To investigate the clinical significance of beta2-microglobulin in Korean patients with systemic lupus erythematosus (SLE). Methods: Blood samples were collected from patients with SLE (n ϭ 100) and normal healthy controls (n ϭ 50). The level of beta2-microglobulin was investigated by enzyme-linked immunosorbent assay. Serial samples from SLE patients were collected at 4.2 Ϯ 2.6 months after first sampling. Results: The beta2-microglobulin levels of the SLE patients (2.64 Ϯ 0.11 g/mL) were

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... r than the normal controls (2.14 Ϯ 0.04 g/mL, P Ͻ 0.001). The patients with SLE with serositis, oral ulcer, or lupus nephritis had significantly higher beta2-microglobulin levels than those without, respectively. A significant correlation was found between the beta2-microglobulin level and each of anti-dsDNA antibody, hemoglobin, complement, and SLE Disease Activity Index. In sequential sampling of patients with SLE, a positive correlation was found between the change of the SLE Disease Activity Index and the change of the beta2-microglobulin levels. Conclusions: These data suggest that the measurement of beta2-microglobulin seem to be a useful addition to the laboratory tests that can help in assessment of disease activity of SLE.