Autoimmune dermatoses

The diagnosis of autoimmune dermatoses depends upon the detection of autoantibodies, both tissue-bound and circulating. For circulating antibodies, the patient’s serum is looked up for antibodies against epidermal antigens (prickle cell desmosomes and epidermal basement membrane antigen), using the indirect immunofluorescence (IFA) technique. To narrow down the spectrum, autoantibodies are also detected using tissue sections; those from the esophagus and primate salt-split skin. Final diagnosis stems from a combination of clinical presentation and the detection of antibodies using IFA, monospecific ELISA and immunoblot assays.

Patients with bullous pemphigoid come out positive for antibodies against BP180 and BP230. While those against BP180 correlate with the disease activity, antibodies against BP230 correlate with the duration of the disease. Thus, these antibodies not only help make a diagnosis but also help monitor the disease activity before and after the treatment. Also, they help to make a statement on disease duration.

Pemphigus diseases involve antibodies against desmoglein 1 and 3. High titers for these antibodies detected on IFA and ELISA (same sensitivity and specificity for both tests) are diagnostic of the disease.

For EBA, high levels of antibodies against collagen type 7 are observed. These antibodies play a dual role; they allow for both disease diagnosis and help differentiate it from other types of autoimmune dermatoses.