Background: Eosinophil and polymorphonuclear granulocytes may be involved in the formation of blisters in bullous dermatoses, particularly bullous pemphigoid.

Objective: Our purpose was to evaluate the role of granulocyte activation in the pathogenesis of pemphigus vulgaris and bullous pemphigoid.

Methods: Levels of eosinophil cationic protein (ECP) and neutrophil-derived myeloperoxidase (MPO) in blister fluid and serum and levels of serum IgE were determined in patients with bullous pemphigoid (n = 12), those with pemphigus vulgaris (n = 9) and healthy volunteers (n = 12).

Results: In blister fluid and serum of patients with bullous pemphigoid, significantly elevated concentrations of ECP, MPO and IgE were detected as compared with controls. In contrast, ECP, MPO, and IgE levels in blister fluid and serum of patients with pemphigus vulgaris did not significantly differ from controls. Moreover, the MPO/ECP ratio in serum of patients with bullous pemphigoid was significantly decreased as compared with controls, whereas the MPO/ECP ratio in pemphigus vulgaris did not differ from controls, indicating a preferential activation of eosinophils in bullous pemphigoid only. In patients with bullous pemphigoid, serum levels of ECP and MPO significantly decreased during immunosuppressive therapy to levels similar to those of controls.

Conclusion: Activated granulocytes, releasing their granular contents such as ECP and MPO, may be of importance for blister formation in bullous pemphigoid and may be useful for monitoring disease activity.