Enzyme-antienzyme method for immunohistochemistry.

Immunohistochemical stains use antibodies to identify specific constituents in tissue sections. In order to detect the site of reaction, the antibody is labeled with an enzyme that can be reacted with a suitable substrate to give a colored product. The alternative is to use a fluorescent label. The advantage of an enzyme label is that the nuclei can be counterstained, thereby revealing the tissue architecture, and that the stain fades slowly, if at all, with time, allowing the slides to be stored.

Enzyme-antienzyme method for immunohistochemistry.

Immunohistochemical stains use antibodies to identify specific constituents in tissue sections. In order to detect the site of reaction, the antibody is labeled with an enzyme that can be reacted with a suitable substrate to give a colored product. The alternative is to use a fluorescent label. The advantage of an enzyme label is that the nuclei can be counterstained, thereby revealing the tissue architecture, and that the stain fades slowly, if at all, with time, allowing the slides to be stored.

Detailed investigation of the diagnostic value in tumour histopathology of ICR.2, a new monoclonal antibody to epithelial membrane antigen.

The production and detailed immunostaining properties of a new rat monoclonal antibody (ICR.2) to epithelial membrane antigen are reported. The antibody was selected for its ability to compete with the polyclonal antiserum (M7), used in the original immunohistological studies, in order that it might serve as a direct replacement in diagnosing epithelial tumours. Most of the staining reactions on normal tissues were identical to those previously reported with M7 but there were some important differences. They included: positivity of renal and adrenal capsular fibroblasts, perineurium, some myoepithelial and smooth muscle cells, occasional osteoblasts and squamous and thyroid follicular epithelium in the normal state. The intercellular canaliculi of sweat glands and secretory canaliculi of gastric oxyntic cells were clearly demonstrated. These staining reactions could be obtained with M7 when a sensitive detection system was used although the results were usually weak and inconsistent. Nearly all adenosquamous and transitional carcinomas were positive. The remaining tumours fell into three major groups: (1) those which were consistently or nearly consistently negative--melanoma, seminoma, rhabdomyosarcoma, alveolar soft part sarcoma, adrenal cortical carcinoma, granulocytic sarcoma, paraganglioma, non-Hodgkin's lymphoma. Hodgkin's disease and embryonal carcinoma: (2) those which were either negative or positive with distinctive patterns of staining--basal cell carcinoma, embryonal tumours: and (3) non-epithelial tumours that were consistently positive--epithelioid sarcoma, synovial sarcoma, osteosarcoma, chordoma and myeloma--or positive in a significant minority of cases--leiomyosarcoma, malignant fibrous histiocytoma, clear cell sarcoma of tendon sheath, various neuroectodermal tumours.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistology of the thymus in bone marrow transplant recipients.

The immunohistological findings in the thymus after bone marrow transplantation were studied in autopsy samples from 12 patients who had received allogeneic grafts as treatment for acute leukemia. The findings were compared with those in samples from normal individuals and from conventionally treated leukemic patients. The thymuses were hyperinvoluted in all grafted and nongrafted subjects. The remnants were composed of subcapsular and medullary epithelium which expressed the same phenotype as the normal thymus controls. Most samples also contained small remnants of cortical epithelium which lacked normal expression of HLA-DR antigens. The intraepithelial and stromal thymic lymphocytes were virtually all mature T cells, and no immature cortical thymocytes were seen. With the use of HLA-typing methods in 2 recipients of one-haplotype-matched grafts no donor cells could be identified in any of the thymic components. These findings provide no evidence for a functional role for the thymus in the differentiation of donor-derived precursor T cells, at least in the early period after transplantation.

Chimerism in skin of bone marrow transplant recipients.

