Serum anti—SS‐B/La and IgA rheumatoid factor are markers of salivary gland disease activity in primary sjögren's syndrome

Objective . To identify serologic markers of salivary gland disease activity in 43 patients with primary Sjögren's syndrome. Methods . Comparison of salivary gland biopsies (focus scores) and flow rates with serum concentrations of IgA and IgM rheumatoid factor (RF), total serum IgG, serum anti—SS‐B/La antibodies, and the erythrocyte sedimentation rate. Results . Serum anti—SS‐B/La antibody levels correlated with focus scores (r s = 0.477, P < 0.0025). Serum IgA‐RF concentrations correlated inversely with stimulated parotid gland salivary flow rates (r s = −0.394, P < 0.01). Conclusion . Measuring serum levels of anti—SS‐B/La and IgA‐RF would be useful when monitoring salivary responses in therapeutic trials, especially in patients with minimal salivary function.