What is IgA nephropathy?

IgA nephropathy is a chronic autoimmune disease which affects the kidneys. It is a rare (orphan) disease which leads to end-stage renal disease (ESRD) in a significant number of patients. It is a slowly progressing disease and it will in most cases take 10 to 20 years to progress to ESRD. It is caused by a specific type of antibodies, normally located in the gut mucosa that certainly appears in the blood. These antibodies forms complexes of antibodies that gets trapped in the glomeruli of the kidneys. These glomeruli normally filter waste and excess water from the blood and send them to the bladder as urine. However, in IgA patients this filtration mechanism is impaired by the trapped immune complexes which lead to leakiness of of blood and protein to the urine, and eventually destruction of the glomeruli's ability to filter the blood.

IgA anti bodies are a normal part of the body’s gut related immune system. It is not known exactly how, but IgA, antibodies with a small defect appear in the blood, where they are not supposed to be. This results in an auto-immune response from the body which generates other antibodies aimed to fight/remove these foreign bodies. These large immune complexes ultimately end up clogging up the kidneys’ filtration mechanisms, the glomeruli. A genetic predisposition is required but not enough in order to develop the disease. It has been showed that in more than 10% of affected families, it is inherited. In addition, it is assumed that bacterial, environmental or dietary impact is required to trigger the disease.

IgA nephropathy is a silent disease that may go unseen for years. It is most often diagnosed when patients are in their 20s and 30s and is in the western world more common in men than in women. The most common symptoms are protein in the urine (proteinura) and/or blood in the urine (hematuria). It can however take many years to progress to the stage where the kidneys’ filtration capacity is compromised.

The most common reason for a health care provider to refer a patient to a nephrologist for further tests is protein or blood in the urine, which is an indication of kidney damage. Ultimately, the final diagnosis of IgA requires a kidney biopsy to identify IgA deposits in the kidney tissue. For this test, a needle is used to sample of kidney tissue for examined under a microscope.

Currently, there are no approved treatments for IgAN. Blood pressure medication is often recommended as it can reduce the leakiness of protein into the urine, but it is uncertain whether it actually prevent any damage to the kidney. For views relating to potential treatment alternatives please review the KDIGO guidelines or speak to a health care provider.