Skin biopsies from 3 patients receiving one-haplotype-matched bone marrow grafts have provided a unique opportunity to demonstrate the presence of donor cells in situ using immunohistological techniques and a monoclonal antibody directed against an epitope common to HLA-A2 and HLA-A28 antigens. The infiltrating cells were also analyzed in consecutive tissue sections with a panel of monoclonal antibodies to human leukocyte antigens, T cells, and epidermal Langerhans cells. Most of the infiltrating cells were shown to be T lymphocytes of donor origin, regardless of whether the histological changes were consistant with graft-versus-host disease (GVHD) or were eczematous. Donor T cells were also shown to colonize histologically normal skin soon after transplantation. Epidermal keratinocytes, dermal endothelium, and adnexal structures did not express the donor HLA type (i.e., were host derived) but the origin of the epidermal Langerhans cells could not clearly be established. The data show that donor cells preferentially migrate to certain sites in skin after transplantation and are not always associated with GVHD.

Morphological and immunohistological changes in the skin in allogeneic bone marrow recipients.

Skin biopsies from leukaemic patients undergoing allogeneic bone marrow transplantations and treated prophylactically with cyclosporin A were analysed using histological, morphometric, and immunohistological techniques. Samples from donors were used to establish normal values. Biopsies taken from recipients two days before grafting were all histologically normal, but on immunohistological staining half of them showed a reduction in the number of epidermal Langerhans' cells and 29% a reduction in T inducer lymphocytes. Thirty two biopsies were taken from patients with rashes at various times after transplantation: 14 showed lichenoid changes consistent with graft versus host disease, three eczematous tissue reactions, two vesicular lesions, and 12 no histological abnormality. One sample showed changes intermediate between the lichenoid and eczematous forms. The numbers of epidermal Langerhans' cells were low during the first few weeks after transplantation and were normal or raised later regardless of histological appearances. Unlike epidermal Langerhans' cells, significant reductions in the numbers of lymphocytes were not seen. Lesions of all histological types contained mixtures of T inducer and T suppressor/cytotoxic cells, although the eczematous and vesicular lesions contained higher proportions of T inducer cells. Epidermal infiltrates invariably contained T suppressor/cytotoxic cells but infiltration of epidermis by T inducer cells occurred only in the presence of normal numbers of epidermal Langerhans' cells. Natural killer cells were not identified. The immunological appearances of the various histological subgroups thus change with time after transplantation.

Detection of micrometastases in patients with primary breast cancer.

An immunocytochemical method was used to screen smears obtained at primary surgery from multiple bone-marrow sites in 110 patients with breast cancer; at this time other techniques did not reveal metastases. Tumour cells were detected in the bone-marrow of 31 (28%) patients. The number of cells detected ranged from 1 to greater than 500; none was detected in conventionally stained smears. Patients in whom conventional criteria indicated a very poor prognosis seemed more likely to have such micrometastases. A further follow-up period is required to determine whether patients with micrometastases relapse earlier than those in whom no tumour cells are demonstrable.

Comparative functional histopathology of human breast carcinoma xenografts.

A series of xenografts of human breast carcinomas has been established and serially transplanted in immune-suppressed mice. Certain structural and functional features of the original human tumours, including carcinoembryonic antigen and epithelial membrane antigen, continue to be expressed by the resulting xenografts. Stromal responses such as elastosis and oestrogen-receptor activity were lost by the xenografts. No metastases were detected in tumour-bearing mice. This study suggests that xenografts may have some value in experimental pathology as one type of model of human breast carcinoma.

The use of antisera to epithelial membrane antigen in detecting micrometastases in histological sections.

We have investigated, by immunocytochemical means, the value of an antiserum raised to milk-fat-globule membranes in detecting metastatic deposits of breast carcinoma in conventional histological sections of liver, lymph nodes and marrow. The antiseum recognizes a membrane component, which we have called Epithelial Membrane Antigen, and which is confined to but widely distributed in epithelial tissues and tumours derived from them. In the sections examined, a greater extent of tumour infiltration was usually found, largely due to the identification of single malignant cells which normally go unrecognized with conventional stains. The number of positive samples was only increased, however, in sections of marrow aspirates, and the reasons for this are discussed. We suggest that further increases in detection rates could be attained by using the antiserum on cytological smears of marrow or even in cell suspensions.