Chronic discoid lupus erythematosus in Thailand: direct immunofluorescence study.

BACKGROUND

Studies of chronic discoid lupus erythematosus (DLE) lesions by direct immunofluorescence (DIF) were heterogeneous with respect to classes of immunoglobulins and sites where these were deposited. Most of the studies were done in the USA and European countries.

MATERIALS AND METHODS

To obtain representative data from Asiatic countries, we analyzed the direct immunofluorescent abnormalities of 100 DLE lesions in Thai patients who were diagnosed on the basis of clinical and histologic criteria.

RESULTS

Granular deposits at the dermoepidermal junction (DEJ) were detected in 90% of cases. The common immunoreactants at the DEJ were IgG (63%) and IgM (47%). The deposits were usually combinations of various classes of immunoglobulins, mostly IgG (53%) and IgM (41%). Deposits of IgG and IgM alone at the DEJ were observed in 12% and 8%, respectively. Deposits at colloid bodies, dermal blood vessel walls, and epidermal nuclei were sometimes also seen.

CONCLUSIONS

The DIF test of skin biopsy specimens is diagnostically significant in chronic DLE. Our study in Thai patients showed that the most common deposit was a combination of various classes of immunoglobulins, mostly IgG and often IgM as well as C3, and occurred at the DEJ of the involved area.