Ultrastructural aspects of equine pemphigus foliaceus-like dermatitis. Report of cases.

The research article explores the micro-structural abnormalities seen in horses affected by pemphigus foliaceus-like skin conditions. The findings suggest these conditions share similarities with human, calf, and guinea pig versions of the disease, including cellular disruption, bacterial invasion, and alterations in cellular metabolism which may contribute to the development of skin lesions.

Understanding Equine Pemphigus Foliaceus-like Dermatitis

Pemphigus foliaceus is a rare skin disorder that can occur in several species, including horses. The study focuses on the ultrastructural alterations of the horse’s skin affected by this disease. The early cellular signs of the disease demonstrate characteristics similar to the human, calve, and guinea pig versions of pemphigus foliaceus.

• Prior to the complete breakdown of cells (acantholysis) and the formation of fluid-filled blisters (bullae), the spaces between cells increased, but cellular structures that provide adhesion (desmosomes) remained intact.
• An unusual observation was the presence of clusters of densely packed granular substances in the spaces between cells in the outermost layer of the skin (epidermis). These could represent autoantibodies, or misshapen binding substances.

Pre-Clinical Changes and Lesion Formation

The team also documented other changes before acantholysis.

• This included mild distortion (dyskeratosis), decreased peripheral tonofilaments (protein structures inside cells), enlargement of rough endoplasmic reticula (a cell organelle that helps produce proteins), and cell damage signaled by the formation of vacuoles and mitochondrial damage.
• In more serious lesions where bullae were present, the researchers found evidence of bacterial infiltration and white blood cell invasion in all layers of the skin.

Similarities to Autoimmune Disorders

The abnormalities observed in horses suggest that equine pemphigus foliaceus is morphologically similar to pemphigus autoimmune disorders seen in other species.

• These changes can point to cellular metabolic disorders that potentially occur simultaneously with the events leading to acantholysis and bullae formation.
• The research provides morphological evidence supporting the idea that some cellular metabolic disruptions might occur alongside the extracellular changes that precede cell disruption and lesion formation.