Immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes)

Cytogenetic and immunohistochemical analysis of lymphoepithelioid cell lymphoma (Lennert's lymphoma): further substantiation of its T-cell nature

In 1968 a special variant of Hodgkin's disease, epithelioid cellular lymphogranulomatosis--later on termed lymphoepithelioid cell lymphoma/Lennert's lymphoma--was defined. There are increasing indicators that Lennert's lymphoma is of T-cell origin. Seven cases of Lennert's lymphoma are studied with cytogenetic as well as immunohistochemical techniques. Six of them have cytogenetic abnormal clones always including aberrations of chromosome No. 3 (+3, break in q22, dup q22----q24). In all cases band 3q22 is either broken or duplicated. Immunohistochemically it is clearly demonstrated that the proliferating cells are of T-cell nature (Ki67+, Leu4+, Leu1+). Under consideration in the literature it can be stated in conclusion that (1) lymphoepithelioid cell lymphoma (Lennert's lymphoma) with aberrations has to be designated as malignant lymphoma, (2) immunohistochemical double labeling proved the T-cell nature of this lymphoma, (3) there are remarkable similarities between the chromosomal patterns of lymphoepithelioid cell lymphoma, lymphogranulomatosis X/angioimmunoblastic lymphadenopathy and probably Hodgkin's disease: many normal mitoses and abnormalities of chromosome No. 3, especially trisomy. It is discussed that abnormalities of chromosome No. 3 involving band q22 are an indicator of a common genetic background of these lymphomas.

Monoclonal antibody specific to acid phosphatase isoenzyme 4

Prostatic acid phosphatase isoenzyme 4 was purified by ion exchange column chromatography, followed by high pressure liquid chromatography. The highly purified enzyme was used to produce monoclonal antibody from immunized BALB/c mice. The antibody was specific to isoenzyme 4, with negligible affinity to isoenzyme 2. The specificity of the monoclonal antibody was evaluated by Western blot analysis and by inhibition of radioimmunoassay. Immunohistochemistry method using the antibody to isoenzyme 2 showed heavy staining on the cell surface in contrast to the even staining throughout the cytoplasm when monoclonal anti-isoenzyme 4 was used. These results reflect the secretory nature of isoenzyme 2 and the non-secretory nature of isoenzyme 4.

An immunocytochemical study of malignant melanoma and its differential diagnosis from other malignant tumours

A series of 41 fresh and 36 routinely processed malignant melanomas were immunostained with a panel of 12 monoclonal antibodies reactive against a range of epithelial, lymphoid, and melanoma associated antigens. The aim of the study was to determine whether this panel of antibodies would be useful in diagnostically difficult cases for differentiating melanomas from other tumours, particularly carcinomas and lymphomas. The results confirmed that most unequivocal malignant melanomas can be identified by positivity for S100 protein and for the antigen recognised by antibody NK1/C3, and by negativity for epithelial and lymphoid antigens. The incidence of melanomas expressing cytokeratin antigens was higher, however, particularly in cryostat sections than has previously been reported. It is therefore suggested that a panel of antibodies with more than one marker in each category should be used for identifying melanomas in clinical practice.

Double staining immunofluorescence procedure for enumeration of cells containing cytoplasmic immunoglobulin in human bone marrow: 40 selected cases

A double staining immunofluorescence method was developed that allowed the reliable differential counting of cells containing cytoplasmic immunoglobulin in human bone marrow. These cells were stained with a polyspecific antihuman immunoglobulin serum conjugated with rhodamine. In separate preparations subpopulations of cells containing each heavy chain class and light chain type were identified by prior staining with isotype specific fluorescein conjugated antihuman immunoglobulin sera. A standardised counting procedure was adopted to indicate the degree of plasma cell infiltration and to establish the percentage of cells containing each type of immunoglobulin. A series of 122 patients requiring haematological investigation of the bone marrow for various disorders but without evidence of paraproteinaemia was tested to provide results for a nonmyelomatous reference group. These results were compared with those from 40 patients with paraproteins of various classes in their serum. The procedure described here clearly differentiated the two groups. When combined with serum paraprotein assays and conventional haematological cytology of bone marrow these counts provided useful additional information in cases of diagnostic difficulty and in the assessment of individual patients before, during, and after treatment.

