Autoantibodies are present many years before symptom onset in patients with primary Sjögren syndrome, an autoimmune disease, according to a Research Letter published in the November 6 issue of JAMA.
Primary Sjögren syndrome is a disease in which immune cells attack and destroy glands that produce tears and saliva. Autoantibodies are characteristic of this syndrome and may be involved in its development. Roland Jonsson, D.M.D., Ph.D., of the University of Bergen, Norway, and colleagues measured autoantibodies before symptom onset in these patients.
All patients with primary Sjögren syndrome at Malmo University Hospital in Malmo, Sweden, have been included in a registry since 1984. Controls were randomly selected from biobanks and matched by sex, age, and date of earliest sampling (within 60 days before or after) to each case.
Of 360 cases in the registry, 44 (41 women and 3 men) provided 64 presymptomatic serum samples obtained an average of 7 years before symptom onset. In 29 cases (66 percent), autoantibodies were detected before symptom onset. All 29 cases had autoantibodies in their earliest available serum sample, as early as 18 years before symptom onset.
"To our knowledge, this is the first systematic investigation of presymptomatic autoantibodies in Sjögren syndrome. Most cases produced autoantibodies many years before clinical onset of the disease; the median [midpoint] time of 4 to 6 years is an underestimate because all seropositive cases had autoantibodies in their earliest available serum sample," the authors write.
"Autoantibody profiling may identify individuals at risk many years before disease onset. However, the significance of these presymptomatic autoantibodies for determining prognosis and treatment remains to be determined."
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