Autoimmune disease terms and medical terminology explained in plain language
(aw-toh-ih-MYOON dih-ZEEZ)
A condition in which the immune system mistakenly attacks the body's own healthy cells and tissues, treating them as foreign invaders. There are over 100 different autoimmune diseases affecting virtually every part of the body, from joints (rheumatoid arthritis) to organs (Hashimoto's thyroiditis affecting the thyroid) to multiple body systems (lupus).
(AN-tee-NOO-klee-ar AN-tih-bod-ee)
A blood test that detects antibodies targeting the nucleus of cells. A positive ANA test can indicate an autoimmune disease, but is not diagnostic by itself—many healthy people test positive. Common in lupus, Sjögren's syndrome, and scleroderma. Results are reported with a pattern (homogeneous, speckled, etc.) and titer (concentration level).
(AN-tih-bod-ee)
Proteins produced by B cells (a type of white blood cell) that identify and neutralize foreign substances like bacteria and viruses. In autoimmune diseases, the body produces autoantibodies that mistakenly target the body's own tissues. Examples include anti-CCP in rheumatoid arthritis and anti-dsDNA in lupus.
(ar-THRY-tis)
Inflammation of one or more joints, causing pain, swelling, stiffness, and reduced range of motion. In autoimmune diseases like rheumatoid arthritis and psoriatic arthritis, the immune system attacks the joint lining (synovium), potentially causing permanent damage if untreated. Different from osteoarthritis, which is wear-and-tear related.
(aw-toh-AN-tih-bod-ee)
An antibody that mistakenly targets and attacks the body's own proteins, cells, or tissues. Different autoimmune diseases produce different autoantibodies: RF in rheumatoid arthritis, anti-TPO in Hashimoto's, anti-dsDNA in lupus. Testing for specific autoantibodies helps diagnose and differentiate between autoimmune conditions.
(BEE sell)
A type of white blood cell that produces antibodies to fight infections. In autoimmune diseases, B cells can produce autoantibodies that attack the body's own tissues. Many biologic treatments target B cells, including rituximab and newer CAR-T therapies that "reprogram" or eliminate disease-causing B cells.
(by-oh-LOJ-ik)
Medications derived from living organisms that target specific components of the immune system. Unlike traditional drugs made from chemicals, biologics are proteins that block particular inflammatory pathways. Examples include TNF inhibitors (Humira, Enbrel), IL-6 inhibitors (Actemra), and B cell depleters (Rituxan). Administered by injection or infusion.
(BY-oh-mar-ker)
A measurable indicator of disease presence, severity, or response to treatment. In autoimmune disease, biomarkers include antibody levels (ANA, RF), inflammation markers (CRP, ESR), and organ function tests. Tracking biomarkers helps monitor disease activity and treatment effectiveness over time.
(car-TEE sell THER-uh-pee)
Chimeric Antigen Receptor T-cell therapy—a breakthrough treatment where a patient's T cells are genetically modified to target and eliminate disease-causing B cells. Originally developed for cancer, now showing remarkable success in severe autoimmune diseases like lupus, achieving 100% remission in early trials. Involves collecting cells, modifying them in a lab, and reinfusing them.
(SEE ree-AK-tiv PRO-teen)
A blood test measuring inflammation levels in the body. CRP is produced by the liver in response to inflammation. Elevated levels indicate active inflammation but don't specify the cause. Used alongside other tests to monitor autoimmune disease activity and treatment response. High-sensitivity CRP (hs-CRP) can detect lower levels of inflammation.
(KROHNZ dih-ZEEZ)
An inflammatory bowel disease (IBD) causing chronic inflammation of the digestive tract, most commonly affecting the small intestine and beginning of the colon. Can affect any part from mouth to anus. Symptoms include severe diarrhea, abdominal pain, fatigue, weight loss, and malnutrition. Causes transmural inflammation (through all layers of bowel wall).
(SY-toh-kine)
Small proteins that act as messengers between cells in the immune system, regulating inflammation and immune responses. In autoimmune diseases, certain cytokines like TNF-alpha, IL-6, and IL-17 become overactive, driving inflammation and tissue damage. Many biologic treatments work by blocking specific cytokines.
(DEE-mard)
Medications that slow disease progression and prevent permanent damage in autoimmune diseases, particularly rheumatoid arthritis. Include conventional DMARDs (methotrexate, hydroxychloroquine) and biologic DMARDs (targeted therapies). Work by suppressing overactive immune responses. Take weeks to months to show effect, unlike pain relievers that work immediately.
