Anti-Ro52 antibody testing influences the classification and clinical characterisation of primary Sjögren's syndrome.

OBJECTIVES: To evaluate how determination of antibodies against the Ro52 antigen influences the classification and clinical characterisation of patients with suspected primary Sjögren's syndrome (SS). METHODS: The cohort study included 187 patients who fulfilled at least four of the six 1993 SS classification criteria, including positive autoantibodies (antinuclear antibodies [ANA], rheumatoid factor [RF], anti-Ro/SSA and/or anti-La/SS-B antibodies) as mandatory criterium. Anti-Ro/SSA antibodies were tested by qualitative ELISA using a commercial assay. Anti-Ro52 antibodies were detected by a semiquantitative ELISA. RESULTS: Anti-Ro52 antibodies were found in 70/187 (37%) patients. A significant percentage of patients with anti-Ro/SSA antibodies were negative for anti-Ro52 antibodies (22%), while 13 patients (12%) were negative for anti-Ro/SSA antibodies but positive for anti-Ro52 antibodies, meaning that they fulfilled the 2002 SS criteria while avoiding the need for a salivary biopsy. Higher mean titers of anti-Ro52 antibodies were associated with severe scintigraphic involvement, positive salivary gland biopsy, parotid enlargement, anaemia, leukopenia and RF. A statistical correlation was found between anti-Ro52 titers and age, gammaglobulin levels, RF titers and serum IgA and IgG. Patients with positive anti-Ro/SSA and anti-Ro52 antibodies had a higher frequency of positive salivary gland biopsy, parotid enlargement and positive RF, and higher levels of serum IgG and IgA levels in comparison with patients with positive anti-Ro/SSA but negative anti-Ro52 antibodies. CONCLUSIONS: Anti-Ro52 antibodies were closely associated with the main clinical, histopathological and immunological features of primary SS. Anti-Ro52 autoantibody testing may help to identify a specific subset of SS patients with more aggressive disease, in whom a closer follow-up and earlier, more robust therapeutic management may be necessary.