Intralesional T lymphocyte phenotypes and HLA-DR expression in Melkersson-Rosenthal syndrome

An immunohistochemical double-staining technique was used to characterize the infiltrating mononuclear lymphocytes in frozen sections from 3 patients with Melkersson-Rosenthal syndrome. The in situ expression of HLA-DR antigens on different cell types was also investigated. The majority of mononuclear cells could be classified as T-lymphocytes because of their Leu 4 antigen expression. Most of the T-lymphocytes were confined to the helper/inducer lymphocyte subset since they reacted with Leu 3a antibodies. However, big infiltrates of suppressor/cytotoxic lymphocytes with the Leu 2a phenotype were noted in some specimens. These cells were situated between the ducts of the salivary glands. Virtually all mononuclear infiltrating cells carried HLA-DR antigens. HLA-DR expressing keratinocytes were found in the biopsy from one patient. The present study indicates that a local immune response may be important in the pathogenesis of the oro-facial lesions in Melkersson-Rosenthal syndrome.