Production of monoclonal antibodies against human epithelial membrane antigen for use in diagnostic immunocytochemistry

Two monoclonal murine antibodies have been raised against a delipidated extract of human cream. These antibodies were detected by immunohistological screening of hybridoma culture supernatants on sections of human breast tissue. One of those antibodies (E29) was subsequently screened against a range of normal and neoplastic human tissues and shown to react with a wide variety of human epithelia and with mesothelial cells. Antibody E29 was unreactive with other cell types, with the exception of occasional plasma cells. Antibody E29 is suitable for use on paraffin embedded tissue and represents a valuable reagent for the identification of tumours of epithelial origin.

Detection of metastatic tumour cells in routine bone marrow smears by immuno-alkaline phosphatase labelling with monoclonal antibodies

The present study describes 11 cases (10 carcinomas, one rhabdomyosarcoma) in which immuno-alkaline phosphatase labelling with monoclonal antibodies was used to demonstrate metastatic cells in routine smears of aspirated bone marrow. Carcinoma cells were detected using antibodies against epithelial cytokeratins, milk fat globule membrane antigen and carcinoembryonic antigen, and rhabdomyosarcoma cells with monoclonal anti-desmin. In four of the carcinoma cases it had not been possible to identify malignant cells in routinely stained marrow smears, whilst the case of disseminated rhabdomyosarcoma had initially been diagnosed (and treated) as a case of acute lymphoblastic leukaemia. The anti-cytokeratin antibody was found to be the most valuable of the anti-epithelial reagents used, since it labelled malignant cells in all of the 10 cases of carcinoma and gave the strongest reactions. These results suggest that immunocytochemical labelling should be used in cases of suspected carcinoma whenever conventional examination of marrow smears yields negative results, and furthermore (as illustrated by the case of rhabdomyosarcoma) that the technique is of value for identifying the true nature of poorly differentiated neoplasms in bone marrow.

Human lung tumours: a correlation of antigenic profile with histological type

Fifty-four human lung tumours have been immunostained with a large panel of monoclonal antibodies including reagents against cytokeratins, prekeratins, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA) and neural antigens. These results have been compared with the histological types of tumour using the current WHO classification scheme. The most striking finding of this study was the considerable overlap of antigenic profile between different histological types of tumour. This suggests that there may be a greater underlying similarity between different histological categories of lung tumour than has hitherto been assumed. Secondly it was evident that immunostaining highlighted areas of different morphology within many tumours emphasizing the heterogeneous differentiation patterns seen in lung cancers. The present study supports the viewpoint that lung tumours arise from a common stem cell and that these neoplasms represent a single tumour with a tendency to differentiate along one or more pathways.

Role of immunohistochemistry in diagnosis of nasopharyngeal tumours

To evaluate the usefulness of immunocytochemistry in the differential diagnosis of nasopharyngeal tumours, 35 undifferentiated nasal carcinomas were examined with a panel of monoclonal antibodies against a wide variety of epithelial and non-epithelial antigens. The results were compared with those obtained from a series of nasopharyngeal tumours comprising three squamous cell carcinomas, six lymphomas, one rhabdomyosarcoma, and one yolk sac tumour. All of the carcinomas were positive with at least one of the antiepithelial markers and negative for the leucocyte common antigen and were clearly distinguishable from the nasopharyngeal lymphomas, which gave the opposite staining pattern. It was concluded that such a panel of monoclonal antibodies would be extremely useful for the differential diagnosis of nasopharyngeal tumours, particularly with small or technically inadequate biopsies.

