Primary Sjögren's syndrome, an autoimmune disease that affects four million Americans (90 percent of whom are women), attacks moisture-producing glands, creating such problems as chronic dry eyes, dry mouth, and arthritis. Some other reported conditions are lymphoma, thyroid dysfunction, painful peripheral neuropathy, and gastrointestinal problems. For the thousands of Americans who will be evaluated this year for primary Sjögren's syndrome, their doctors likely will test for two antibodies, called SSB and SSA, that often are associated with the syndrome. The problem is that today's standard blood tests detect the more strongly associated antibody SSB only about half of the time, making the meaning of a negative result uncertain.

     Enter scientists at the NIH National Institute of Dental and Craniofacial Research (NIDCR). They report that a rapid, automated test now under development, called luciferase immunoprecipitation technology (LIPS), identified the SSB antibody correctly three out of four times with perfect accuracy. It also detected the SSA antibody almost as well as the current standard assays in their initial study of 82 people. Of that group, 57 had well-characterized primary Sjögren's syndrome.

     Scientist Peter Burbelo, Ph.D., and colleagues report using LIPS to profile additional antibodies of interest that may be related to other largely unrecognized manifestations of the syndrome. These first-pass antibody profiles have the potential to help scientists define, for the first time, a range of clinical subtypes of primary Sjögren's. That could improve greatly the diagnoses of the syndrome and possibly better target treatment.

     To date, Dr. Burbelo and colleagues have published intriguing data involving LIPS and a range of autoimmune conditions, from type 1 diabetes to herpes simplex virus, which can cause herpes zoster, an autoimmune disease. Findings suggest that LIPS may have the potential to detect most developing autoimmune disorders before they become symptomatic, more closely monitor the ups and downs of a patient's antibody counts over time, and track the immunological outcome of an autoimmune treatment. The findings also suggest that LIPS may be used as a substitute for more invasive and expensive procedures typically used to diagnose the aforementioned peripheral conditions.

     Dr. Burbelo cautions that this study is just a start. He says, "All of these tests can be performed on the automated robotic machine in my laboratory, and we can do thousands a day. There's more data to come."
 

--Source: "Diagnostic Technique Shows Promise for Primary Sjögren's Syndrome," NIH News, August 18, 2009