Immunocompetent and accessory cells in dermatitis herpetiformis.

Area of Science:

• Immunology
• Dermatology
• Pathology

Background:

• Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin disease.
• Understanding the cellular infiltrate in DH lesions is crucial for elucidating disease pathogenesis.

Purpose of the Study:

• To investigate the lymphocyte subsets in peripheral blood and skin lesions of patients with dermatitis herpetiformis.
• To analyze the kinetics and cellular composition of the early inflammatory response in potassium iodide (KI)-induced DH lesions.

Main Methods:

• Monoclonal antibodies and immuno-histochemical methods (biotin-avidin immunolectin, indirect immunofluorescence) were used.
• Lymphocyte subsets (T3, T4, T8) were quantified in peripheral blood and lesional skin.
• Kinetics of early inflammatory cells (peroxidase-positive, Ia-positive) were studied in pre-blister stages.

Main Results:

• Peripheral blood lymphocyte subsets in DH patients did not differ significantly from healthy controls.
• Mature DH skin lesions showed a dominance of T3-positive lymphocytes (82%).
• T4-positive lymphocytes were significantly higher in DH skin lesions (63%) compared to peripheral blood (48%), indicating selective infiltration.
• Early inflammatory response (6 hours post-induction) revealed peroxidase-positive cells and Ia-positive, peroxidase-negative cells, suggesting early pathogenetic events.

Conclusions:

• The dermal infiltrate in DH lesions is not a nonselective trapping of blood cells but reflects a specific inflammatory response.
• T-lymphocyte dominance, particularly T4-positive cells, characterizes mature DH skin lesions.
• Early cellular events involving proteinases and Ia-positive cells may play a significant role in DH pathogenesis.