THE SIGNIFICANCE OF THE DUST-LIKE PARTICLES PATTERN OF IMMUNOFLUORESCENCE - A STUDY OF 66 CASES

Subacute cutaneous lupus erythematosus (SCLE) isa marker of a unique s ubset of lupus erythematosus patients. A 'dust-like particles' direct immunofluorescence (DIF) staining pattern, which consists of fine gran ular particles of immunoglobulin(s) scattered through the epidermis an d the cellular infiltrates of the dermis. was reported to be specific for SCLE. In this study, we assessed the real specificity of this stai ning pattern, which had not yet been evaluated. We systematically sear ched for the dust-like particles staining pattern among the 4374 skin biopsy specimens submitted for direct cutaneous immunofluorescence dur ing a 7-year period (1989-96). The corresponding patient records were reviewed. Dust-like particles were observed in 66 samples originating from 60 patients. Only 53% of the patients had SCLE. The remaining pat ients had systemic lupus erythematosus with visceral involvement (17%) , discoid lupus erythematosus (3%), mixed connective tissue disease (2 %), Sjogren syndrome (2%) and other diseases. Eighty-five per cent of the patients had connective tissue disease. Seventy-seven per cent of the patients were positive for antinuclear antibodies, but only 36% we re positive for anti-Ro (SSA) antibodies. This study shows that the du st-like particles staining pattern is not specific for SCLE, but is hi ghly suggestive of connective tissue disease. The nature of the antige n responsible for the immunoglobulin deposition and the prognostic sig nificance of this DIF pattern remain to be established.