T-Cell Subsets in Acne rosacea Lesions and the Possible Role of <i>Demodex folliculorum</i>

Abstract

Skin biopsy specimens from 4 patients with typical acne rosacea lesions were examined for the presence of T-cell subsets using monoclonal antibodies. The infiltrates consisted chiefly of LEU-1 reactive T cells with a predominance of LEU-3a antibody positive helper-inducer T cells, while LEU-2a staining suppressor-cytotoxic T cells were scarce. These cells penetrated regularly into the follicular wall and the epidermis. The study showed that most T cells in the dermal granulomatous infiltrates around Demodex parts, which were displaced extrafoUicularly, were helper-inducer T cells. The predominance of helper-inducer T-cell subsets in the dermal infiltrates of acne rosacea lesions in frequent association with Demodex supports the hypothesis that a cell-mediated immune response plays an important role in the pathogenesis of rosacea.

Rosacea: An Update

“…In a histologic study of 53 patients with granulomatous rosacea, Demodex was present in 9 biopsy specimens [31]. Rufli and Buechner [32]detected a helper T-cell infiltrate in the dermal granulomatous infiltrates around Demodex parts. Histologic and immunohistochemical examination of biopsy specimens from patients with rosacea revealed a dense perifollicular infiltrate of predominantly CD4 T cells [28].…”

Demodicidosis Mimicking Granulomatous Rosacea and Transient Acantholytic Dermatosis (Grover’s Disease)

“…Nor mally, not more than 2 mites can be demon strated in one follicle [1]. Heavy attacks of D. folliculorum may lead to [13]: (a) mild to moderate dense perifollicular lymphohistiocytic infiltrates without typical clinical manifestations; (b) dense inflammatory in filtrates with invasion of polymorphous nuclear leukocytes into the follicle epitheli um clinically resembling rosacea-like le sions, and (c) lymphocytic or epitheloid cell granulomas surrounding extrafollicular mites, clinically corresponding to parafollic ular inflammatory papules.…”

“…Furthermore, specific immunological reactions seem to be important in the development of the clinical picture. It could be demonstrated that a dense T-helper population is present perifollicularly in Dcmodex-rich rosacea lesions [13]. Additionally, in serum of patients suffering from rosacea, a significantly higher incidence of specific antibodies against Demodexcaprae can be demonstrat ed [20].…”

Rosacea: Disease or Reaction Pattern?

“…The passive migration of an acarian antigen or an acarus from the folli cle is of course possible [6]. In this respect, the predominance of T helper inducer cells [19] in the infiltrates and the presence of precipitating antibodies with extracts of an tigen of Demodex caprae in 4 out of 18 pa tients suffering from rosacea may suggest that an immunologic process against the Demodex plays an important part. Antibod ies directed against Demodex may crossreact to nuclei of dermal cells [15].…”