Experts Review Diagnosis, Treatment of ANCA Glomerulonephritis and Vasculitis

A review about the anti-neutrophil cytoplasmic antibody (ANCA) glomerulonephritis and vasculitis outlined the best way to characterize the different kinds of ANCA-associated disease in order to provide better treatment.

The review, “ANCA Glomerulonephritis and Vasculitis,” was published in the Clinical Journal of the American Society of Nephrology.

ANCA glomerulonephritis and vasculitis are rare autoimmune diseases, meaning that the body’s own immune system injures its cells and tissues. Vasculitis is a disorder where there is destruction of blood vessels by inflammation that affects both arteries and veins. Glomerulonephritis is a kind of kidney disease caused by inflammation in the glomeruli (the small blood vessels) in the kidneys.

ANCA vasculitis usually affects people older than 50, and the different kinds are more common in different geographical areas.

In the case of ANCA-associated vasculitis, antibodies to substances inside white blood cells called neutrophils cause the disease. It is believed that the antibodies activate the neutrophils in the blood, where they cause damage to blood vessels.

The vasculitis can affect different parts of the body, sometimes causing glomerulonephritis or affecting the respiratory tract.

ANCA vasculitis is divided into several categories, based on the serotype of the autoantibodies and also on the diagnostic classification based on laboratory tests.

The serotypes are classified on the basis of which substance inside neutrophils the autoantibodies target. MPO-ANCA targets a protein called myeloperoxidase (MPO), and PR3-ANCA targets proteinase 3 (PR3), another protein.

The diagnostic classifications include three kinds of polyangiitis, which is inflammation involving multiple blood or lymph vessels (vessels that transport white blood cells throughout the body).

One kind of polyangiitis is microscopic polyangiitis (MPA), causing damage to organ systems. The areas most commonly affected by MPA include the kidneys, lung, nerves, skin, and joints.

The second kind is called granulomatosis with polyangiitis (GPA), or Wegener granulomatosis, where inflammation in tissues outside blood vessels occurs, often in the respiratory tract. The third kind is known as eosinophilic granulomatosis with polyangiitis (EGPA), or Churg-Strauss syndrome, where another type of white blood cell called an eosinophil is activated.

A fourth kind of ANCA vasculitis is renal-limited vasculitis, which affects only the kidneys.

The authors recommend using both the serotype and diagnostic classification in the management of every case of the disease.

Treatment is presently cyclophosphamide (an immune suppressant) and glucocorticoids (a class of steroid hormones), to induce remission, and most patients need low-dose therapy afterward to maintain the state of remission.

The U.S. Food and Drug Administration has approved the use of Rituxan (rituximab) for the induction of remission in ANCA disease. Clinical trials have shown that Rituxan is non-inferior compared to cyclophosphamide for this indication.

“Prompt diagnosis and rapid initiation of effective treatment are the most important factors for optimum outcome in patients with ANCA disease,” authors of this study stated.

“Current management strategies are superior to those in earlier decades because of more effective and more targeted drugs, and treatment regimens that are more personalized to the nature of the disease in individual patients. Ongoing advances in understanding ANCA disease mechanisms, and development of more effective, less toxic, and more targeted therapies, undoubtedly will lead to even better outcomes in the future,” they concluded.