How reliable is the basement membrane phenomenon in the diagnosis of systemic lupus erythematosus?

BACKGROUND

Although the basement membrane (BM) phenomenon is considered a good test to differentiate between systemic (SLE) and discoid lupus erythematosus (DLE), our observations question its reliability.

METHODS

Direct immunofluorescence stain was done to detect immunoglobulins and complement deposits in 10 SLE patients and in 10 healthy controls. Specimens were taken from the normal skin of the dorsa of hands.

RESULTS

The group of SLE patients showed deposits of IgG in 4, IgM in 7, IgA in 1, C3 in 7, and C4 in 1 patient. The group of healthy controls showed IgM in 2, C3 in 5, C4 in 2 cases, but no IgG or IgA deposits.

CONCLUSION

A positive BM phenomenon test could be found in normal individuals and may be due to the effect of ultraviolet rays. We think that the BM phenomenon has a limited reliability in diagnosing SLE.