Contemporary Possibilities of Immunochemical Diagnosis of Autoimmune BullousDiseases in the Zone of the Epidermal Basement Membrane

Overview

Contemporary development of findings concerning bullous diseases, associated with the steadyincrease of new pathological units with a clinically similar morphology but different pathogenesisand different therapeutic requirements, makes dermatological departments face pretentious tasksassociated with the diagnosis of these diseases.The objective of the present work is a review of immunomorphological methods recommendedby the authors to dermatological departments to cope with the diagnosis of bullous diseases. The authors used for assessment of bullous diseases the method of direct immunofluorescencefor estimation of deposits of IgG, IgA, the C3 component of complement in tissues, the method ofindirect immunofluorescence on the monkey and pig oesophagus resp., on the salt split skin test, ontrypsin and dispase substrates to assess circulating IgG andIgA antibodies,immunoblotting to detectwith which antigens these antibodies react and to assess the structure of the bulla by means oflaminine, fibronectin and collagen type IV.Based on their experience the authors recommend the following procedure: 1. Routine histologicalexamination which makes possible assessment of the presence of subepidermal bullous disease.2. Direct immunofluorescent method which assesses deposits in the IgG and IgA class and makes itpossible to differentiate pemphigoids from linear IgA dermatosis and dermatitis herpetiformis.3. Indirect immunofluorescence using separated skin in hypertonic NaCl solution which in case ofthe presence of circulating antibodies makes possible the differential diagnosis of pemhigoids fromepiligrine pemphigoid and epidermolysis bullosa acquisita and linear IgA dermatosis from IgAepidermolysis bullosa acquisita. 4. The use of substrates treated with trypsin or dispase which makepossible the differential diagnosis of epiligrine pemphigoid from epidermolysis bullosa acquisita.5. In case of the presence of circulating autoantibodies it is possible to use immunoblotting to assessantigens with which the patient’s autoantibodies react. 6. Immunohistological assessment of the siteof the blister in the zone of the basal membrane which is particularly important in the absence ofcirculating antibodies.

Key words:
bullous dermatoses - direct fluorescence - indirect immunofluorescence - salt split skintest - laminine - fibronectin - collagen type IV - immunoblotting