Rheumatoid arthritis (RA) is an autoimmune disease where the immune system attacks the body’s joints, causing inflammation, pain, and impaired movement. Factors such as genetics, infection, smoking, and a poorly regulated immune system may contribute to the disease. Females are more likely to develop RA, and infection and genetics may play a role. Smoking doubles the risk of developing RA, and immune cells and cells lining the joints mediate the chronic joint inflammation.
Researchers have not fully uncovered the exact pathophysiology of rheumatoid arthritis (RA), but many discoveries are now expanding the scope of beneficial treatments for this immune system disorder that afflicts nearly 2 million people in the United States. Rheumatoid arthritis is one of a group of diseases, called autoimmune diseases, in which the body’s immune cells mistakenly attack the body’s tissues or organs. In the case of RA, the assault occurs in the joints of the body, producing inflammation, pain and impaired movement. An antibody, called rheumatoid factor, causes the immune system to mistakenly identify the body’s healthy joint tissues as foreign tissue, targeting them for destruction. While the precise cause of rheumatoid arthritis is unknown, several factors appear to be involved, including gender, infection, genetics, smoking, and a poorly regulated immune system.
Females develop rheumatoid arthritis three times as often as males, particularly during the first year after giving birth. Women typically develop the first symptoms during the third and fifth decades of life. Scientists hypothesize that female sex hormones, which tend to promote inflammation, play a role in the pathophysiology of rheumatoid arthritis. The increased incidence of RA in females mirrors the pattern seen with other autoimmune diseases.
Scientists also believe that infection may serve as an initiating event in the pathophysiology of rheumatoid arthritis. In response to an infection, the body produces proteins, called antibodies, which attack foreign particles. If the antibodies aren’t specific enough for bacteria, they can attach themselves to normal body cells that look something like bacteria, disabling the cells and marking them for elimination by immune cells. Many physicians have suspected that parvovirus, rubella, herpes, and mycoplasma, which cause “walking pneumonia,” are potentially instigating agents of RA. Studies, however, have not been able to conclusively confirm the causative infectious organisms.
Although present in only 20% of the general population, the genetically encoded cell marker, HLA-DR4, occurs in more than two-thirds of Caucasian RA patients. The genetic code for this antigenic marker is found on the short arm of the sixth chromosome in humans. Patients who have the marker are more likely to develop rheumatoid arthritis than those who don’t. However, the presence of the marker does not guarantee the onset of rheumatoid arthritis. The researchers believe that the marker indicates only a genetic predisposition.
Cigarette smoking doubles the risk of developing the pathophysiology of rheumatoid arthritis. Patients who have smoked for more than 25 years have a threefold increase in the likelihood of having rheumatoid arthritis with the development of bone erosion. Tobacco use increases white blood cell counts and circulating blood levels of the antibody, rheumatoid factor. The link between smoking and RA is stronger in men than women.
Without a doubt, immune cells and cells lining the joints mediate the chronic joint inflammation characteristic of rheumatoid arthritis. White blood cells flow into the joints, causing pain, swelling, warmth and redness. The cells also release chemical mediators, including cytokines, antibodies, interleukins, and tumor necrosis factors (TNF), which promote scarring and destruction of the joint lining and cartilage. In the later stages, the bone erodes and the joint becomes deformed. Cytokines also produce the whole-body pathophysiology of rheumatoid arthritis, such as body aches, weight loss, and fever.
Protect your devices with Threat Protection by NordVPN
