canine hematopoietic tumors [4,5,8,9,14] and is potentially a marker for BL with higher sensitivity than FNA [11]. In our previous study, 19 of 20 cows (95.0%) with BL showed serum TK activities above the cut-off point (>5.4 IU/l) [10].…”

Calf Form Bovine Leukosis with Lameness in a Holstein Heifer

“…The present case showed slightly higher activities of total LDH, LDH-2, and LDH-3. Serum TK activity has also been used as a bovine leucosis biomarker [13], and the TK activity of the present case was higher than established values for healthy animals (5.4 IU/l) [13]. These combined results suggest that measurement of activities of both serum LDH isozymes and TK can be used as markers of calf form bovine leukosis as well as enzootic bovine leukosis.…”