Immunology of the rheumatoid joint

rheumatoid arthritis is a common autoimmune disorder of the joints that affects about 1% of the population worldwide more often women than men the exact causes of the disease are unknown but an individual's risk is thought to be increased by a combination of genetic and environmental factors many of the genes associated with rheumatoid arthritis are involved in immune system function non genetic risk factors include age diet infectious agents and smoking in an autoimmune disorder such as rheumatoid arthritis the immune system mistakenly attacks and destroys the body's own cells and tissues which immunologists refer to as self and this autoimmunity can begin many years before joint symptoms are noticed doctors can use blood tests to identify this preclinical phase by the presence of multiple factors in the blood such as Auto antibodies and inflammatory factors these early auto antibodies are thought to first develop outside of the joints possibly in the gut mouth or lungs environmental factors such as smoking can modify our self proteins making them targets for the immune system one particular modification is called citral ination when the immune system recognizes these modified self proteins it leads to a breach of self tolerance and the production of autoreactive b-cells and auto antibodies and later or two reactive t-cells the hallmarks of autoimmune disease by the time that symptoms appear the immune response has intensified and the antibodies produced target abroad a range of self proteins but it's only in some patients that this systemic autoimmunity progresses to joint inflammation which is possibly triggered by an increase in joint permeability and increased access to antibodies looking out how to prevent this progression is a major goal for scientists in patients who do develop joint disease the small joints of the hands and feet are most commonly affected after entering a joint immune cells and Auto antibodies bind to modified self proteins in the cartilage bone and lining of the joint of the synovium this induces an inflammatory response and activate cells in the joint such as macrophages neutrophils and osteoclasts as well as blood monocytes activated monocytes differentiate into yet more macrophages which together with other cells in the joint produce soluble inflammatory factors known as cytokines drugs targeting these cytokines are highly effective treatments for many patients left unchecked however damage caused by the inflammatory environment can expose new self antigens to the immune system continuing the cycle at this stage the first clinical symptoms of joint pain swelling and warmth appear some patients recover but most commonly patients develop a chronic destructive disorder as the disease progresses dendritic cells display the newly exposed self antigens and activate t-cells in the joint itself or in the local lymph node in addition b-cells infiltrate the joint where they proliferate and produce antibodies and other factors further amplifying the autoimmune response cells in the joint lining called fibroblasts like synovial sites also proliferate and grow into the joint space spreading across to the cartilage surface these cells secrete matrix degrading enzymes which erode the cartilage tissue bone is also eroded as osteoclasts which contribute to normal bone turnover become hyperactive a t-bone erosion cartilage destruction and joint swelling caused severe pain restrict movement of the joint and in the worst cases can cause joint deformities and as well as the joints other organs and body systems can be affected by the ongoing information for example information in the blood vessels can lead to heart disease so early and aggressive therapy is recommended to prevent these systemic complications by further understanding the immune markers and mechanisms of rheumatoid arthritis it's hoped that targeted interventions could ultimately change the course of the disease

Channel: nature video

Views: 226,480

Keywords: nature, science, animation, rheumatoid, arthritis, inflammation, disease, joints, rheumatology, immunology, therapy

Id: nYjzl3Xc_0E

Length: 5min 22sec (322 seconds)

Published: Thu Jan 28 2016