The role of T lymphocytes and cytokines in the pathogenesis of pemphigoid gestationis

Background: Pemphigoid gestationis (PG), also known as herpes gestationis, is a rare autoantibody-mediated bullous disease, usually associated with pregnancy and the postpartum period. However, infiltrating cells have recently been suggested to also contribute to the pathogenesis of cutaneous lesions. Objectives: To evaluate the immunophenotype of T cells infiltrating the PG lesional skin and their prevalent cutaneous cytokine expression, as well as the presence and distribution of mast cells, eosinophils and neutrophils. Methods: We performed an immunohistochemical study with a large panel of monoclonal antibodies to CD3, CD4, CD8, HLA-DR, CD25, myeloperoxidase, tryptase, eosinophil cationic protein EG2, human interleukin (IL)-2, -4, -5, -8, interferon (IFN)-γ, and granulocyte-macrophage colony-stimulating factor using the alkaline phosphatase-antialkaline phosphatase procedure on lesional skin of seven patients with PG. Skin from four subjects with pruritic urticarial papules and plaques of pregnancy and three additional healthy donors were used as controls. Results: The findings indicate that there is a T-cell population with a prevalent T-helper (Th) 2 phenotype in the lesional skin of PG subjects. We also found a number of eosinophils and neutrophils with clear signs of activation. Conclusions: These data suggest that an inflammatory infiltrate is involved in the production of PG bullous lesions. In particular, we assume that the Th2 cells might be implicated in the very early stages of autoimmune response and may exercise a broad influence in blister formation in this disease.