The value of immunocytochemical methods in the differential diagnosis of anaplastic thyroid tumours

The practical usefulness of a panel of monoclonal antibodies recognising epithelial and lymphoid antigens has been evaluated on a series of 10 routinely processed thyroid tumours of uncertain origin. All 6 small cell tumours were shown to be of lymphoid origin whereas of the 4 large cell tumours two were lymphomas and two carcinomas. Two of the tumours, one large cell and one small cell, were undiagnosable due to technical reasons (crush artefact or small size of biopsy) and emphasized the value of immunohistology in this context. Clinical follow-up of all 10 cases indicated that these distinctions are of both prognostic and therapeutic value. It is concluded that immunocytochemistry using a carefully selected panel of monoclonal antibodies is a valuable and convenient means of making an objective distinction between anaplastic thyroid tumours of epithelial or lymphoid origin.

Immunocytochemical staining of T and B lymphocytes in serous effusions

Cell smears from serous effusions containing large numbers of lymphoid cells were stained by the alkaline phosphatase-anti-alkaline phosphatase technique with a panel of monoclonal antibodies, including anti-B and anti-T cell antibodies and anti-HLA-DR. Samples from 17 patients with lymphoproliferative disorders--such as chronic lymphocytic leukaemia and non-Hodgkin's lymphoma--and from 19 patients who had no evidence of lymphoid neoplasia--for example, cases of carcinoma, cardiac failure--were investigated. The majority of lymphoid cells in reactive effusions were T cells, which lacked HLA-DR and showed a marked excess of helper/inducer cells (mean helper to suppressor ratio of 3 X 5). In contrast, lymphoid cells in samples from nine cases of B cell neoplasia were positive for B cell antigen and HLA-DR. In a further four B cell neoplasms most lymphoid cells were reactive T cells. Two cases of T cell lymphoid leukaemia could also be characterised by immunocytochemical staining, both being classified as T helper cell neoplasms. Labelling was performed on routinely prepared, air dried cell smears, which could be stored in the unfixed state for long periods before staining. The technique may therefore be of use in many clinical cytology laboratories for the diagnosis of effusions containing numerous lymphoid cells.

Modified immunocytochemical slide technique for demonstrating surface antigens on viable cells

Further developments of an immunoenzymatic slide technique to demonstrate cell surface antigens with monoclonal antibodies are described. In this method cells are attached to polylysine coated glass slides in order to facilitate the handling of low cell numbers and to save antibodies and time for washing the cells. The technique has been modified for the labelling of viable cells. Endogenous peroxidase is used as an additional cell marker which does not interfere with the demonstration of antigens on the cell surface by immunoperoxidase methods. Damaged cells can be identified reliably, thereby minimising interpretation errors due to non-specific antibody uptake. A double labelling technique employing peroxidase and alkaline phosphatase coupled reagents is presented. Results of this slide technique are clear cut, so that evaluation can be performed by trained technicians.

An alkaline-phosphatase staining method in avidin-biotin immunohistochemistry

An avidin-biotin alkaline-phosphatase (ABAP) staining method has been developed for the labeling of tissue sections and cell smears. The introduction of alkaline phosphatase as a marker enzyme through an avidin bridge results in excellent immunocytochemical labeling of different antigens using poly- and monoclonal antibodies. This technique avoids problems with endogenous peroxidase activity that sometimes occur using peroxidase staining procedures. The introduction of a preformed avidin-biotin alkaline-phosphatase complex (ABAPC) makes the presented technique as simple to handle as the widely used avidin biotin-peroxidase complex method (ABC). The ABAPC technique could be combined with other enzymatic labelings for double immunoenzymatic staining.

Sézary syndrome: phenotypic and functional characterization of the neoplastic cells

Phenotypic properties of the neoplastic cells in skin, blood and lymph node specimens from 5 patients with the Sézary syndrome were examined by immuno-enzymatic and -fluorescence labelling of cells and tissue sections with a monoclonal antibody panel. In 3 cases, the in vitro functional properties of the neoplastic cells (isolated from blood specimens) were also analysed using a reverse plaque-forming cell assay. 3 different immunological categories were identified as follows: T-helper/inducer neoplasms (3 patients); T-suppressor/cytotoxic neoplasms (1 patient); and neoplastic T-cells demonstrating characteristics consistent with a concept of their derivation from inducible suppressor T-cells (1 patient). These data provide conclusive evidence that Sézary syndrome is heterogeneous with respect to the immunological characteristics of the neoplastic cells.

