Background. Autoimmune diseases and neoplasia have been associated as occurring simultaneously in individuals. This study evaluated the association between the simultaneous occurrence of canine lymphoma and various immune-mediated diseases.
Methods. The Veterinary Medical Data Program, a national disease data registry for veterinary schools, was examined. The following immune-mediated disease categories were evaluated: lupus disorders, pemphigus disorders, autoimmune polyarthritis, immune-mediated hemolytic anemia, and immune-mediated thrombocytopenia. Odds ratios with 99% confidence intervals were calculated for the occurrence of lymphoma and each of the immune-mediated disorder categories.
Results. Only dogs with immune-mediated thrombocytopenia had a statistically significantly increased odds ratio (5.61; 99% confidence interval, 4.16-7.57) for the occurrence of lymphoma versus the general population. This association still was observed for immune-mediated thrombocytopenia when stratified by age, sex, and neutering status.
Conclusion. Dogs with immune-mediated thrombocytopenia had a greater occurrence of lymphoma than dogs without immune-mediated thrombocytopenia. Cancer 1992; 70:2334-2337.