CD8+ T CELLS ASSOCIATE WITH FORMING GLANDULAR NODULES IN TOXOPLASMA GONDII-INDUCED PROSTATIC HYPERPLASIA AND HUMAN BPH

Background: Chronic inflammation is the most common histological feature in Benign Prostatic Hyperplasia (BPH), and T cells are a key component of immune infiltrate. Advanced BPH is commonly associated with the formation of nodules, but it remains unclear whether a link exists among T cell infiltration, nodular development, and BPH progression. Using a Toxoplasma gondii (T. gondii) model and human specimens, we characterize the subtypes of T cells present during prostatic hyperplasia and their association with nodular development of the prostate. Methods: Male CBA/j mice were intraperitoneally infected with T. gondii parasites, and flow cytometry was performed on the prostate to quantify the number of CD4+ and CD8+ T cells. Histology was used to score microglandular hyperplasia (MGH), and immunofluorescence was used to quantify and examine the locality of CD4+ and CD8+ T cells and compared that to human BPH tissue. Results: We found that infecting male mice with T. gondii resulted in an increase of both CD4+ and CD8+ T cells in the prostate acutely and that CD8+ cells remained sustained at chronically. We also established the presence of glandular nodule formation at this timepoint through hematoxylin and eosin (H&E) staining. Immunofluorescence revealed that CD8+ cells were found proximal to forming glandular nodules relative to non-nodular glands. We also found more CD8+ cells localized to non-nodular glands in nodular BPH tissue versus non-nodular BPH tissue. Finally, we discovered a higher prevalence of CD8+ cells in T. gondii IgG+ patients than in IgG- patients. All T. gondii IgG+ patients exhibited nodular BPH, whereas all but one IgG- patient exhibited non-nodular BPH. Conclusions: This study is the first to investigate the presence and location of CD4+ and CD8+ T cells within nodular and non-nodular BPH glands. We found an association of the presence of CD8+ T cells with nodular progression. This association held true in human prostate tissue. Translationally, CD8+ T cells may enhance nodular BPH progression, and T. gondii infection may promote this CD8+ T cell-mediated response.