Phenotypic analysis of an established cell line derived from a patient with Hodgkin's disease (HD)

This report describes the phenotypic analysis of a cell line obtained from a female patient with the nodular sclerosing subtype of Hodgkin's disease (HD). The cell line has a neoplastic karyotype and is stable in culture in the absence of feeder layers or growth factors. Phenotypic analysis of this cell line shows that it cannot easily be characterized as either a lymphocyte, macrophage or granulocyte but resembles in its characteristics certain HD lines already described in the literature. The cell line carries the antigen defined by the Ki-1 monoclonal antibody, shows myeloid markers on a proportion of cells and has cytoplasmic UCH-T1.

Immuno-enzymatic detection of fibronectin in normal and pathological haematopoietic tissue

Cryostat sections of bone marrow biopsies were stained immuno-enzymatically for fibronectin using the alkaline phosphatase: anti-alkaline phosphatase (APAAP) technique. In normal marrow fibronectin was present only in megakaryocytes and the walls of blood vessels. In contrast, myelofibrotic bone marrow possessed an extensive distribution of fibronectin which did not correspond to the distribution of reticulin. Infiltrated and hypercellular marrows showed an increase in fibronectin which appeared to be related to increased marrow vascularity. Again no correlation with the reticulin pattern was evident. In contrast to platelets, other circulating blood cells had no demonstrable fibronectin. This study suggests that fibronectin does not act as a mediator of haemopoiesis in vivo as has been suggested by the results of experiments in non-human models.

Giant cell myocarditis: evidence for the macrophage origin of the giant cells

In order to elucidate the origin of giant cells in giant cell myocarditis a case has been studied immunohistologically using monoclonal antibodies against a variety of antigens, including those associated with muscle and macrophages. The results strongly suggest that the giant cells are derived from macrophages rather than the muscle cells.

Tissue distribution and ultrastructure of B lymphocytes reacting with the monoclonal antibody anti-Y29/55

The reactivity of normal tonsilar cells with the monoclonal antibody anti-Y29/55 is characterized at the tissue and ultrastructural cytological level. Using an indirect immuno-alkaline phosphatase method on frozen sections the antibody labels mantle zone and germinal center lymphocytes. This staining reaction is more generalized in B-lymphocyte areas than that obtained with antibodies to IgM and IgD. By indirect immunoperoxidase staining, as well as by an indirect rosetting procedure in cell suspensions, the reactive cell population were either small resting lymphocytes or activated lymphocytes corresponding to centrocytes, centroblasts, immunoblasts and plasmoblasts; some plasma cells were also labeled. These results characterize the monoclonal antibody anti-Y29/55 as a pan-B-marker antibody, useful for labeling resting and activated peripheral B-lymphocytes in frozen tissue sections and cell suspensions.

Binding of different antigen-enzyme and antibody-enzyme conjugates by intracellular antibodies in cytoplasm and Golgi complex of plasma cells. A double immunocytochemical study

Intracellular immunoglobulins in plasma cells were characterized by antigen-enzyme conjugates and anti-immunoglobulin antibody-enzyme conjugates applied in a double immunocytochemical approach. After their assemblage, immunoglobulins in the cytoplasm of anti-TNP anti-body producing plasma cells can be demonstrated both by TNP-enzyme conjugates and by anti-immunoglobulin (mu or gamma chain specific) antibody-enzyme conjugates. Once arrived in the Golgi complex (GC) detection with TNP-enzyme conjugates remains possible, but anti-immunoglobulin anti-body-enzyme conjugates did not bind to a detectable degree. Similar results were obtained in experiments where immunoglobulin-enzyme conjugates were used both as an antigen-enzyme conjugate and as an antibody-enzyme conjugate.

