Lupus nephritis

Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus (SLE), a disease of the immune system. Apart from the kidneys, SLE can also damage the skin, joints, nervous system and virtually any organ or system in the body.

Signs and symptoms

Sufferers of lupus nephritis may or may not have symptoms of kidney disease, but it can manifest itself through weight gain, high blood pressure, darker foamy urine or swelling around the eyes, legs, ankles or fingers.

Histologically a wire-loop lesion will be present. The wire loop lesion is a glomerular capillary loop with subendothelial immune complex deposition that is circumferential around the loop.

Furthermore, patients may suffer from other symptoms of lupus unrelated to kidney function. Such symptoms can include arthritis, fevers, gastro-intestinal disturbances, headaches, fatigue, and fluid in the joints.

Diagnosis

The diagnosis of lupus nephritis depends on blood tests, urinalysis, X-rays, ultrasound scans of the kidneys, and a kidney biopsy.

The World Health Organization has divided lupus nephritis into five classes based on the biopsy. This classification was defined in 1982 and revised in 1995.

• Class I is minimal mesangial glomerulonephritis which is histologically normal on light microscopy but with mesangial deposits on electron microscopy.
• Class II is based on a finding of mesangial p roliferative lupus nephritis. This form typically responds completely to treatment with corticosteroids.
• Class III is focal proliferative nephritis and often successfully responds to treatment with high doses of corticosteroids.
• Class IV is diffuse proliferative nephritis. This form is mainly treated with corticosteroids and immunosuppressant drugs.
• Class V is membranous nephritis and is characterized by extreme edema and protein loss.
• Class VI Glomerulosclerosis

Medicines that decrease swelling, lower blood pressure, and decrease inflammation by suppressing the immune system: Patients may need to monitor intake of protein, sodium, and potassium. Patients with severe disease should restrict their sodium intake to 2 grams per day and limit fluid as well. Depending on the histology, renal function and degree of proteinuria, patients may require steroid therapy or chemotherapy regimens such as cyclophosphamide, azathioprine, mycophenolate mofetil, or cyclosporine.

(Lupus Nephritis -- Diffuse Proliferative)

The medical therapy for lupus nephritis depends on the severity of the disease. For mild disease, corticosteroids are, in general, prescribed. More severe disease requires treatment with immunosuppressant agents. The two most commonly-used agents are mycophenolate mofetil and intravenous cyclophosphamide. One recent study compared these two drugs. The authors showed that patients with Class III or IV disease are more likely to benefit from mycophenolate mofetil as compared to cyclophosphamide. However, a larger study by the same authors that directly compared these therapies did not show that Mycophenolate was superiour to cyclophosphamide except in non-caucasian non-asian patients. In caucasian or asian patients both treatments worked equally well. There was no overall difference in safety in this trial, although cyclophosphamide may induce permanent infertility in young women, which is a significant drawback. As a result, mycophenolate mofetil is now considered to be an alternative therapy for this disease.