Although primary Sjogren's syndrome is often a benign condition, characterized by lymphocytic infiltration of salivary and lacrimal glands, some patients develop systemic features. We have previously found that anti-Ro antibodies identified patients with more systemic disease, with increased incidence of parotid swelling, lymphadenopathy and lymphoma.
We have followed up a cohort of 100 patients over 10 yr, to establish whether the phenotypic expression of disease changed, and whether the different autoantibody patterns expressed at presentation could be used to predict outcome.
While seronegative patients (ANA, RF, Ro and La negative) remained polysymptomatic, they did not develop systemic complications or serological changes. Thirty-nine per cent of ANA- or RF-positive patients who were negative for Ro and La were given revised diagnoses over the follow-up period, including rheumatoid arthritis, systemic lupus erythematosus, mixed connective tissue disease and scleroderma. Parotid swelling and lymphadenopathy were more common in Ro/La-positive patients, where the relative risk of developing non-Hodgkin's lymphoma was 49.7.
Both HLA B8 and DR3 were present in 79% of Ro/La-positive patients, but were found together in only 4% of seronegative patients, supporting the view that these clinical subgroups of primary Sjogren's syndrome are both serologically and immunogenetically distinct. Patients who are initially autoantibody (including Ro and La) negative do not evolve into 'systemic' Sjogren's syndrome or other connective tissue diseases.