Low Strength of Correlation between the Intensity of Neutrophil Elastase Expression in Lesional Skin and the Level of Serum IgA Antibodies to Epidermal Transglutaminase in Dermatitis Herpetiformis

Whereas it has been shown that neutrophil elastase (NE) is a crucial enzyme degrading the dermal-epidermal junction (DEJ) in bullous pemphigoid (BP), experimental studies on the role of NE in dermatitis herpetiformis (DH), a disease in which, as in BP, an intra-lamina lucida blister is formed, are scanty. The aim of this study was to analyse whether there is a correlation between levels of serum IgA antibodies to the epidermal transglutaminase (TG3), an enzyme believed to be the autoantigen of DH, and expression of NE in lesional skin in DH. A series of 21 consecutive patients with DH was studied. The levels of IgA antibodies to TG3 in sera were calculated with ELISA. The expressions of NE were examined with immunohistochemical technique in sections of lesional skin using a mouse monoclonal antibody to human NE. The digital microscopic image analysis with the appropriate software was then used to measure intensities of NE expression. The correlation between the intensity of NE expression in lesional skin and the level of serum IgA antibodies to TG3 in DH was of low strength. Thus, it is speculated that in DH the engagement of IgA autoantibodies to the enzyme, TG3, on cutaneous neutrophils might not be a principal stimulus to releasing NE, the enzyme known to degrade DEJ in subepidermal blistering diseases with autoimmunity to DEJ structural proteins.