RESUMEN
OBJECTIVES: Antikeratin antibody is an autoantibody to the cornified epithelium of rat esophagus and known to be a specific marker in Caucasian patients with rheumatoid arthritis. This study was performed to evaluate the prevalence and clinical correlation of the antibody in Korean patients with rheumatoid arthritis. METHOD: We measured antikeratin antibodies by indirect immunofluorescence method and evaluated functional class, anatomical stage, grip strength, Ritchie articular index, tender joint count, swollen joint count, rheumatoid factor and antinuclear antibody in 88 patients with rheumatoid arthritis, 20 patients with systemic lupus erythematosus and 43 healthy controls. RESULTS: The sevsitivity and specificity of the antikeratin antibody test was 48% and 98% respectively in Korean patients with rheumatoid arthritis. Intensity of antikeratin antibody was correlated with duration of morning stiffness(r=0.22, p=0.01) and rheumatoid factor titer(r=0.23, p=0.04). Antikeratin antibody was positive in 8(31%) out of 26 patients without rheumatoid factor. CONCLUSION: Antikeratin antibody is a specific marker in Korean patients with rheumatoid arthritis and correlated with duration of morning stiffness and rheumatoid factor titer.