In-situ T lymphocyte identification in cutaneous tissue sections of benign and malignant dermatoses

Biology of cutaneous squamous cell carcinoma

Nonmelanoma skin cancer is the leading cause of cancer in the United States. Cutaneous squamous cell carcinoma is second only to basal cell carcinoma in prevalence and its incidence is increasing. The biology of squamous cell carcinoma is reviewed under the broad areas of etiology, immunobiology, biochemistry, metastatic potential, and therapy, with emphasis on prevention, diagnosis, and management.

Multicentric reticulohistiocytosis: a report of a case and a review of the pathology

A case of multicentric reticulohistiocytosis (MR) in a 24-yr-old woman is presented. MR is a rare disorder characterized by progressive polyarthropathy and a papulo-nodular skin rash. The diagnosis was established by histological examination of biopsies of erythematous nodules on the fingers which showed circumscribed collections of large mononuclear cells and multinucleate giant cells in the reticular dermis. These were embedded in a fine network of mature fibrous tissue with a scanty lymphocytic infiltrate. Histochemical, immunopathological and ultrastructural investigations confirmed that the large mononuclear cells had the properties of macrophages. The histopathological features of MR are reviewed in the light of current knowledge of macrophage physiology, and evidence for lymphocyte-histiocyte interactions in the pathogenesis of this bizarre granulomatous disorder is presented.

In situ study of T-cell subpopulations in cutaneous T-cell lymphoma. Diagnostic criteria

The T-cell subpopulations present in skin biopsy specimens from 91 patients with cutaneous T-cell lymphoma (CTCL) and from 19 patients with benign lymphocytic infiltrates of the skin were examined in situ to define criteria for the differentiation of benign from malignant lymphocytic infiltrates. The monoclonal antibodies OKT 1 (pan T-cell), BE 3 (pan T-cell), OKT 4 (helper/inducer T-cell), OKT 6 (cortical thymocyte and Langerhans' cell), OKT 8 (suppressor T-cell), and OKT 10 (pan thymocyte) were used in direct or indirect immunoperoxidase reactions. Sections were examined at high magnification, and the distribution and percentage of cells reactive with each antibody were assessed. Three main patterns of staining were observed in the CTCL patients: (1) 64% of the biopsy specimens showed that 60% of the cells present in the dermis were T-cells that were OKT 1+ and BE 3+ and there was an even distribution of the different T-cell subpopulations, with 54% being OKT 4+ and 8% OKT 8+; (2) 21% patients showed selective loss of OKT 1 antigen, and 80% of these also showed loss of BE 3 antigen; and (3) 15% patients showed large numbers of OKT 8+ cells (range, 50%-90%) but the percentages of OKT 1+ and OKT 4+ cells were within the ranges seen in Group 1, indicating the presence of a population of T-cells simultaneously expressing OKT 4 (helper/inducer) and OKT 8 (suppressor) reactivity. In 95% of the CTCL patients, 3.5% OKT 6+ cells were present in the dermal infiltrate, and in 92% of patients, 3% OKT 10+ cells were present. Comparing sections from CTCL and benign dermatoses, no single diagnostic feature was identified, but helpful differentiating features were: (1) the even, rather than nodular, distribution of the T-cell subpopulation; (2) the selective loss of OKT 1 and BE 3 antigens; (3) the presence of T-cells simultaneously expressing OKT 4 and OKT 8 antigens; and (4) the presence of OKT 10+ cells.

Immunocompetent cells in psoriasis. In situ immunophenotyping by monoclonal antibodies

Immunocompetent cells in exacerbating untreated psoriasis vulgaris skin lesions were immunophenotypically studied by the application of a selection of monoclonal antibodies in a two-stage immunoperoxidase technique. Epidermal changes include: focal accumulation of immunoglobulins in the stratum corneum, as demonstrated by a mixture of monoclonal anti-kappa and anti-lambda antibodies; focal accumulation of OKM-1 positive but Mo-2 negative cells high in the epidermis, reflecting granulocytes in Munro's abscesses; a marked decrease in epidermal Langerhans cells with focal abnormal clumping and smaller dendrites, as demonstrated by monoclonal anti-HLA-DR and anti-T6 (OKT-6) antibodies; and, sporadic exocytosis of mainly T1 (Leu-1), T8 (Leu-2a) positive suppressor/cytotoxic T lymphocytes. The dermal infiltrates were found to consist mainly of partically activated T1 (Leu-1), T4 (Leu-3a) positive T-helper/inducer cells with a smaller compartment of T1 (Leu-1), T8 (Leu-2a) positive suppressor/cytotoxic lymphocytes. These cells were found in close apposition to T6 (OKT-6), HLA-DR positive Langerhans cells and further accompanied by a minor compartment of OKM-1, Mo-2 positive monocytes. No B-cells or plasma cells could be demonstrated in the dermis. Natural killer cells were observed only incidentally. These results fit best with the hypothesis that psoriasis is a chronic inflammatory condition as a result of persistent stimulation of T cells by immunogen(s) of epidermal origin.