Research Update from Dr. Petersen into Tick-Borne Disease.
We have successfully identified sporting and hunting dogs at different clinical stages of Lyme Disease and sampled blood from them in the field. We have confirmed our field diagnoses with a specialized assays performed by IDEXX Laboratories. Currently, we analyzed ~70% of our projected sample size of dogs with Lyme exposure. In the lab, we have analyzed the percentage of Natural Killer immune cells and some markers of the activation state of these NK cells in the blood. We have found one subset of these cells increases during canine Lyme disease. The NK cells from dogs with symptomatic Lyme Disease showed a statistically enhanced inflammatory response, indicating that these cells may contribute to clinical disease. We also found a serum cytokine that was elevated in dogs that were asymptomatic after Lyme disease exposure, thus this cytokine could be skewing the NK cell subset toward a less inflammatory phenotype. Our final experiment, which we have troubleshot and obtained working protocols for, will determine if NK cells from dogs in each Lyme subgroup have different cell killing properties. Our overall goal is to determine differences between dogs with asymptomatic versus symptomatic Lyme, in order to better understand which cell types, or inflammatory factors produced by them, are helpful for controlling the disease. Based on these results, therapies targeted towards decreasing NK cell-mediated inflammation, or to increase serum cytokines associated with NK differentiation, may help dogs maintain an asymptomatic state following Lyme Disease exposure. Throughout this study, we have established a good working relationship with the caretakers of the hunting and sporting dogs and have collected enough samples to meet our statistical needs for these experiments. We plan to submit the results of these assays for publication this fall.