Immune response in hormonally-induced prostatic hyperplasia in the dog

We induced prostatic enlargement in castrated dogs using either androgen al one or androgen combined with estrogen, Ln addition to previously reported hyperplastic changes, marked infiltration with immune effector cells was ob served. This mononuclear cell infiltrate was phenotypically characterized u sing CD3 as pan T-lymphocyte marker, CD79 for B-lymphocytes, MAC378 for mac rophages, and antibodies against kappa- and lambda-immunoglobulin (Ig) ligh t chains for plasma cells. The majority of inflammatory cells (>80%) in the mononuclear infiltrates were T-lymphocytes and the numbers correlated with the degree of inflammation. The B-lymphocytes were found particularly in a reas with marked follicular formation and diffuse infiltration, whereas the re were only a few positive cells (<10%) in areas with a moderate or slight inflammation. Macrophages were found primarily in areas with atrophic and cystic changes with and without inflammation. The expression of lambda-Ig-p ositive cells depended on the degree of inflammation (5-10%), whereas immun oreactivity of kappa-Ig did not correlate with the extent of inflammatory r eaction. Our present findings together with the evaluation of longitudinal biopsies of hormonally-induced BPH indicate that hyperplasia preceded cell- mediated and humoral immune response. (C) 2001 Elsevier Science B.V. All ri ghts reserved.