(dis-by-OH-sis)
An imbalance in the gut microbiome (the community of bacteria and other microorganisms in the digestive system). Research suggests dysbiosis may contribute to autoimmune disease development and flares by affecting immune regulation. Improving gut health through diet, probiotics, and stress management may help some patients.
(ee-RITH-roh-site sed-ih-men-TAY-shun rate)
A blood test measuring how quickly red blood cells settle at the bottom of a test tube. Elevated ESR indicates inflammation in the body. Used alongside CRP to monitor autoimmune disease activity. Sometimes called "sed rate." Less specific than CRP but useful for tracking disease trends over time.
(FLAIR)
A period of increased disease activity and worsening symptoms. During a flare, inflammation intensifies, causing more pain, fatigue, and other symptoms. Can be triggered by stress, illness, medication changes, or occur without obvious cause. Managing flares often requires temporary medication adjustments and increased self-care.
(HYOO-man LOO-koh-site AN-tih-jen)
Proteins on cell surfaces that help the immune system distinguish between "self" and "foreign." Certain HLA variants increase autoimmune disease risk: HLA-B27 in ankylosing spondylitis, HLA-DR4 in rheumatoid arthritis, HLA-DQ2/DQ8 in celiac disease. Having risk variants doesn't guarantee disease development—environmental factors also play a role.
(hah-shee-MOH-tohz thy-roy-DY-tis)
An autoimmune disease where the immune system attacks the thyroid gland, gradually destroying its ability to produce hormones. Most common cause of hypothyroidism (underactive thyroid). Symptoms include fatigue, weight gain, cold sensitivity, depression, hair loss, and dry skin. Treated with thyroid hormone replacement (levothyroxine).
(im-yoo-noh-suh-PRES-ant)
Medications that suppress or reduce the strength of the immune system. Used to prevent the immune system from attacking the body in autoimmune diseases. Include corticosteroids, methotrexate, azathioprine, and biologics. While reducing harmful autoimmune activity, they also increase infection risk, requiring careful monitoring and preventive measures.
(in-fluh-MAY-shun)
The body's natural immune response to injury or infection, characterized by redness, heat, swelling, and pain. In autoimmune diseases, chronic inflammation occurs when the immune system continuously attacks healthy tissues. Over time, persistent inflammation can cause permanent tissue and organ damage, making early treatment crucial.
(im-yoo-noh-THER-uh-pee)
Treatment that modifies or harnesses the immune system. In autoimmune disease, includes biologics that block specific immune pathways, CAR-T therapy that reprograms immune cells, and stem cell transplants that "reset" the immune system. Represents a shift from broadly suppressing immunity to precisely targeting disease mechanisms.
(jak in-HIB-ih-tor)
Janus Kinase inhibitors—oral medications that block enzymes involved in inflammatory signaling pathways. Examples include tofacitinib (Xeljanz) and baricitinib (Olumiant). Offer an alternative to injectable biologics with similar efficacy. Used for rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. Require monitoring for side effects including increased infection risk.
(LOO-pus / sis-TEM-ik LOO-pus er-ih-them-uh-TOH-sus)
A chronic autoimmune disease that can affect multiple organs including skin, joints, kidneys, brain, heart, and lungs. Characterized by periods of flares and remission. Symptoms include joint pain, skin rashes (butterfly rash across cheeks), extreme fatigue, fever, and organ inflammation. More common in women, particularly those of African, Hispanic, and Asian descent. No cure, but treatable.
(LIM-foh-site)
A type of white blood cell crucial to immune function. Main types include B cells (produce antibodies), T cells (kill infected cells and regulate immune responses), and NK (natural killer) cells. In autoimmune diseases, lymphocytes become dysregulated and attack healthy tissues. Many treatments target specific lymphocyte populations.
(meth-oh-TREK-sate)
A first-line DMARD medication for many autoimmune diseases, particularly rheumatoid arthritis. Originally developed as chemotherapy but used at much lower doses for autoimmune conditions. Taken weekly (not daily). Requires folic acid supplementation and regular blood monitoring. Highly effective at reducing inflammation and preventing joint damage when used early.
(MUL-tih-pul skleh-ROH-sis)
A chronic autoimmune disease affecting the central nervous system (brain and spinal cord). The immune system attacks myelin, the protective covering of nerve fibers, disrupting communication between the brain and body. Symptoms vary widely: vision problems, muscle weakness, coordination difficulties, cognitive changes, and fatigue. Types include relapsing-remitting, primary progressive, and secondary progressive MS.
(prih-SIZH-un MED-ih-sin)
Healthcare approach that customizes treatment based on individual genetic makeup, biomarkers, lifestyle, and environment. In autoimmune disease, involves using genetic testing, biomarker panels, and AI analysis to predict which treatments will work best for each patient, moving away from trial-and-error approaches toward targeted, personalized therapy.