Bone marrow macrophages and megakaryocytes express common acute lymphoblastic leukaemia antigen

Common acute lymphoblastic leukaemia antigen (CALLA) was demonstrated on a proportion of bone marrow macrophages and megakaryocytes. CALLA was detected by two monoclonal antibodies (J5 & BA3) in a three-layer immunoalkaline phosphatase system applied to routine air-dried bone marrow smears. The J5 staining was confirmed by an indirect immunofluorescent method and the CALLA was shown to be at the surface of the macrophages and megakaryocytes by an indirect immunogold technique. The findings are discussed in relation to the known tissue distribution of CALLA and to the clinical use of anti-CALLA antibodies for bone marrow purging.

Epidermal synthesis and expression of HLA-DR on keratinocytes in lupus erythematosus

It has been suggested that aberrant expression of HLA-DR plays an important role in the induction of an autoimmune reaction. In lupus erythematosus (LE), skin represents a major target for autoimmune attack. We therefore tested lesional and nonlesional skin from 11 patients with different clinical subtypes of LE for the presence of HLA-DR molecules on keratinocytes using a monoclonal antibody against a non-polymorphic HLA-DR determinant. In all lesions tested, HLA-DR-positive keratinocytes were present, whereas in nonlesional skin, these cells remained HLA-DR negative. To exclude the possibility of passive absorption of DR molecules, the de novo synthesis of HLA-DR was demonstrated by the presence of cytoplasmic HLA-DR gamma chains in keratinocytes. If aberrant HLA-DR expression is a primary event, it could facilitate the recognition of autoantigens on keratinocytes by immunocompetent cells. Alternatively, the synthesis of DR molecules could be induced as a secondary event by mediators derived from the inflammatory infiltrate.

Early local reaction and lymph node permeation of rat carcinoma HH9-cl 14 cells. An immunohistological approach

2 X 10(6) ascites tumor cells of a DMBA-induced rat mammary adenocarcinoma (HH9-cl 14) were injected subcutaneously into tumor-free syngeneic female rats. Investigations were made, in addition to conventional paraffin histology and light microscopy, with immunohistological methods using poly-and monoclonal antisera. From 10 minutes to 2 hrs after inoculation carcinoma cells were seen inert either as single cells or as little clusters between connective and fatty tissue. After 6 hrs the number of tumor cells had decreased, and an increasing quantity of macrophages were found in close contact with them. At this stage some lymphocytes, too, appeared in the inoculation area. 10 minutes after injection, tumor cells were already entering regional lymph nodes and could be observed in the subcapsular sinuses. 2 hours later they had almost traversed the intermediate and medullary sinuses. Up to 6 hours after injection, increasing numbers of macrophages and sinus endothelial cells were seen, and the lymph node's appearance manifested hyperplasia of the paracortical zone. 4 and 6 hrs after injection, the total number of tumor cells in regional nodes decreased again noticeably, and sometimes tumor cells had disappeared. The first lymph node metastases appeared 28 days after inoculation.

Normal and neoplastic Langerhans cells: phenotypic comparison with other types of macrophages

The antigenic properties of normal epidermal Langerhans cells and their neoplastic counterparts (histiocytosis X cells) were compared with those of other types of macrophages, by immunohistochemical staining of skin and lymph node biopsies with a panel of mono-clonal antibodies. The phenotype of Langerhans cells, histiocytosis X cells, dermal macrophages and interdigitating reticulum cells were similar (HLA-DR+, OKT 6+/-, Leu3+/-, C3-receptor-, Ig-complex-, R4/23-, MO2-), and differed markedly from those of follicular dendritic cells (HLA-DR-, OKT6-, Leu3-, C3 receptor+, Ig+, R4/23+, MO2-, and histiocytic reticulum cells (HLA-DR+/-, OKT6-, Leu3+/-, C3-receptor+, Ig-complex+, R4/23-, MO2+/-). This indicates that Langerhans cells are related to the interdigitating reticulum cells found in the T cell areas of lymphoid organs, and demonstrates that Langerhans cells do not express C3b, C3bi or C3d receptor molecules. Our data also emphasise that the Leu3 antigen is not restricted to cells of the T cell lineage.

