RESUMO
PARR is widely used in the diagnostics of canine lymphoma. In human and veterinary medicine, melting curve analysis (MCA) has successfully been introduced to facilitate the process. Since visual interpretation of melting curves can be rather subjective, the purpose of this study was to develop an objective interpretation of melting curves by calculating the maximum fluorescence decrease (dFmax ) within a defined rise of temperature. Lymph node aspirates and blood of 34 dogs with lymphoma and 28 control dogs were tested. 27/34 lymphoma cases were correctly detected to be monoclonal (sensitivity 79%). 2/28 control dogs showed a monoclonal rearrangement (specificity 93%). B- and T-cell neoplasia were still detectable using DNA amount as low as 10 ng. In serial dilutions of tumor DNA with DNA of normal tonsils, the detection limit was 25% for B-cell lymphomas and 100% for T-cell lymphoma, suggesting that PCR conditions could still be optimized.
Assuntos
Doenças do Cão/diagnóstico , Linfoma/veterinária , Desnaturação de Ácido Nucleico , Animais , Estudos de Casos e Controles , DNA de Neoplasias/química , Doenças do Cão/patologia , Cães , Fluorescência , Linfonodos/patologia , Linfoma/diagnóstico , Linfoma/patologia , Linfoma de Células B/diagnóstico , Linfoma de Células B/veterinária , Linfoma de Células T/diagnóstico , Linfoma de Células T/veterinária , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/veterináriaRESUMO
The diagnosis of canine intestinal lymphoma by morphological examination is challenging, especially when endoscopic tissue specimens are used. The utility of detection of antigen receptor gene rearrangement by polymerase chain reaction (PARR) in canine lymphoma has been well established, but its usefulness to distinguish enteritis and intestinal lymphoma remains unclear. In this retrospective study we assessed clonality of 29 primary canine intestinal lymphoma, 14 enteritis and 15 healthy control cases by PARR analysis, using formalin-fixed, paraffin-embedded full-thickness tissue specimens. We could detect monoclonal rearrangements in 22 of 29 canine intestinal lymphomas [76%; 95% confidence interval (CI) 56-90%] and polyclonal rearrangements in all of the enteritis and healthy control cases (100%; CI 88-100%). We revealed a predominance of T-cell phenotype compared to B-cell phenotype (85%; CI 65-96% and 15%; CI 4-35%, respectively). We showed that PARR analysis contributes to differentiation of canine intestinal lymphoma from enteritis and to phenotyping of lymphomas.
