There is a strong feeling among experts that some of the biologic therapies that have already had major impact in other rheumatic diseases hold promise in Sjögren's syndrome, but their successful application will require early identification of affected patients and reliable markers of disease activity, which the SICCA registry aims to provide, according to Dr. Baer.
The prevalence of Sjögren's syndrome is roughly 1 in 200. It is a disorder mainly of peri- and postmenopausal women; the female-to-male ratio is 20:1. The risk of lymphoma is the highest of all the autoimmune diseases, for reasons unknown. It's also unclear why up to 50% of patients with Sjögren's syndrome are seronegative.
The last 35 years have brought a succession of at least nine classification schemes for Sjögren's syndrome. All were wanting in various ways. The most liberal are the 1993 European criteria, which are limited by low specificity. The most recent criteria—the 2002 U.S./European consensus criteria—are cumbersome and, many believe, too restrictive.
Dr. Baer noted that the SICCA registry has borne early fruit in the form of a recently published simplified quantitative means for diagnosing the ocular component of Sjögren's syndrome. The investigators identified a large group of patients with keratoconjunctivitis sicca but none of the nonocular components of Sjögren's syndrome, a novel finding suggesting the existence of two different forms of keratoconjunctivitis sicca the causes of which may differ (Am. J. Ophthalmol. 2010;149:405-15).
Dr. Baer indicated he has no relevant financial relationships.