Allergic Contact Dermatitis Lesions Research Articles

Detection of Low-Level Tumor Cells in Allergic Contact Dermatitis Induced by Mechlorethamine in Patients with Mycosis Fungoides

Two patients with histologically proven mycosis fungoides, a malignancy of phenotypically mature T cells, received a topical challenge with mechlorethamine to areas of clinically uninvolved skin to exclude possible hypersensitivity reactions to this chemotherapeutic agent. In both patients, allergic contact dermatitis (ACD) developed at the sites of the application and resolved completely after withdrawal of mechlorethamine. The lesions were biopsied and analyzed for the presence of clonal T-cell receptor (TCR)-gamma gene rearrangements using two polymerase chain reaction (PCR)-based assays involving denaturing gradient gel electrophoresis (PCR/DGGE) and ribonuclease protection analysis (PCR/RPA). The former method has a clonal detection threshold of 10(-3)-10(-2), while the latter has a sensitivity of 10(-5). In both cases, the ACD lesions were polyclonal by PCR/DGGE. In contrast, PCR/RPA detected tumor-specific TCR-gamma gene rearrangements in these same lesions. This indicates that the ACD lesions contained tumor cells at a density within the 10(-5)-10(-2) range. Analysis of peripheral blood mononuclear cells from both patients failed to detect the malignant clone and showed the same result as blood from four normal individuals. The normal skin from one skin patient also lacked detectable TCR-gamma gene rearrangements. These results indicate that mycosis fungoides tumor are present within ACD lesions induced in mycosis fungoides patients and that this phenomenon does not appear to be due to the ubiquitous presence of detectable levels of these tumor cells in the blood or skin. These findings might be explained by nonspecific recruitment of malignant T cells to sites of local inflammation mediated by non-neoplastic antigen-specific T cells. Alternatively, they might be due to the local proliferation of very rare tumor cells in apparently normal skin in response to cytokines generated during the ACD reaction. In either case, the present study offers evidence that the malignant cells in myosis fungoides retain at least some capability of responding in vivo to physiologic stimuli.

Overexpression of IL-10 in atopic dermatitis. Contrasting cytokine patterns with delayed-type hypersensitivity reactions.

The skin lesions of patients with atopic dermatitis provide a model to study immunoregulation in human allergy. To determine the local cytokine pattern of cells present (both endogenous and recruited) at the site of disease, we extracted RNA from skin biopsy specimens from patients with atopic dermatitis, allergic contract dermatitis, and positive tuberculin reactions and used PCR to assay for cytokine mRNA. cDNAs were normalized to the intensity of the CD3 delta PCR product as a marker of T cell mRNA. We found overexpression of IL-10 mRNA in atopic dermatitis lesions, in comparison with allergic contact dermatitis lesions and tuberculin reactions. In contrast, IL-4 mRNA was most strongly expressed in allergic contact dermatitis lesions and IFN-gamma mRNA was the predominant cytokine in tuberculin reactions. Using an anti-IL-10 mAb with immunoperoxidase, we localized IL-10 protein to large mononuclear cells in the dermal infiltrate of atopic lesions. After immunomagnetic sorting of mononuclear cell populations from PBMC of atopic dermatitis subjects, IL-10 mRNA as measured by PCR was found to be strongly expressed in CD14+ cells. Spontaneous release of IL-10 from PBMC-derived adherent cells was greater in atopic dermatitis donors than normal controls. We therefore renormalized skin biopsy cDNA according to the level of beta-actin PCR product, as a marker of total cellular mRNA, and found by PCR that IL-10 was nevertheless greatest in atopic dermatitis subjects. We conclude that the relative overexpression of IL-10 in atopic dermatitis greatest in atopic dermatitis subjects. We conclude that the relative overexpression of IL-10 in atopic dermatitis may contribute to the up-regulation of humoral responses and the down-regulation of Th1 responses.

Gamma delta T-cell receptor-positive cells of human skin. II. Appearance in delayed-type hypersensitivity reaction.

In order to investigate the distribution and involvement of human gamma delta T-cell receptor-positive (TCR+) cells in delayed-type hypersensitivity reactions of the skin, we examined the occurrence and kinetics of gamma delta TCR+ cells during skin reactions of allergic contact dermatitis. In normal human skin sections, gamma delta TCR+ cells were scarce. In allergic contact dermatitis from DNCB, increased gamma delta TCR+ cells were observed both in the epidermis and in the dermis from 48 h after the challenge. Most of the gamma delta TCR+ cells were TCR delta 1+ delta TCS1- BB3+ Ti gamma A+ (V delta 1- V delta 2+ V gamma 9+). The percentage of gamma delta TCR+ cells in the peripheral blood remained unchanged and a few gamma delta TCR+ cells in the skin lesions proliferated in situ. It is suggested that the gamma delta TCR+ cells in skin lesions of allergic contact dermatitis may not be involved in initiation of delayed-type hypersensitivity but may have some other roles responding to factors induced in the reaction.

