Direct Immunofluorescence
Also written as: DIF — Direct Immunofluorescence
A laboratory technique applied to fresh perilesional tissue to detect in-situ deposition of immunoglobulins and complement in autoimmune mucocutaneous disorders.
Full Definition
Direct immunofluorescence (DIF) involves the application of fluorescently labelled antibodies directly to a section of the patient's own tissue (typically perilesional mucosa) to identify immune deposits. In oral medicine, DIF is the diagnostic gold standard for autoimmune vesiculobullous conditions such as pemphigus vulgaris, mucous membrane pemphigoid, and linear IgA disease. The pattern of fluorescence—whether intraepithelial, linear, or granular along the basement membrane—guides the specific diagnosis. Editors should distinguish DIF from indirect immunofluorescence (IIF), which tests the patient's serum against an exogenous substrate. Both abbreviations (DIF and IIF) should be defined at first use.
Usage
Usage note: Tissue for DIF must be transported in Michel's medium, not formalin; editors reviewing methods sections should flag discrepancies in specimen handling.
In Context
- "Direct immunofluorescence of the perilesional biopsy revealed intercellular IgG deposits consistent with pemphigus vulgaris." — Oral pathology report
- "The authors should clarify whether direct immunofluorescence (DIF) or indirect immunofluorescence (IIF) was performed." — Manuscript peer review