T-helper cell activation in bullous pemphigoid.

In 10 untreated patients suffering from acute bullous pemphigoid the number of peripheral blood T cells (CD 3), T suppressor (CD 8) and T helper cells (CD 4) as well as activation antigens (DR and Tac) bearing lymphocytes was evaluated by monoclonal antibodies. While the pan-T cell population (CD 3) and T suppressor subpopulation (CD 8) were normal, the T helper subpopulation (CD 4) and the number of DR and Tac positive lymphocytes were significantly increased in the acute stage of bullous pemphigoid when compared to the age- and sex-matched controls. Phenotypically those DR positive cells belonged to the pan-T cell population (CD 3) at 66% and to the T helper subpopulation (CD 4) at 53% respectively. Under treatment with immunosuppressants the cell counts returned to normal suggesting a T helper cell activation to be involved in the acute stage of bullous pemphigoid.