The Immunophenotype of Peripheral Blood Lymphocytes in Clinically Healthy Dogs and Dogs with Lymphoma in Remission

Abstract

Lymphoma is a common cancer of dogs that frequently is treated with chemotherapy or radiation therapy. Response to therapy is variable and currently available diagnostic tests do not reliably predict response to therapy. Treatment for lymphoma often results in lymphopenia, but it is unknown whether the changes in circulating lymphocytes result from generalized or specific reduction of lymphocytes. In this study, blood lymphocytes from 12 clinically healthy dogs, 10 dogs in remission because of treatment for B-cell lymphoma, and 8 dogs in remission from T-cell lymphoma were analyzed by flow cytometry by using a panel of 20 antibodies reactive with canine leukocyte antigens. Results identified similar lymphocyte parameters in treated dogs regardless of the type of lymphoma. Treated dogs had Ͼ50% reduction in blood lymphocyte concentration, and an absolute decrease in most subsets of lymphocytes. Both groups of treated dogs had relative increases in the proportion of CD3 ϩ , T-cell receptor (TCR)␣␤ ϩ , and CD90ϩ lymphocytes, and a decreased proportion of CD45RA ϩ cells. In addition, dogs with T-cell lymphoma in remission had a significant increase in the proportion of CD49d ϩ lymphocytes. These findings were interpreted as representing likely suppression of lymphocyte regeneration by chemotherapy, with a relative increase in the proportion of memory over naïve lymphocytes. Lack of correlation with the T-or B-cell origin of the initial lymphoma suggested that, by using flow cytometric methods, residual circulating neoplastic cells could not be detected. However, the changes in the lymphocyte profile of dogs treated with chemotherapy may have relevance to their immunocompetence.

Effects of Chemotherapy on Immune Responses in Dogs with Cancer

“…Our results differ in some important aspects from those reported recently from immunophenotyping studies in dogs with lymphoma that were evaluated after the completion of chemotherapy. 32 Dogs with lymphoma previously treated with chemotherapy were reported to have .50% reduction in numbers of total lymphocytes and reductions in most lymphocyte subsets, compared with those in control dogs. However, the dogs with lymphoma were not evaluated before the beginning of chemotherapy, so the starting lymphocyte numbers were unknown.…”

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

“…Therefore, to provide information on the role of acquired immunity in CIE, it was considered necessary to evaluate the 3 immune compartments in this work. However, when interpreting the immunophenotypic results, the high variation found in many of the lymphocyte populations of this study should be considered, as this finding suggests a large individual immune variability, as described by many authors in both healthy dogs and dogs with different diseases 16,49‐52 …”

“…However, when interpreting the immunophenotypic results, the high variation found in many of the lymphocyte populations of this study should be considered, as this finding suggests a large individual immune variability, as described by many authors in both healthy dogs and dogs with different diseases. 16,[49][50][51][52] Peripheral blood lymphocytes changes have been described in Crohn's disease and ulcerative colitis in humans [53][54][55] and in dogs with CIE. 16,17 We found a significant increase in the percentage and absolute value of activated peripheral Th lymphocytes in CIE dogs compared with the HC group. We also found an increase in peripheral activated Tc lymphocytes, but not statistically significant.…”

Avaliação leucocitária de cães com linfoma submetidos ao protocolo de Madison-Wisconsin pela técnica convencional e citometria de fluxo

“…Após as primeiras sessões quimioterápicas, mais de 50% dos animais apresentaram-se linfopênicos, fato que atesta a acentuada toxicidade dos quimioterápicos no tecido linfóide, tal qual asseverado por Gauthier et al (2005). Ainda com relação aos leucócitos mononucleares observou-se diminuição progressiva no número absoluto de monócitos, mas os valores médios encontrados se mantiveram dentro dos valores de referência, para a espécie canina, e também não se observaram diferenças significativas entre os momentos.…”