Advanced Diagnostic Techniques in Autoimmune Bullous Diseases

Abstract

Autoimmune blistering diseases are diverse group of conditions characterized by blisters in the skin with or without mucosal lesions. There may be great degree of clinical and histopathological overlap; hence, advanced immunological tests may be necessary for more precise diagnosis of these conditions. Direct immunofluorescence microscopy is the gold standard tests to demonstrate the tissue-bound antibodies and should be done in all cases. Magnitude of antibody level in patient' serum can be assessed by indirect immunofluorescence and enzyme linked immunosorbent assay. In this article we have reviewed the various techniques that are available in the diagnosis of autoimmune blistering diseases.

Keywords: Autoimmune bullous diseases; ELISA; direct immunofluorescence.

Figure 1

Algorithmic steps in the advanced diagnosis of autoimmune blistering diseases

Figure 2

(a) Schematic diagram showing important steps in the direct immunofluorescence test. (b) Steps involved in indirect immunofluorescence

Figure 3

(a) Salt-split study showing linear basement membrane zone band on the epidermal side of the split (“roof pattern”) with IgG (red circle representing the level of split. (b) Linear basement membrane zone band on the dermal side (“floor pattern”) of the split with IgG (red circle denotes the level of split) (FITC, ×200)

Figure 4

Schematic diagram of an enzyme-linked immunosorbent assay system. Intensity of final yellow color is related to the amount of circulating antibodies

Figure 5

(a) Intercellular staining of epidermis with IgG in pemphigus and (b) linear staining of basement membrane zone with C3 in bullous pemphigoid (FITC ×200)

Figure 6

Schematic diagram showing target antigens of paraneoplastic pemphigus with their molecular weights

Figure 7

(a) Direct immunofluorescence showing dual pattern (“intercellular staining and basement membrane zone”) of staining with IgG in paraneoplastic pemphigus (FITC, ×40). (b) Indirect immunofluorescence using rat bladder showing staining of transitional epithelium. (c) Negative control in rat bladder (FITC, ×200)

Figure 8

Schematic diagram showing various antigens at dermoepidermal junction. Common antigenic targets in subepidermal immunobullous diseases are BP180 (bullous pemphigoid, mucous membrane pemphigoid, pemphigoid gestationis, and LAD), BP230 (bullous pemphigoid), integrins α6 β4 (mucous membrane pemphigoid), laminin 332 (mucous membrane pemphigoid), laminin γ1 (p-200 pemphigoid) and collagen VII (epidermolysis bullosa acquisita)

Figure 9

(a) Linear staining of basement membrane zone with IgG (on either side of the split) in mucous membrane pemphigoid. (b) Granular staining of dermal papillae with IgA in dermatitis herpetiformis (FITC, ×200)

Figure 10

Algorithmic chart showing immunofluorescence findings in various autoimmune bullous diseases