Autoimmune disease is a condition in which the body’s immune system mistakes its own healthy tissues as foreign and attacks them instead of defending. It could be within the body of the individual or host, termed self-antigen, or from outside, called foreign antigen like the virus, bacteria, toxin, etc. The body's immune response can be categorized into 2 types: innate and adaptive. Innate response is rapid and transient, whereas adaptive, on the other hand, is slow and may take a longer time to respond, but the effect is generally long lasting as it carries memory with it.

Symptoms of autoimmune illnesses can be mild or severe and episodic. There are more than 100 autoimmune disorders that we are aware of, and these affect almost any organ in the body such as the muscle, joint, skin, abdominal organs, digestive, nervous system, kidneys, blood vessels, and salivary glands. Some of the common autoimmune diseases that are quite familiar to the public are Type 1 Diabetes Mellitus, Vitiligo, Psoriasis, Myositis, Multiple Sclerosis, Vasculitis, etc.
Salient characteristics of autoimmune diseases are as follows:

• Autoimmune diseases are more common among females than males. Many of these illnesses have a genetic predisposition, meaning they run in the family.
• There is a strong correlation between smoking and autoimmune diseases, with smokers having a higher likelihood to develop the disease than non-smokers.
• They are also commonly triggered by infections, dietary factors, and toxins.
• Multiple autoimmune diseases can be found in a single individual. This is because once they are exposed to one autoimmune disorder, their chances of developing many such conditions are relatively higher.
• Autoimmune diseases are mostly chronic and irreversible, wherein remission and relapses are the rule.

Kidney-related autoimmune diseases:
In cases of kidney related autoimmune diseases, the immune system targets the kidneys leading to inflammation, damage and kidney failure in some cases. Lupus Nephritis , Rheumatoid Arthritis, IgA Nephropathy , Sjögren’s Syndrome, Anti-GBM and Good Pasteur’s Disease are a few common autoimmune diseases that affect kidneys.

Lupus Nephritis is very common amongst females, a multi-system disease with different classes based on the kidney biopsy. Early detection & treatment with immunosuppressives is the key to controlling the disease. Similarly, IgA Nephropathy also commonly affects younger individuals, causing haematuria (blood in the urine), proteinuria (blood in the urine), and renal insufficiency (kidney failure).

Rheumatoid Arthritis affects mainly the smaller joints of the body and the kidneys, causing inflammation and damage. Anti-GBM and Good Pasteur’s disease is a dreaded illness requiring corticosteroids, cyclophosphamide, and plasmapheresis to circumvent the disease. Although Sjögren’s Syndrome primarily affects glands that produce tears/saliva, it can also damage the kidneys, leading to Interstitial Nephritis (inflammation of the renal interstitium – the area between the kidney tubules).

How to diagnose autoimmune diseases?
Diagnosing autoimmune diseases can be challenging, but it generally involves:

• Good clinical history, family history, and physical examination
• Tests - Urine for proteinuria, blood cells, CBC, Renal function tests
• Specific tests for individual disorder like ANA (Antinuclear Antibodies), Anti-dsDna (Anti-double-stranded DNA), Anti-GBM antibody (Anti-glomerular basement membrane antibody), ANCA (Antineutrophil cytoplasmic antibodies), RNP (Ribonucleoprotein antibodies), etc.
• X-ray of the chest, ultrasound, CT, and MRI
• Biopsy of the kidneys and other organs

Treatment:
Treatment for these autoimmune diseases depends on the type of autoimmune disease one is dealing with. Immunosuppressants and Monoclonal antibodies can decrease activity of the immune system or block inflammation. Dialysis and kidney transplantation may be required for autoimmune diseases causing kidney failure. Palliative therapy in the form of meditation and yogic treatment can help calm the mind, body, and immune system.
This World Kidney Day, let’s prioritize our kidney health and be informed of the risks and preventive measures for autoimmune diseases causing kidney dysfunction.

Dr. G K Prakash, Consultant – Nephrology, Manipal Hospital Malleshwaram and Millers Road.