Western blot band intensity analysis. Application to the diagnosis of Lyme arthritis.

OBJECTIVE

To determine the usefulness of quantitative band-intensity analysis of Western blots for the diagnosis of Lyme arthritis.

METHODS

IgG Western blots for antibodies to Borrelia burgdorferi were performed on sera from 39 patients with Lyme arthritis, 30 patients with syphilis, 50 patients with connective tissue diseases, and 10 healthy individuals. Band positions and band intensities were calculated using a computerized image analysis system.

RESULTS

Lyme arthritis patients had more bands and higher-intensity bands than did non-Lyme patients. The presence of at least 2 bands of moderate to high intensity (> 40 optical units) or at least 5 bands of lower intensity (> 20 optical units) was over 90% sensitive and 100% specific for the diagnosis of Lyme arthritis. A 60-kd band was present in all Lyme arthritis patients. The presence of an 83-, 39-, 21-, or 18-kd band was highly specific for Lyme arthritis.

CONCLUSION

Band intensity analysis increases the objectivity and accuracy of Western blot interpretation for the diagnosis of Lyme arthritis.