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Herpes gestationis: ultrastructural identification of the extracellular antigenic sites in diseased skin using
Insights
Herpes gestationis involves immune complex deposition and cleavage at the skin basement membrane, specifically the sub-basal dense plate and hemidesmosomes. This finding links herpes gestationis to bullous pemphigoid pathogenesis.
Area of Science:
- Dermatology
- Immunology
- Pathology
Background:
- Herpes gestationis is an autoimmune blistering disease.
- Understanding the precise location of immune events is crucial for disease pathogenesis.
Purpose of the Study:
- To investigate the level of immunological events in the skin basement membrane during herpes gestationis blister formation.
- To elucidate the relationship between herpes gestationis and bullous pemphigoid.
Main Methods:
- Direct immunogold technique was used to study IgG and C3 deposition.
- Skin basement membrane ultrastructure was examined during blister formation.
Main Results:
- IgG and C3 were localized in the lamina lucida, above the lamina densa.
- Cleavage occurred at the sub-basal dense plate, involving immunocomplex aggregates.
- Upper hemidesmosomal structures were also implicated in the cleavage process.
Conclusions:
- Cleavage in herpes gestationis occurs at the sub-basal dense plate, with parallel cleavage through hemidesmosomes.
- These findings support the involvement of hemidesmosomes in herpes gestationis pathogenesis.
- The study highlights a potential link between herpes gestationis and bullous pemphigoid.
Abstract:
Using a direct immunogold technique, we studied the level of immunological events in the skin basement membrane in a patient with herpes gestationis during blister formation. Within the lamina lucida, IgG and C3 were localized beneath the basement membrane of basal keratinocytes, 30-40 nm above the lamina densa. In many areas of blister formation sub-basal dense plates, but probably also the upper parts of the hemidesmosomes were separated from the roof of the blister. In the perilesional lamina lucida and in the blister, IgG and C3 containing amorphous grains, most probably immunocomplex aggregates, were detected. They covered the basement membrane of keratinocytes and left free a 30-40 nm band above the lamina densa. Our study indicates that in herpes gestationis the cleavage, accompanied by IgG, C3 and immunocomplex deposition, occurs at the level of the sub-basal dense plate. However, cleavage through upper hemidesmosomal structures can occur in parallel. These data further support the involvement of hemidesmosomes in the pathogenesis of the disease and therefore in its relationship to bullous pemphigoid.