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What happens when the things that are supposed to keep us safe turn against us? In fiction, this is usually posed as some big, world-ending problem like artificial intelligence going off the rails and killing everybody. In nonfiction, this question is hashed out in the world of autoimmune diseases. 

Systemic Lupus Erythematosus (SLE) is an autoimmune disease that typifies an entire cluster of autoimmune diseases , known as “lupus-associated”. These include rheumatoid arthritis, systemic sclerosis (scleroderma), Sjogren’s syndrome, and more. These diseases tend to spread though different parts of the body, which is why many have “systemic” in the name. 

Systemic lupus erythematosus is a chronic and progressive autoimmune disease. Chronic indicates that it is long-lasting, and progressive means that the disease can change over time, usually by getting stronger and more severe. It is much more prevalent in racial and ethnic minorities, and 90% of sufferers are women. These statistics immediately give us clues as to the nature of SLE and autoimmune diseases: they have a genetic component. People from different parts of the world have different packages of genes, but why are women so susceptible? 

Genes are part of our DNA, the code that describes what we are. Specifically, they are sections of code that describe how to build a protein. Each gene has instructions for a single protein, and changes to the genetic code can result in changes to the protein that it’s supposed to build. Genes aren’t randomly distributed in the DNA code; they are located on chromosomes. We have 23 chromosomes that we get from our mother and 23 from our father. Most are the same size, but the X and Y sex chromosomes look different. The X chromosome, attributed to females, contains 800-900 genes while the Y chromosome, attributed to males, contains only 50-60 genes! It is thought that a genetic component of autoimmune diseases may be found on the X chromosome. 

The immune system is made of cells that have specific proteins they use to identify invaders, send alert signals, and attack. A huge class of signaling molecules is called hormones. Many of these are proteins. One class of immune hormone proteins is interleukins. When there are too many of these, they are in the wrong place, or they have changed in some way the immune system can go haywire and attack healthy cells. 

Autoimmune diseases like SLE are complex. The immune system gets out of whack due to multiple conditions acting together. Affected people have a genetic predisposition: their DNA has code that makes it likely to produce dangerous levels or types of interleukins. This isn’t a foregone conclusion, however. An environmental stimulus is needed to start the autoimmune process. This can be airborne particles like silica or cigarette smoke, drugs including contraceptives, viruses, and even sunlight! When the genetic primer is lit, the immune system misidentifies what is good and bad and can explode on healthy cells.

Like many autoimmune diseases, SLE has a cycle of remission and relapse; people have symptom-free periods, and periods of increased symptom activity. Symptoms may be low on the disease scale, including pain, fatigue, and a rash on the face. This rash may be exacerbated by UV light, appearing on the nose and cheeks where we get sun. This takes on the classic “butterfly rash” shape associated with SLE. Higher on the disease scale is damage to organs like the kidneys, heart, lungs, bloodstream, gut, and nervous system. When it is widespread it can also cause skin and joint disease, including arthritis. Severe cases can lead to hospitalization and death. 

So what can we do about autoimmune diseases like SLE? Each patient is different, each disease is different, and doctors have to balance the effects of medications against side effects. In general, the most obvious preventative step for autoimmune diseases is something that calms the immune system down. Antimalarials like hydroxychloroquine decrease immune activity and are often a preventative step. During flare-ups, a targeted anti-inflammatory like a glucocorticoid may be used. If these fail, doctors may prescribe immunosuppressant drugs or monoclonal antibodies. Specific organ maintenance, like treating liver and kidney problems can help alleviate damage, and doctors can also recommend procedures that work directly on our bloodstream. The future may hold promise for new medications that target specific parts of the autoimmune disease pathway. Keep your eyes open for new clinical trials aimed at helping those with autoimmune diseases like SLE.

Staff Writer / Editor Benton Lowey-Ball, BS, BFA

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References:

Ameer, M. A., Chaudhry, H., Mushtaq, J., Khan, O. S., Babar, M., Hashim, T., … & Khan, O. S. (2022). An overview of systemic lupus erythematosus (SLE) pathogenesis, classification, and management. Cureus, 14(10). https://doi.org/10.7759/cureus.30330

Angum, F., Khan, T., Kaler, J., Siddiqui, L., & Hussain, A. (2020). The prevalence of autoimmune disorders in women: a narrative review. Cureus, 12(5). https://doi.org/10.7759/cureus.8094

Barber, M. R., Drenkard, C., Falasinnu, T., Hoi, A., Mak, A., Kow, N. Y., … & Ramsey-Goldman, R. (2021). Global epidemiology of systemic lupus erythematosus. Nature Reviews Rheumatology, 17(9), 515-532. https://doi.org/10.1038/s41584-021-00668-1

Mackay, I. R. (2009). Clustering and commonalities among autoimmune diseases. Journal of autoimmunity, 33(3-4), 170-177. https://doi.org/10.1016/j.jaut.2009.09.006