Sjogren syndrome

Definitions & Key takeaways

Sjogren's syndrome is an autoimmune disease in which the body's immune cells attack various moisture-producing exocrine glands, which normally pour their secretions into various ducts in the body, such as the salivary and the lacrimal glands. This results in the development of a dry mouth and dry eyes. Other symptoms can include dry skin, a chronic cough, vaginal dryness, numbness in the arms and legs, feeling tired, and muscle and joint pains. Treatment of Sjogren's syndrome typically involves medications to suppress the immune response, like corticosteroids; and also medications that increase the exocrine secretions like pilocarpine.

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Introduction0:00–0:26

Sjogren's syndrome named after Doctor Henrik Sjogren who first identified it is a common autoimmune disorder. Typically happening in women in Sjogren's syndrome.
The body's immune cells go rogue and start attacking various exocrine glands which are glands that pour their secretions into a duct.
Most commonly the salivary glands and the lacri mole or tear glands. Normally, the cells of the immune system are ready to spot and destroy anything foreign that could cause the body harm immune cells called antigen presenting cells which include macrophages and dendritic cells, latch onto pathogens and engulf them, literally swallowing them up pieces of the pathogen called antigens are then presented on a major histocompatibility complex class two molecule or MHC class two molecule which is like a serving platter for antigens.

Physiology0:26–1:14

An antigen presenting cell then searches for at cell that can bind to the antigen once found, binding to the antigen helps activate this T cell and then releases proinflammatory cytokines or signaling molecules that recruit more immune cells ultimately leading to inflammation.

Causes1:14–1:57

The exact cause for Sjogren's syndrome is unknown, but it seems to be related to both genetic and environmental factors.
Genetic factors include genes which code for specific types of MHC class two molecules called human leukocyte antigen or HLA A genes specifically HLA Drw 52 HLA D QA one or HLA AD Q B1.
Environmental factors include an infection of exocrine glands, like the salivary and lacrimal glands. Infections can damage the cells of the salivary gland and expose their cell components including their DNA, RNA and histones to circulating immune cells.

Pathology1:57–3:17

These cell components get picked up by antigen presenting cells and presented to T cells in individuals with Sjogren's syndrome.
At cell gets inappropriately activated by these nuclear components and considers them to be foreign nuclear antigens. The T cells then activate B cells.
We start producing anti nuclear antibodies or A S which are antibodies against the nuclear antigens. Two types of A, a formed in Sjogren's syndrome are anti SSA and anti SSB antibodies which are formed against the ribonucleoproteins.
SSA and SSB. Then both T cells and antibodies enter the circulation and reach the exocrine glands where the T cells secrete cytokines to recruit more immune cells and promote inflammation of the exocrine gland tissue.
The cytokines also activated fibroblasts in the tissue which then produce fibrous tissue that replaces the damaged tissue.
The end result is a loss of secretory cells in the glands. Sjogren's syndrome can be primary and happen alone and in that situation, it's called Sicca syndrome.
Alternatively, it can be secondary which is when it happens along with other autoimmune diseases like rheumatoid arthritis, symptoms of Sjogren's Syndrome usually present in middle aged women and are due to dryness of various body surfaces.

Symptoms3:17–4:20

When the lacrimal gland is involved, it leads to Caro conjunctivitis, which is the inflammation and ulceration of the cornea and conjunctiva.
This causes dryness of the eyes leading to blurring of vision, itching, redness and burning of the eyes. When the salivary glands are involved, it leads to xerostomia or dryness of the mouth as well as difficulty tasting and swallowing and cracks and fissures in the mouth.
In the nose and respiratory passages, it causes ulceration and perforation of the nasal septum and can lead to crusting and bleeding.
When it affects the larynx, it can lead to difficulty speaking in some people. There might also be dryness of the skin and vagina.
There's also swelling of the glands which can compress nearby structures like nerves and cause pain. Finally, the dryness of epithelial linings can also make infections more likely.
Diagnosis of Sjogren's syndrome is based on a decrease in exocrine gland secretion. For example, sialometry can be done to measure the saliva flow.

Diagnosis4:20–4:50

Blood tests often show the presence of anti SS A and anti SS B antibodies. A confirmatory test is a lip biopsy to examine the minor salivary glands, especially CD four positive T cells, plasma cells and macrophages and thickening of the inner duct wall.
Treatment of Sjogren's syndrome typically involves medications to suppress the immune response like corticosteroids and also medications that increase the exocrine secretions like pilocarpine.

Treatment4:50–5:03

All right. As a quick recap.

Review5:03–5:26

Sjogren's syndrome is caused by autoimmune destruction of the exocrine glands. Most commonly the salivary and lacrimal glands often following an infection.
Anti nuclear antibodies, typically anti SS A and anti SS B antibodies cause destruction of the secretory cells in the exocrine glands resulting in dry eyes and mouth.