(suh-RY-uh-sis)
An autoimmune skin condition causing rapid skin cell buildup, resulting in thick, scaly patches (plaques) that are often itchy and painful. Affects 7.5 million Americans. About 30% develop psoriatic arthritis. Triggered by immune system overactivity causing excessive skin cell production. Treated with topicals, phototherapy, systemic medications, and biologics.
(rih-MISH-un)
A period when disease activity is minimal or absent, and symptoms are significantly reduced or eliminated. Can be spontaneous or achieved through treatment. In autoimmune disease, remission doesn't mean cure—the condition can reactivate. The goal of treatment is achieving and maintaining remission. May be partial (some improvement) or complete (no detectable disease activity).
(ROO-muh-toyd ar-THRY-tis)
The most common systemic autoimmune disease, affecting 1.3 million Americans. Immune system attacks joint linings (synovium), causing painful swelling that can erode bone and deform joints. Typically affects hands, wrists, and feet symmetrically. Can also affect heart, lungs, and eyes. Early aggressive treatment with DMARDs can prevent permanent damage and achieve remission.
(ROO-muh-toyd FAK-tor)
An autoantibody found in about 80% of people with rheumatoid arthritis. Blood test measuring RF levels helps diagnose RA, though positive results can occur in other conditions and some healthy people. Often tested alongside anti-CCP antibodies for more accurate diagnosis. Higher RF levels may indicate more severe disease.
(SHOW-grenz SIN-drohm)
An autoimmune disease primarily affecting moisture-producing glands, causing severe dry eyes and dry mouth. Can also cause joint pain, fatigue, and affect kidneys, lungs, and nervous system. Affects 4 million Americans, 90% women. Can occur alone (primary) or with other autoimmune diseases (secondary). Managed with artificial tears, saliva substitutes, and immunosuppressants for systemic symptoms.
(stem sell TRANS-plant)
Hematopoietic Stem Cell Transplantation—a procedure that "reboots" the immune system by replacing diseased immune cells with healthy stem cells. Involves harvesting patient's stem cells, eliminating existing immune cells with chemotherapy, then reinfusing stem cells to rebuild a healthier immune system. Reserved for severe, treatment-resistant autoimmune diseases due to risks and intensity.
(sis-TEM-ik)
Affecting the entire body or multiple organ systems, rather than a single location. Systemic autoimmune diseases like lupus, Sjögren's, and rheumatoid arthritis can impact multiple organs simultaneously. Symptoms may include widespread fatigue, fever, weight loss, and malaise alongside organ-specific manifestations.
(TEE sell)
A type of white blood cell critical to immune function. Different T cells have different roles: helper T cells coordinate immune responses, cytotoxic T cells kill infected cells, and regulatory T cells prevent overreaction. In autoimmune diseases, T cell regulation fails, leading to attacks on healthy tissue. Some treatments target T cells; CAR-T therapy reprograms them.
(TOO-mor neh-KROH-sis FAK-tor)
A cytokine (inflammatory protein) that plays a key role in systemic inflammation. Overproduction causes chronic inflammation in autoimmune diseases. TNF inhibitors (biologics like Humira, Enbrel, Remicade) block this protein, reducing inflammation and slowing disease progression. Among the most successful and widely used biologic treatments for autoimmune conditions.
(type one dy-uh-BEE-teez)
An autoimmune disease where the immune system destroys insulin-producing beta cells in the pancreas. Without insulin, the body cannot regulate blood sugar, leading to dangerously high levels. Requires lifelong insulin therapy via injections or pump. Typically diagnosed in childhood/adolescence but can occur at any age. Different from type 2 diabetes, which is not autoimmune.
(UL-sir-uh-tiv koh-LY-tis)
An inflammatory bowel disease (IBD) causing chronic inflammation and ulcers in the colon and rectum. Unlike Crohn's, affects only the colon and involves continuous inflammation of the innermost lining. Symptoms include bloody diarrhea, abdominal pain, urgency, and fatigue. Increases colon cancer risk with long-term disease. Treated with anti-inflammatory medications, immunosuppressants, and biologics.
(vas-kyoo-LY-tis)
Inflammation of blood vessels that can restrict blood flow, causing organ and tissue damage. Can affect vessels of any size in any organ. Types include giant cell arteritis, Takayasu's arteritis, and ANCA-associated vasculitis. Symptoms vary by affected vessels but may include fever, fatigue, weight loss, and organ-specific problems. Often requires aggressive immunosuppression.