Interferon effects on the kidney

Interferons are cytokines which play a central role in the inflammatory response, and commercially prepared interferons have proven useful in the treatment of several diseases. For instance, interferon-alpha (often used in conjunction with ribavirin) is often used in the treatment of hepatitis C, and has also proven useful in the treatment of certain cancers, such as malignant melanoma. Interferon-beta has also been very successfully used in the treatment of multiple sclerosis. With the increasing use of interferons, however, has come the realization that they can have renal side effects in some patients.

A variety of mechanisms of injury have been reported, though most attention has focused on the ability of interferon therapy to cause proteinuria and nephrotic syndrome. This has been noted most commonly with interferon-alpha therapy, though in many of the patients with hepatitis B or C it may be difficult to be certain whether or not the development of nephrotic syndrome comes from the interferon therapy or a direct hepatitis-mediated renal injury such as MPGN. There have also been some recent case reports suggesting that interferon-beta can also cause a minimal change nephrotic syndrome in patients treated for multiple sclerosis and malignant melanoma.

Other mechanisms of renal injury reported with interferon use include acute tubular necrosis, acute interstitial nephritis, and even hemolytic-uremic syndrome. Occasionally, tubuloreticular structures as seen on electron microscopy of a kidney biopsy can be a clue as to the diagnosis of interferon-induced renal injury; these may also be seen in HIV-associated nephropathy.