Anti-neutrophil cytoplasmic antibody

Anti-Neutrophil Cytoplasmic Antibody (ANCA)

Micrograph showing ANCA staining in neutrophils.

Immunofluorescence pattern produced by binding of ANCA from a patient with Wegener's Granulomatosis to ethanol-fixed neutrophils

Anti-neutrophil cytoplasmic antibodies (ANCA) are specific types of antibodies directed against certain proteins found within neutrophils, the most common type of white blood cell. Their presence is strongly associated with certain forms of autoimmune vasculitis, where the body's immune system mistakenly attacks its blood vessels.

Overview

ANCAs have become increasingly recognized for their role in the pathogenesis and diagnosis of a subset of vasculitides known as ANCA-associated vasculitides (AAV). These conditions lead to inflammation and damage to blood vessels, primarily affecting small-sized vessels.

Pathogenesis

Neutrophils, which play a crucial role in the body's defense against infections, contain various proteins. In individuals with ANCA, the immune system produces antibodies against these proteins, leading to neutrophil activation and subsequent vessel inflammation, resulting in vasculitis.

Types of ANCA

There are mainly two types of ANCAs based on their staining patterns when observed under a microscope:

• c-ANCA (cytoplasmic ANCA): Primarily targets proteinase 3 (PR3). Commonly associated with granulomatosis with polyangiitis (GPA).
• p-ANCA (perinuclear ANCA): Targets myeloperoxidase (MPO). Often linked with microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA).

Clinical Implications

ANCA testing is instrumental in diagnosing, classifying, and monitoring disease activity in patients with suspected ANCA-associated vasculitis. While ANCAs are valuable diagnostic markers, their levels do not always correlate with disease severity.

Diseases Associated with ANCA

• Granulomatosis with polyangiitis (GPA)
• Microscopic polyangiitis (MPA)
• Eosinophilic granulomatosis with polyangiitis (EGPA)

Treatment

Management of ANCA-associated vasculitis generally involves:

• Immunosuppressive therapies to reduce inflammation and halt the immune system's abnormal response.
• Regular monitoring for disease activity and potential relapses.
• Addressing and managing complications arising from organ involvement.

Immunofluorescence pattern of PR3 antibodies

Other names

ANCA antibodies, cANCA pANCA, cytoplasmic neutrophil antibodies, serum, anticytoplasmic autoantibodies

Clinical use

ANCA test is used to diagnose autoimmune vasculitis.

Types of autoimmune vasculitis

Types of autoimmune vasculitis include:

1. Granulomatosis with polyangiitis (GPA), )Wegener's disease) affecting the lungs, kidneys, and sinuses.
2. Microscopic polyangiitis (MPA) affecting lungs, kidneys, nervous system, and skin.
3. Eosinophilic granulomatosis with polyangiitis (EGPA), (Churg-Strauss syndrome) affects skin and lungs. It often causes asthma.
4. Polyarteritis nodosa (PAN) affecting the heart, kidneys, skin, and central nervous system.

Symptoms

Vasculitis

Wegener's Granulomatosis - Vasculitis

• Fever
• Fatigue
• Weight loss
• Muscle and/or joint aches
• Eyes
• Redness
• Blurred vision
• Loss of vision
• Ears
• Ringing in the ears (tinnitus)
• Hearing loss
• Sinuses
• Sinus pain
• Runny nose
• Nose bleeds
• Skin
• Rashes
• Sores or ulcers, a type of deep sore that's slow to heal and/or keeps coming back
• Lungs
• Cough
• Trouble breathing
• Chest pain
• Kidneys
• Blood in the urine
• Foamy urine, which is caused by protein in the urine
• Nervous system
• Numbness and tingling in different parts of the body

Test results

If your ANCA is negative, it means your symptoms are probably not due to autoimmune vasculitis.

If you test positive for ANCA, it may indicate autoimmune vasculitis.

The test can also show which ANCA, either cANCAs or pANCAs were found which can help determine which type of vasculitis you have.

See Also

• Vasculitis
• Neutrophils
• Autoimmune diseases

References

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