Expression of interleukin-3 receptor alpha chain (CD123) in plasmacytoid dendritic cells of animal lymph nodes
CD123, plasmacytoid dendritic cells, pathology
Plasmacytoid dendritic cells (pDCs) have been used in human medical studies for the diagnosis and development of antitumor therapies for neoplasms of hematological origin, inflammatory processes and autoimmune diseases. In humans, pDCs are located in the paracortical region of lymph nodes and CD123 (IL-3) is the marker used to detect them. In veterinary medicine, knowledge about these cells and their distribution in normal lymphoid tissues is scarce. In dogs, there is only one study that used the CD123 antibody with immunostaining of pDCs in mammary tumors of dogs. Therefore, this study aims to verify whether this marker is efficient for detecting CD123+ cells in lymph nodes of dogs, cats, cattle and horses and, if in these species, the distribution is similar to that observed in humans. An immunohistochemical examination was performed with monoclonal and polyclonal anti-CD123 antibodies on 10 samples of each species (bovine, feline and canine) and 5 samples of the equine species. The results obtained with monoclonal antibodies were not satisfactory both in the positive control of human tonsil and in animal lymph nodes. With polyclonal antibodies, pDCs were found grouped in clusters or individualized predominantly in the paracortex of all samples (35/35), with variations in other more prevalent regions according to the species, such as in the sinuses and medullary cords in cattle (9/10), peritrabecular sinuses in horses (5/5), perifollicular region of canines (9/10). The results in felines were negative in the majority of cases (7/10), and in positive cases the cells were evident forming clusters in the intrafollicular regions (2/3) and in the paracortex (3/3). It was concluded that CD123 is a valid marker for use in animals, and that these cells, as in humans, are distributed more frequently in the paracortical region of the lymph node.