Expression of Neutrophil Elastase in Relation to the Autoimmunity

Activated inflammatory cells, especially neutrophils, may play a significant role in pathology of autoimmune bullous dermatoses by secreting proteases, e.g. neutrophil elastase (NE). However, the role of NE in relation to autoimmunity against particular autoantigens (anti-DSG1/DSG3 IgG in pemphigus, anti-BP180/BP230 IgG in bullous pemphigoid - BP, anti-eTG/tTG/npG IgA in dermatitis herpetiformis - DH) has not been clearly explained. The aim of this comparative work was to attempt to clarify the intertwined issue of cutaneous autoimmune NE-mediated inflammation in those diseases. Six different study groups were investigated and a range of biochemical/molecular techniques was used. Computational analysis of microscopic images was used to measure the NE expression. Statistical analysis showed that the intensity of cutaneous NE expression in pemphigus and BP was significantly lower than in DH, but it was not significantly different in pemphigus and BP. It seems that cutaneous NE-related inflammatory processes in both pemphigus and BP, characterised by autoimmunity to structural proteins, have lesser pathologic importance in comparison with DH, characterised by autoimmunity to enzymes.