[Biopathology of the synovial membrane in psoriatic arthritis].

The study of the pathobiology of the synovium in psoriatic arthritis has identified morphological, cellular and molecular differences from rheumatoid arthritis. Here we review some processes that are more characteristic or have greater intensity in psoriatic arthritis, such as vascular patterns, angiogenesis and the role of the innate immune cells. We highlight in detail the finding that interleukin (IL) 17, whose role in the pathophysiology appears relevant, is produced mainly by mast cells and neutrophils in different target tissues of psoriatic arthritis, as well as the synovium, skin and axial joints. On the other hand, we try to understand the complexity of the study of the pathophysiology of psoriatic synovitis, which presents multiple interactions between cells and molecules that can vary depending on the phenotype and the stage of the disease in each patient and requires a complex methodological approach.