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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.