A team of lupus researchers has identified a potential new biomarker that may be helpful in determining whether a person with lupus is at risk for developing organ damage.
New Blood Tests May Improve the Tracking of Lupus Kidney Disease in Children
Markers of childhood lupus nephritis indicating disease activity
Edelbauer M, Kshirsagar S, Riedl M, Haffner D, Billing H, Tönshoff B, Ross S, Dötsch J, Amon O, Fehrenbach H, Steuber C, Beissert A, Hager J, Wechselberger G, Weber LT, Zimmerhackl LB. (2010). Pediatric Nephrology: epub ahead of print.
What is the topic?
Current treatments for lupus nephritis in children are toxic and sometimes ineffective. New tests for proteins that might be abnormal in lupus nephritis could help make the diagnosis earlier (when treatments have a better chance to work more quickly) and might also point to new ways of treating the disease (possibly with fewer side effects).
What did the researchers hope to learn?
The researchers hoped to find new tests for lupus nephritis in children.
Who was studied?
22 children with lupus nephritis, 13 children with severe loss of protein from nephritis, and 20 healthy children participated in the study.
How was the study conducted?
This study took place in Germany and Austria. A number of blood tests were done to look for different kinds inflammation. Lupus activity was scored using an index called the SLEDAI-2K. All of the patients had developed nephritis before the age of 16. Most of the patients were being treated with immune-suppressing drugs, including cyclophosphamide (Cytoxan®), mycophenolate mofetil (CellCept®), and/or prednisone.
What did the researchers find?
Nephritis was the first sign of lupus in 20 of the 22 children. Only 5 of the 22 children with nephritis had other signs of lupus, such as arthritis, at the time of the study. This would not be surprising since they were being given strong treatments for the kidney inflammation.
Levels of a protein called BAFF (BLyS) were lower in children with inactive lupus nephritis compared to active nephritis, but still higher than in healthy children. Levels of BAFF were similar between children with inactive lupus nephritis and those with heavy protein loss. This was also true for another protein associated with blood vessel inflammation called VCAM1.
There were several other tests for inflammatory proteins that were highest in children with active nephritis, intermediate in those with inactive nephritis, and less in those with severe loss of protein from nephritis and/or in healthy children. Children with active nephritis had lower levels of an inflammatory protein (complement protein) called C1q, and they also had higher levels of antibodies that attack this protein.
What were the limitations of the study?
This study included a small number of patients and the tests were only done once. Larger studies that measure these proteins over a period of time in different patients with different outcomes would be the next step in figuring out the potential value of these tests.
What do the results mean for you?
New blood tests may eventually be developed that can predict kidney flares in children with lupus, help to test the effects of new treatments, and guide the optimal use of medications. There is still a lot of work to be done on these tests and they are not widely available at this time.
The use of lupus biomarkers, such as those present in the blood or urine, to help predict and/or manage lupus nephritis over time could be very useful. The results of this study highlight the potential feasibility of using lupus biomarkers to differentiate between acute and chronic kidney disease activity-related changes.