Researchers funded in part by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) have identified the basis for a test that would save patients with systemic lupus erythematosus (lupus) the expense, discomfort, and potential complications of repeated kidney biopsies.
People with lupus often develop renal (kidney) disease, which may sometimes lead to end-stage renal disease (ESRD). Currently, the only way to tell if a patient has renal disease--and which of the six types it might be--is by taking a biopsy of the kidney. This involves inserting a needle into the kidney and removing a sample of tissue for analysis. Since patients may develop different types of kidney disease at different times and in different severities, they frequently need repeated biopsies to determine the exact kind of disease and the most effective treatment.
Jim C. Oates, M.D., of the Medical University of South Carolina, and his colleagues, studied urine samples collected from 20 patients immediately before they underwent kidney biopsy. Using a process known as two-dimensional gel electrophoresis, they looked for proteins in the urine samples that could be biomarkers for lupus-related kidney disease. These results were then compared with the findings from the kidney biopsies.
The researchers were able to identify a list of proteins in the urine of people with renal disease caused by lupus. These biomarkers can be used to indicate the type and severity of renal disease in these patients, as well as the extent of damage to the kidney. Such biomarkers could form the basis of clinical tests that could help doctors to establish an effective treatment plan for these patients without putting them through repeated kidney biopsies. Further studies are needed to determine whether urine protein analysis could replace the use of biopsies to assess kidney damage in lupus.
Lupus is an autoimmune disease, one in which the immune system attacks healthy tissue. This leads to inflammation and damage to various body tissues. Lupus can affect many parts of the body, including the joints, skin, kidneys, heart, lungs, blood vessels and brain. In 2002, about 1,100 patients developed lupus-related ESRD in the United States.
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov.
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Oates J, et al. Prediction of urinary protein markers in lupus nephritis. Kidney International 2005;68:2588-2592.