Cutaneous Immunofluorescence, Biopsy
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Skin or mucosal tissue from patients with autoimmune bullous diseases, connective tissue disease, vasculitis, lichen planus, and other inflammatory conditions often contains bound immunoglobulin, complement, and/or fibrinogen.
Biopsy specimens are examined for the presence of bound IgG, IgM, IgA, third component of complement (C3), and fibrinogen.
Confirming a diagnosis of bullous pemphigoid, cicatricial pemphigoid, variants of pemphigoid, all types of pemphigus, dermatitis herpetiformis, linear IgA bullous dermatosis, chronic bullous disease of childhood, epidermolysis bullosa acquisita, porphyria cutanea tarda, bullous eruption of lupus erythematosus, herpes gestationis, and atypical or mixed forms of bullous disease, systemic lupus erythematosus, discoid lupus erythematosus, or other variants, vasculitis, lichen planus, and other inflammatory diseases.
In pemphigus, direct immunofluorescence (IF) testing will show deposition of IgG, or rarely IgA, and often complement C3 (C3) at the cell surface (intercelluar substances).
In bullous pemphigoid and cicatricial pemphigoid, direct IF study demonstrates deposition of IgG and C3 at the basement membrane zone (BMZ) in a linear pattern.
In cicatricial pemphigoid, a disease uncommonly associated with circulating anti-BMZ antibodies, direct IF testing is particularly useful.
Biopsy from patients with dermatitis herpetiformis will show IgA concentrated in dermal papillae and/or in a granular pattern at the BMZ.
In lupus erythematosus (LE), there are granular deposits of immunoglobulin and complement at the BMZ ("lupus band"). A lupus band is typically found in lesional skin from patients with a variety of forms of LE; similar findings in biopsies of uninvolved "normal" skin are consistent with systemic LE.
Biopsy of early inflammatory purpuric lesions of vasculitis will show immunoglobulins and/or complement in dermal vessels.
The diagnostic value of direct IF testing is illustrated in the chart Results of IF Testing under Cutaneous Immunofluorescence Testing in Special Instructions.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
In most cases, diagnosis should be confirmed by correlating the results of immunofluorescence testing with clinical information and histologic studies.
Not useful for diagnosis of malignancies involving the skin.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Report includes description and interpretation of staining patterns. See Results of IF Testing in Cutaneous Immunofluorescence Testing in Special Instructions.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
Immunopathology of the Skin. Edited by EH Beutner, TP Chorzelski, V Kumar. Third edition. New York, NY, Wiley Medical Publication, 1987