Related Experiment Videos
Membrane attack complex of complement in dermatitis herpetiformis
Abstract:
The assembly of membrane attack complex (MAC) of complement implies activation of complement to the attachment of C9 and the presence of MAC on tissue suggests a possible pathogenic role for complement in disease since MAC is able to damage membranes. We examined normal skin of five patients with dermatitis herpetiformis for the presence of MAC using a monoclonal antibody (poly C9-MA) that recognizes a neoantigen of C9 that is not present on monomeric C9 but is common to both isolated MAC and to polymerized C9. Granular deposits of polymerized C9 were found at the sites of IgA deposition in the dermal papillae of normal skin from all patients. The pathologic importance of this finding is uncertain.
Insights
The membrane attack complex (MAC) was found in normal skin of dermatitis herpetiformis patients. These findings suggest a potential role for complement in this skin disease.
Area of Science:
- Immunology
- Dermatology
- Complement System Biology
Background:
- The membrane attack complex (MAC) is the terminal product of the complement cascade.
- MAC assembly involves C9 polymerization and can cause cell membrane damage.
- The presence of MAC in tissues suggests a potential role in inflammatory diseases.
Purpose of the Study:
- To investigate the presence and localization of MAC in normal-appearing skin of dermatitis herpetiformis (DH) patients.
- To determine if MAC deposition correlates with IgA deposits characteristic of DH.
Main Methods:
- Skin biopsies from five DH patients were analyzed.
- Immunohistochemistry was performed using a monoclonal antibody (poly C9-MA) specific for polymerized C9.
- Antibody staining was compared with IgA deposition sites.
Main Results:
- Granular deposits of polymerized C9 were detected in the dermal papillae of all DH patients studied.
- These C9 deposits colocalized with sites of IgA deposition.
- The antibody used specifically recognizes polymerized C9, indicating MAC formation.
Conclusions:
- Polymerized C9, a component of the membrane attack complex, is present in the normal-appearing skin of dermatitis herpetiformis patients.
- MAC deposition occurs at sites of IgA deposition in the dermal papillae.
- The precise pathological significance of MAC in DH remains to be elucidated.