Antibody Diagnostics in Autoimmune Nephropathies

Types of Autoimmune Nephropathies and Their Key Antibody Diagnostic Tests?

Autoimmune nephropathy is a collection of diseases wherein the body produces certain substances known as autoantibodies which attack and harm the cells of the kidneys in various ways. Some autoimmune nephropathic conditions include:

1. Primary Membranous Nephropathy (MN)

This condition occurs when our body’s defense system attacks the glomeruli —small blood vessels in the kidney that filter wastes from the blood. This results in the glomeruli becoming damaged and thickened causing you to lose a large amount of protein in your urine. If high levels of protein continue to be excreted, it can lead to kidney failure.

Test

- Anti PLA2R: The phospholipase A2 receptor is a major antigen. However, anti-PLA2R autoantibodies are prevalent in patients thus making it a promising serum biomarker in the diagnosis of Primary MN. It is also useful as a marker for disease treatment, prognosis, and recurrence.

- Anti THSD7A: Patients with MN have autoantibodies against THSD7A thus making this test an important diagnostic tool.

2. Lupus Nephritis

Lupus Nephritis is an autoimmune condition wherein the body’s immune system turns against the kidneys. This results in inflammation or scarring of the glomeruli. Signs of the disease include blood or excess protein in the urine, edema, weight gain, and high blood pressure.

Test

- Antinuclear Antibody (ANA) Test: This blood test looks for the presence of antinuclear antibodies in the blood. These include:
- Anti dsDNA: A high level of this in the blood strongly points towards lupus and is often significantly increased during or just before a flare-up of the condition.
- Anti Nucleosomes: This is detected in patients with lupus and its presence is associated with disease activity.

3. Goodpasture’s Syndrome

An uncommon autoimmune disease that affects both the kidneys and the lungs, it causes the immune system to attack tissues in the lungs and kidneys. If left untreated, it causes kidney failure, lung damage, and even death. Symptoms include coughing up blood and trouble breathing.

Test

- Anti GBM Test: Glomerular Basement membrane (GBM) is a part of the kidneys that helps filter excess waste and fluid from the blood. Anti-GBM antibodies are antibodies against this which lead to kidney damage.

4. Renal Vasculitis

This is a rapidly progressive disease that causes white blood cells to attack the glomeruli. The result is leaked blood and protein into the urine, which over time leads to loss of kidney function or even kidney failure in severe cases.

Test

- ANCA Test: Anti-neutrophil cytoplasmic antibodies cause white blood cells to attack the kidneys. These tests detect the presence of ANCA antibodies in the blood. These include:
- Anti PR3: An ELISA-based test used to detect the presence of IgG antibodies against proteinase 3 (PR3) in the blood.
- Anti Myeloperoxidase (MPO): The presence of these antibodies can help determine which type of vasculitis you have.

Conclusion

Autoimmune conditions such as the various types of nephropathies may worry you but remember that the first step towards treatment and management of the condition is a proper diagnosis. That’s where we at Metropolis come in. Please do not hesitate to connect with us or with your healthcare provider for a greater understanding of the above-mentioned nephropathies and diagnostic tests.