Lymphocyte subsets and Langerhans cells/indeterminate cells in erythema multiforme

Different in situ distribution patterns of dendritic cells having Langerhans (T6+) and interdigitating (RFD1+) cell immunophenotype in psoriasis, atopic dermatitis, and other inflammatory dermatoses

Dendritic cells bearing Langerhans cell (OKT6+) or interdigitating cell (RFD1+) immunophenotype may be regularly detected within the dermis of chronic skin diseases characterized by a lymphohistiocytic (lymphoreticular) infiltrate. These 2 subsets of antigen-presenting cells within the dermis of lesions of exacerbating chronic plaque psoriasis, exacerbating nummular dermatitis (discoid eczema), atopic dermatitis, allergic contact dermatitis, pityriasis rosea, lichen ruber planus, and cutaneous lupus erythematosus were quantified using computer-assisted morphometry. The mean dendrite length per dermal dendritic cell was significantly higher for RFD1 than for OKT6 (74.4 +/- 0.98 microns vs 70.0 +/- 1.26 microns: p = 0.0023). The mean dendrite length per dermal dendritic cell was remarkably constant for each marker in the various diagnostic categories studied. Disease-specific patterns of total dendrite length and number (expressed per 100 infiltrating mononuclear cells) of these 2 dendritic cell types within the subepidermal infiltrates were obtained. Pityriasis rosea was characterized by its unique high percentage of OKT6+ Langerhans cells. Atopic dermatitis and psoriasis had relatively high percentages of both RFD1+ interdigitating cells and OKT6+ Langerhans cells. Nummular dermatitis had an intermediate number and total dendrite length for OKT6, but was relatively low in RFD1+ cells. Allergic contact dermatitis, lichen planus, and lupus erythematosus had low numbers and dendrite lengths for both dendritic cell subsets. It is suggested that pityriasis rosea is characterized by an abnormal migration pattern of Langerhans cells. Psoriasis and atopic dermatitis may be examples of diseases in which skin-localized antigen-presenting and T-cell-inducing events are continuously taking place. The other diseases may reflect inflammatory processes in which local antigen presentation is less relevant to the tissue reaction.

Erythema multiforme in a patient with T cell chronic lymphocytic leukemia

A patient with T4+ (helper-inducer) T cell chronic lymphocytic leukemia developed an erythema multiforme-like eruption, the diagnosis of which was supported by routine light microscopic findings. Immunopathologic studies using monoclonal antibodies demonstrate that despite an overwhelming majority of leukemic T4+ cells in the peripheral blood and dermal infiltrate, the predominant cells in the epidermal infiltrate are T8+ (cytotoxic-suppressor) cells. These findings are different from those seen in epidermotropic T cell leukemic infiltrates and are similar to those previously reported in erythema multiforme. Thus it is likely that the leukemic T4+ cells are participating in this cutaneous hypersensitivity reaction along with residual, normal T8+ cells.

Immunohistochemical staining of Langerhans cells and macrophages in oral lichen planus

Twenty patients with clinically and microscopically confirmed lichen planus were studied immunohistochemically. Monoclonal antibody to HLA-DR antigens and polyclonal antisera to S-100 protein and muramidase were applied to paraffin-embedded sections for the purpose of elaborating on the pathogenesis of this disease. Trypsin incubation of sections was also done in order to determine its effect on immunostaining. Langerhans cells were identified with anti-S-100 and anti-HLA-DR, and macrophages were identified with antimuramidase and anti-HLA-DR. Keratinocytes also expressed HLA-DR membrane activity in lichen planus tissue. Trypsinization significantly improved the expression of S-100 protein and muramidase antigens. It was concluded that Langerhans cells, macrophages, and keratinocytes play important roles in antigen processing and/or phagocytosis during the natural history of this disease.

Langerhans cells in human papillomavirus (HPV) lesions of the uterine cervix identified by the monoclonal antibody OKT-6

The local inflammatory cell infiltrates in 263 cervical punch biopsies of the women followed-up since 1981 (16 +/- 14 months, mean +/- S.D.) for an established human papillomavirus (HPV) lesion with or without concomitant cervical intraepithelial neoplasia (CIN) were analysed for occurrence of Langerhans cells, defined by the monoclonal antibody OKT-6 using the avidin-biotin peroxidase complex (ABC) technique. OKT-6+ cells remained at the constant low level (1.5-1.9% of the inflammatory cells) in the different types of HPV lesions (flat, inverted or papillomatous condylomas), their percentages (range 0.8-2.1% of the cells) being slightly affected by the grade of HPV-associated CIN, however, (P less than 0.05 between HPV-CIN I and HPV-CIS). Although cervical HPV lesions characteristically are a disease of young females, the relative levels of in situ Langerhans cells did not show any age-dependence. Furthermore, the intensity of the inflammatory cell infiltrate did not correlate with the relative levels of OKT-6+ cells in the biopsies. Practically identical (1.6%) levels of OKT-6+ cells were found in the first biopsies of the HPV lesions shown to regress during the follow-up period (28.8% of cases), when compared with those (1.7%) in the lesions persisted (52.1% of cases) or progressed (19.1% of lesions). The results are discussed in terms of the proposed immune surveillance function against viral infections, attributed to Langerhans cells in the SALT/MALT concept.(ABSTRACT TRUNCATED AT 250 WORDS)