Monocyte subpopulations study in patients with plaque psoriasis

Psoriasis is a chronic and systemic, immune-mediated, inflammatory disease, mainly manifested by skin and / or joints lesions, presenting with a wide degree of clinical severity, but generally with great impact on patients' quality of life. Despite advances in the understanding of its pathogenesis, especially regarding the participation of T-lymphocytes and the key role of TNF, the triggering factor of the disease at the molecular level remains unknown, as well as the function of other cell populations. By presenting antigens to T-lymphocytes, monocytes assume an important role in both innate and adaptive immune response. In the last two decades, by using flow cytometry with antibodies against CD14 (receptor for lipopolysaccharide) and CD16 (low affinity receptor for IgG), human blood monocytes were classified into three subpopulations: classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14+CD16++). Under normal conditions the population of classical monocytes corresponds to about 85%, while intermediate to 5.4%, and nonclassical to 9.2%. However, intermediate and nonclassical subsets are increased in various inflammatory situations, such as moderate to severe asthma, colorectal cancer, and rheumatoid arthritis. Despite psoriasis being considered a disease of inflammatory nature, scarce studies evaluating the frequency of subpopulations of monocytes in psoriatic patients are found on current medical literature, and they are restricted to peripheral blood analysis. This study aims to identify the frequency of monocyte subpopulations in blood levels as well as lesional skin of plaque psoriasis patients, and to evaluate their association to cytokines, and clinical disease severity.