Genetic Susceptibility and Influence of the Microbiomae in Bullous Pemphigoid

Autoimmune bullous dermatoses include pemphigus, bullous pemphigoid, pemphigoid gestationis, linear IgA dermatosis, mucous membrane pemphigoid, lichen planus pemphigoid, anti-p200 pemphigoid, epidermolysis bullosa acquisita and dermatitis herpetiformis. Autoimmune bullous dermatoses are rare and have an incidence of 20-60 new cases per 1 million person- year in Europe. The incidence of the individual entities is slight significantly different within Europe, but strongly also in comparison to other countries such as Kuwait, Singapore, USA and South America. The most common of these disorders is the bullous pemphigoid.

A considerable progress has been made in the last years to elucidate the pathogenic role of autoantibodies in these diseases. To this end, various in vitro and animal experiments have been used to understand some basic pathophysiological mechanisms in these diseases. Further studies are currently being carried out to explain a precise elucidation of the disease process and to be able to treat the patients targeted later.

At present, however, no data are available to explain why certain individuals develop the autoimmune disease and others do not. Epidemiological studies showed some triggers to the development of autoimmune dysregulation, e.g. drugs.

Furthermore, it has been shown that genetic factors play a role in the pathogenesis of the disease. A clear association with certain HLA regions have been shown in patients with pemphigus, e.g. about 95% of pemphigus patients from the group of Ashkenazi Jews have the HLA-DRB1*0402 haplotype. Recently, the first non-HLA gene associated with pemphigus was described. For other conditions such as bullous pemphigoid, pemphigoid gestationis or linear IgA dermatosis the association with HLA antigens is less pronounced. Another indication of the importance of the genetic background in these diseases can be elucidated from the observation of autoantibodies at a low concentration in healthy relatives of pemphigus patients.