Monocytes-macrophages and cytokines/chemokines in fine-needle aspiration biopsy cultures - Enhanced interleukin-1 receptor antagonist synthesis in rejection-free kidney transplant patients

Background. Monocytes-macrophages are found within kidney allografts during the first days after surgery, where they perform ''housekeeping'' tasks, participate in postreperfusion injury, and act as antigen-presenting cells, as well as become involved in the effector phase of acute rejection, They also seem to play a prominent role in chronic rejection, We quantified their presence in fine-needle aspiration biopsies and studied the growth factors that, we hypothesized, would mark the different implications of the presence of monocytes-macrophages. Methods. Fine-needle aspiration biopsies were obtained from 56 adult renal transplants and analyzed for CD14(+) using the alkaline phosphatase-anti-alkaline phosphatase procedure, Thirty-three patients were studied on the production of interleukin (IL)-1 receptor antagonist (IL-1ra), IL-6, IL-8, macrophage colony-stimulating factor, monocyte chemotactic protein 1, and macrophage inflammatory protein 1 alpha by aspiration biopsies cultures using enzyme-linked immunosorbent assay techniques. Results. CD14(+) cells were present at significantly higher numbers in steroid-resistant acute rejections but also during the first days after surgery, especially if acute tubular necrosis was present, We found a significantly higher production of IL-1ra by rejection-free patients compared with acutely rejecting patients, and this difference was already established on day 7 after surgery (10+/-10.5 days before rejection). Conclusions. Monocytes-macrophages are present at higher numbers in aspiration biopsies of kidney transplant patients suffering either acute tubular necrosis or steroid-resistant rejections, but they are present during the first days after transplant in stable patients, too, The production of IL-1ra is significantly up-regulated in stable patients, which suggests that monocytes-macrophages may constitute an early key factor in the down-regulation of the anti-allograft immune response.