Anti–Skin antibodies

Autoimmune blistering diseases are organ-specific autoimmune conditions characterised by autoantibodies against structural skin proteins. They are divided into four main groups depending on target antigens and clinical presentation: pemphigoid diseases, pemphigus diseases—including epidermolysis bullosa acquisita (EBA)—paraneoplastic pemphigus, and dermatitis herpetiformis (DH).

Diagnosis and differentiation of autoimmune blistering diseases rely on clinical assessment combined with the detection of autoantibodies against specific target antigens.

Bullous pemphigoid (BP) is the most common autoimmune blistering dermatosis, mainly affecting older adults, and manifests with tense blisters on the skin. Autoantibodies in BP are directed against two hemidesmosomal proteins: BP180 (type XVII collagen) and BP230.

Pemphigus diseases can be classified clinically and immunopathologically into four different forms:

• Pemphigus foliaceus
• Pemphigus vulgaris
• IgA pemphigus
• Paraneoplastic pemphigus

In pemphigus, the immune system primarily targets the calcium-dependent adhesion molecules of desmosomes in the spinous layer: desmoglein 1 and 3 (Dsg1 and Dsg3).

Paraneoplastic pemphigus is associated with autoantibodies directed against several desmosomal and hemidesmosomal proteins: desmoplakin 1 and 2, BP230, envoplakin, periplakin, plectin, Dsg1, Dsg3, and an unknown 170 kDa antigen.

In dermatitis herpetiformis (DH), blisters form in the deeper layers of the skin. For serological diagnosis, antibodies against gliadin, epidermal transglutaminase, or tissue transglutaminase/endomysium are particularly relevant.

The indirect immunofluorescence test on primate tissue allows identification of distinct fluorescence patterns corresponding to different autoantibody profiles, thereby supporting the diagnosis of autoimmune blistering diseases.