Feline leukaemia virus status of Australian cats with lymphosarcoma.
OBJECTIVE
To determine the FeLV status of sera and tumours from Australian cats with lymphosarcoma in relation to patient characteristics, tumour characteristics (tissue involvement, histological grade and immunophenotype), haematological and biochemical values.


METHODS
Prospective study of 107 client-owned cats with naturally-occurring lymphosarcoma.


METHODS
An ELISA was used to detect FeLV p27 antigen in serum specimens collected from cats with lymphosarcoma. A PCR was used to detect FeLV DNA in formalin-fixed, paraffin-embedded tissue sections containing neoplastic lymphoid cells. The PCR was designed to amplify a highly conserved region of the untranslated long terminal repeat of FeLV provirus.


RESULTS
Only 2 of 107 cats (2%), for which serum samples were available, were FeLV-positive on the basis of detectable p27 antigen in serum. In contrast, 25 of 97 tumours (26%) contained FeLV DNA. Of the 86 cats for which both PCR and ELISA data were available, 19(22%) had FeLV provirus in their tumours but no detectable circulating FeLV antigen in serum, while 2 (2%) had FeLV provirus and circulating FeLV antigen. FeLV PCR-positive/ELISA-negative cats (19) differed from PCR-negative/ELISA-negative cats (65) in having fewer B-cell tumours (P = 0.06), more non B-/non T-cell tumours (P = 0.02) and comprising fewer non-Siamese/Oriental pure-bred cats (P = 0.03).


CONCLUSIONS
The prevalence of FeLV antigen or provirus was considerably lower in our cohort of cats compared with studies of lymphosarcoma conducted in the Northern hemisphere. This suggests that factors other than FeLV are important in the development of lymphosarcoma in many Australian cats. No firm conclusions could be drawn concerning whether FeLV provirus contributed to the development of lymphosarcoma in PCR-positive/ELISA-negative cats.
Gabor
L J
LJ
Department of Veterinary Anatomy and Pathology, The University of Sydney, New South Wales, Australia.
Jackson
M L
ML
Trask
B
B
Malik
R
R
Canfield
P J
PJ
D000818:Animals; D000956:Antigens, Viral / Q000302:isolation & purification*; D002371:Cat Diseases / Q000453:epidemiology* / Q000821:virology*; D002415:Cats; D004279:DNA, Viral / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology; D005256:Leukemia Virus, Feline / Q000276:immunology*; D016582:Leukemia, Feline / Q000453:epidemiology / Q000821:virology; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D009517:New South Wales / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D011446:Prospective Studies; D012191:Retroviridae Proteins / Q000235:genetics / Q000276:immunology
D000956:Antigens, Viral; D004279:DNA, Viral; D015683:Gene Products, gag; D012191:Retroviridae Proteins; C117471:feline leukemia virus protein p27