Our immune system has a dark side: It’s supposed to fight off invaders to keep us healthy. But sometimes it turns traitor and attacks our own cells and tissues.What are called autoimmune diseases can affect just about every part of the body – and tens of millions of people. While most common in women, these diseases can strike anyone, adults or children, and they’re on the rise.New research is raising the prospect of treatments that might do more than tamp down symptoms. Dozens of clinical trials are testing ways to reprogram an immune system-gone-rogue, with some promising early successes against lupus, myositis and certain other illnesses. Other researchers are hunting ways to at least delay brewing autoimmune diseases, spurred by a drug that can buy some time before people show symptoms of Type 1 diabetes.AdvertisementAdvertisementAdvertisementAdvertisement“This is probably the most exciting time that we’ve ever had to be in autoimmunity,” said Dr. Amit Saxena, a rheumatologist at NYU Langone Health.Here are some things to know.What are autoimmune diseases?They’re chronic diseases that can range from mild to life-threatening, more than 100 with different names depending on how and where they do damage. Rheumatoid arthritis and psoriatic arthritis attack joints. Sjögren’s disease is known for dry eyes and mouth. Myositis and myasthenia gravis weaken muscles in different ways, the latter by attacking how nerves signal them. Lupus has widely varied symptoms including a butterfly-shaped facial rash, joint and muscle pain, fevers and damage to the kidneys, lungs and heart.AdvertisementAdvertisementAdvertisementAdvertisementThey’re also capricious: Even patients faring well for long periods can suddenly have a “flare” for no apparent reason.Why autoimmune diseases are so difficult to diagnoseMany start with vague symptoms that come and go or mimic other illnesses. Many also have overlapping symptoms – rheumatoid arthritis and Sjögren’s also can harm major organs, for example.Diagnosis can take multiple tests, including some blood tests to detect antibodies that mistakenly latch onto healthy tissu …
