Amyloidosis is not an autoimmune disorder. However, it is related to several autoimmune conditions. Sometimes, amyloidosis and its related conditions can look similar and cause similar symptoms. Also, autoimmune disorders can sometimes cause amyloidosis.

Autoimmune Disorders: An Overview

There are many kinds of autoimmune disorders. These conditions develop when the immune system stops functioning correctly.

The Immune System

The immune system is the part of the body that fights infection. It recognizes and kills viruses, bacteria, and other germs that enter the body. After it fights an infection, the immune system “remembers” the germ. If the body is exposed to the germ again, the immune system will gear up and prevent it from infecting the body’s cells.

The immune system is made up of many different cells, tissues, and organs. For example, the skin is a part of the immune system. It keeps bacteria and viruses from getting in the body. Lymphocytes (a type of white blood cell) are immune system cells. Each type of lymphocyte has a different role. They may recognize germs, activate the immune system, or make antibodies (proteins that kill germs). Lymphocytes are made in the bone marrow (tissue inside of certain bones). Many other tissues and organs — including the thymus, lymph nodes, and spleen — also play a role in protecting the body from infection.

Many types of diseases can develop in the immune system. These conditions fall into a few categories:

• Primary immune deficiency — People are born with an immune system that doesn’t effectively fight off infection.
• Acquired immune deficiency — People develop a disease that makes the immune system weaker.
• Allergies — The immune system is overactive.
• Autoimmune disorder — The immune system attacks organs or parts of the body, rather than attacking germs.

What Are Autoimmune Disorders?

Usually, the immune system only attacks substances that are foreign (come from outside the body). However, in people with an autoimmune disorder, the immune system attacks everything. It can’t tell the difference between germs and the healthy cells of the body. Autoimmune disorders damage the body’s normal tissue and change the way organs work.

More than 23.5 million Americans have autoimmune disorders. According to the U.S. National Library of Medicine, "Women — particularly African American, Hispanic American, and Native American women — have a higher risk for some autoimmune diseases."

There are more than 80 different autoimmune disorders. They include conditions such as rheumatoid arthritis, psoriasis, lupus, and Hashimoto’s thyroiditis. They can also vary in severity. Some, such as vitiligo, cause only cosmetic changes to the body. Others, such as autoimmune vasculitis, can be life-threatening.

Autoimmune disorders can cause a variety of symptoms depending on the type of autoimmune disease and on the affected location within the body. Many autoimmune disorders lead to similar symptoms, including:

• Tiredness
• Skin changes or a rash
• Fever
• Pain or swelling in the joints
• Digestive issues

Many autoimmune disorders come and go, or wax and wane. They may go into remission, where disease signs and symptoms disappear. Then, the disease may flare up and cause worsening symptoms.

Causes of Autoimmune Disorders vs. Amyloidosis

Autoimmune disorders and amyloidosis generally arise in different ways. Also, there are several types of amyloidosis, and each type has its own cause.

Doctors don’t know exactly what causes autoimmune disorders. However, they have a few theories:

• The body may start accidentally fighting normal tissue when it tries to attack germs. Some autoimmune disorders, such as psoriasis, often develop after an infection.
• Injuries may expose certain parts of the body to the immune system. For example, after an injury of the tendon (a ligament that connects muscles to bones), the immune system may attack the tendon and make joints inflamed.
• Certain genes may boost a person’s chances of developing autoimmune disorders, and some of these conditions run in families.
• High levels of hormones may increase risk of autoimmune disorders. This may be why women develop autoimmune conditions at higher rates than men.

Amyloidosis, however, is a rare disease caused by abnormal proteins. It develops when the body makes high levels of the protein amyloid that don’t fold into the correct shape. The misfolded proteins cluster together, forming amyloid deposits or amyloid fibrils that build up within organs and tissues. Doctors don’t always know why the body produces these proteins.

Amyloid Light-Chain Amyloidosis and Autoimmune Disorders

One type of amyloidosis, amyloid light-chain (AL) amyloidosis, has some links to autoimmune disorders. This form of amyloidosis also goes by "primary amyloidosis." AL amyloidosis is caused by abnormal plasma cells. Plasma cells are a part of the immune system and are responsible for making antibodies. When plasma cells become abnormal, they make high levels of antibody pieces called immunoglobulin light-chain proteins. These abnormal proteins then form amyloid deposits.

Although AL amyloidosis is caused by a type of immune cell, it is not an autoimmune disorder. Both conditions can cause organ or tissue damage, but they do so in different ways. In autoimmune disorders, the immune system causes damage by attacking specific targets, such as joints or the skin. In AL amyloidosis, amyloid proteins cause damage when they nonspecifically build up inside organs throughout the body. Other types of amyloidosis, such as hereditary amyloidosis and wild-type amyloidosis, also lead to abnormal proteins building up in organs.

Amyloidosis and autoimmune disorders can sometimes lead to similar symptoms, despite being different diseases. For example, they can both lead to carpal tunnel syndrome, dry eyes, and nail changes. Both types of conditions can also cause joint pain or stiffness.

Autoimmune Disorders Can Cause AA Amyloidosis

AA amyloidosis, or secondary amyloidosis, develops as a result of another underlying disease. Chronic infections, autoimmune diseases, and other disorders that cause inflammation can all lead to AA amyloidosis. Inflammation can make the liver produce an amyloid protein, which may form amyloid deposits in different tissues.

About half of people with AA amyloidosis have rheumatoid arthritis, an autoimmune disorder. Other conditions that can cause this form of amyloidosis include:

• Other autoimmune disorders such as juvenile arthritis, psoriatic arthritis, and ankylosing spondylitis
• Ongoing infections, including tuberculosis or osteomyelitis
• Gastrointestinal diseases that cause inflammation, such as Crohn’s disease and ulcerative colitis
• Some hereditary conditions, including familial Mediterranean fever
• Cancers such as renal cell carcinoma, Castleman disease, or Hodgkin lymphoma

Less than 5 percent of people with inflammation-causing diseases develop AA amyloidosis. If you have an autoimmune disorder or a chronic infection, you may want to watch out for amyloidosis symptoms. AA amyloidosis may lead to:

• Symptoms of kidney disease, such as swelling in the legs and ankles
• High cholesterol levels
• Digestive symptoms like constipation or diarrhea
• A drop in blood pressure when you first stand up, which may make you feel dizzy or faint
• Irregular heart rhythms

If you have an autoimmune disorder, talk to your doctor about your risk of developing amyloidosis. Your doctor may be able to help you better understand what to watch out for.

Talk With Others Who Understand

MyAmyloidosisTeam is the social network for people with amyloidosis and their loved ones. On MyAmyloidosisTeam, members come together to ask questions, give advice, and share their stories with others who understand life with amyloidosis.

Are you living with amyloidosis? Do you have an autoimmune disorder? Share your experiences in the comments below, or start a conversation by posting on MyAmyloidosisTeam.