[Immune phenotyping of mononuclear infiltrate in bullous pemphigoid]

In bullous pemphigoid, autoantibodies alone are not capable of blister formation. In addition, they need complement and various inflammatory cells. The role of mononuclear cells, however, is poorly understood. Therefore, we studied the inflammatory infiltrate in 21 patients with bullous pemphigoid and 11 controls (normal skin, n = 5; eczematous skin, n = 6) using a panel of monoclonal antibodies. In bullous pemphigoid, 60% of the mononuclear infiltrate consists of CD3+ T-lymphocytes, while 25% represents monocytes/macrophages (MOMA); B-lymphocytes are absent. In the area of the basement zone (BMZ), which was studied separately, MOMA predominate. In 30% of bullous pemphigoid biopsies we found a close, almost linear attachment of MOMA to the BMZ. Along the BMZ, lymphocytes belong to the CD3+, CD4+ T-helper subset. CD8+ T-cytotoxic-suppressor cells, however, are rarely encountered there, and other cytotoxic lymphocytes are not found at all. All lymphocytes along the BMZ are memory cells. In small, early bullous pemphigoid lesions, MOMA are frequently the only effector cells. Eosinophilic granulocytes are rare in these lesions. Our findings suggest that mononuclear cells, and particularly MOMA, may be more important than believed hitherto in the inflammatory process resulting in separation of the BMZ.