Absence of specific IgE antibodies in allergic contact sensitivity to formaldehyde.

Immunologic reactions are customarily divided into two broad categories, cell-mediated and antibody-mediated. An interplay between these two pathogenetic principles is indicated by reactions such as cutaneous basophil hypersensitivity, late-phase reaction, and cutaneous lesions indistinguishable from regular allergic contact dermatitis lesions after sensitization with IgE antibodies against certain haptens. In the present study, 23 patients with a history of a positive epicutaneous test to formaldehyde participated. On retest, 15 showed a positive reaction. Eight patients were Phadiatop positive, indicating an atopic diathesis, and eight had a history of or ongoing atopic dermatitis. On RAST test, only two, nonatopic patients had specific IgE antibodies to formaldehyde. In the cellular infiltrates of biopsies from epicutaneous test sites, cells reactive with monoclonal antibodies against IgE were found in positive and negative formalin tests, both in atopics and nonatopics, as well as in control biopsies from nonlesional skin. Double immunofluorescence staining experiments showed that IgE occurred on Langerhans' cells. The proportion of IgE-positive cells correlated to the level of serum IgE, but not to atopy. These cells were also found both in the epidermis and in the dermis in nonatopic patients. ICAM-1 occurred on keratinocytes in all patient groups. This study does not support the hypothesis that specific IgE antibodies are active in the pathogenesis of contact sensitivity to formaldehyde either in atopic or in nonatopic patients.

Enrichment and function of urushiol (poison ivy)-specific T lymphocytes in lesions of allergic contact dermatitis to urushiol.

The frequencies of urushiol (poison ivy)-specific T cells were determined in the lesional skin and peripheral blood of patients with allergic contact dermatitis to urushiol. Lesions of urushiol dermatitis were biopsied and the T cells retrieved. Frequencies of Ag-specific cells were determined by limiting dilution assay. Enrichment of urushiol specific T cells was detected in lesional skin or blister fluid of five of five of these donors as well as seven of seven donors with urushiol patch tests. There was also enrichment relative to tetanus toxoid specific T cells in blood and skin of six of seven donors. The frequency of lesional T cells specific for urushiol was less than 1/100 and generally less than 1/1000. Furthermore, the frequency of urushiol specific T cells was often less than 1/10,000 in the peripheral blood during an acute eruption. Autoreactive T cells that proliferated to autologous irradiated PBMC were also enriched in skin lesions relative to blood in 5/5 urushiol patch tests. These autoreactive T cells were expanded and found to be CD4+. It has been proposed that such autoreactive T cells recognize autologous DR and may have a role in immunoregulation. Urushiol-specific T cells were expanded from limiting dilution wells of two donors and characterized. The majority of the urushiol-specific cells were CD8+, and 13/43 lines were suppressive for PWM-induced IgG synthesis.

IgE-positive epidermal Langerhans cells in allergic contact dermatitis lesions provoked in patients with atopic dermatitis

To see whether or not IgE-bearing epidermal Langerhans cells are specific to skin lesions of atopic dermatitis (AD), we performed immunohistochemical and immunoelectron microscopic examinations of dinitro-chlorobenzene (DNCB) contact dermatitis lesions provoked in uninvolved skin of eight patients with AD. In all of the eight examined, IgE-positive epidermal Langerhans cells were observed in the DNCB dermatitis lesions. Typical staining of anti-IgE was absent in the epidermis of normal-appearing skin of five patients with AD. Thus, it is likely that IgE positive epidermal Langerhans cells non-specifically occur in different eczematous diseases provoked in patients with AD.

Ultrastructural studies of allergic contact dermatitis in man. Epidermal cell changes at 3, 6, and 12 h after application of DNCB.

Early epidermal lesions of allergic contact dermatitis were examined by electron microscopy. Normal human volunteers were sensitized to DNCB, and contact reactions were elicited sequentially. Epidermal cell changes at 3 h included: the occurrence of small vacuoles with or without membrane, focal dilatation of intercellular spaces, and the alteration of tonofilaments into short, aggregated bundles. Non-sensitized skin to which DNCB was applied also showed small vacuoles with or without membrane. Monocytes infiltrated into the intercellular spaces which were not dilated, and the neighboring tonofilaments of keratinocytes remained normal.