Immunoglobulin negative follicle centre cell lymphoma

Immunoglobulin (Ig) could not be detected on the surface or in the cytoplasm of neoplastic cells from five cases of follicle centre cell lymphoma with centroblastic/centrocytic follicular histology when examined by immunohistology of frozen or wax embedded sections. Examination by fluorescein labelled antibodies of cells in suspensions prepared from the biopsies revealed a monotypic surface Ig positive population in one case and a surface or cytoplasmic Ig kappa:lambda light chain imbalance in a further two cases consistent with neoplastic B cell involvement: in all cases the proportion of cells failing to express Ig or T cell markers ranged from 24 to 75%. The monoclonal antibodies B1 (Pan B cell), FMC4 (HLA class II) and J5 (cALL antigen) stained the majority of cells in suspension with residual cells staining with UCHT1 or OKT11 (T cell monoclonal antibodies). In frozen sections, neoplastic follicular cells did not stain with UCHT1. However, in the one case tested these cells stained with the antibodies B1 and FMC4. In paraffin sections J chain could be demonstrated in the cytoplasm of three out of five cases. Cells from four cases were cultured in vitro for Ig production: two failed to produce Ig and monotypic light chains were the sole Ig product of the remaining two cases. The failure to express Ig by the majority of the neoplastic cells from the cases described in this report is at variance with the follicular histology of these neoplasms. Mechanisms responsible for this failure are discussed with reference to current models of B cell differentiation.

Human lymphoid cells express epithelial membrane antigen. Implications for diagnosis of human neoplasms

Epithelial membrane antigen (EMA) is generally assumed to be expressed only on epithelial cells. However, EMA was also found on reactive and neoplastic plasma cells, on some non-Hodgkin's lymphomas (particularly cases of T-cell lymphoma and "malignant histiocytosis"), and on Reed-Sternberg cells in cases of lymphocyte-predominant Hodgkin's disease. EMA was also induced on normal blood lymphocytes by exposure to human T-lymphotropic virus type II or phytohaemagglutinin. The specificity of these aberrant reactions was confirmed by the use of three different monoclonal anti-EMA antibodies (E29, HMFG2, and LICR.LON/M8), and by showing that EMA in lymphoid tissue is similar in molecular weight to EMA in human milk. These results indicate that additional anti-epithelial antibodies (eg, anti-cytokeratins) should be used in conjunction with anti-EMA for tumour diagnosis.

Transferrin receptor on endothelium of brain capillaries

The blood/brain barrier prevents the passive diffusion of proteins and metabolites from cerebral blood vessels into tissue spaces around neuronal and glial cells. To provide nutrients for these cells, transport mechanisms must exist and indeed have been demonstrated for metabolites. We now show that monoclonal antibodies against rat and human transferrin receptors label blood capillaries in the brain but not in other tissues. In the rat this labelling occurs after injection of antibody into the blood, thus the receptors seem to be accessible at the endothelial surface. It is possible that transferrin receptors are expressed on these cells to allow transport of transferrin (and thus iron) into brain tissues.

The immunocytochemical detection of axillary micrometastases in breast cancer

The histological detection of tumour metastases in axillary lymph nodes from cases of breast carcinoma is of major prognostic significance, but may be difficult when metastases are of microscopic size. We have therefore investigated whether immunohistological techniques can increase the accuracy of metastasis detection in axillary lymph nodes. Forty-five cases of breast carcinoma were studied, in all of whom the axillary lymph nodes had been reported as free of metastases. Paraffin sections from these cases were stained by immunoenzymatic techniques, using monoclonal antibodies directed against human milk fat globule membrane antigen ("anti-EMA") and against epithelial intermediate filaments ("anti-keratin"). In 4/12 cases of lobular carcinoma and in 3/33 cases of ductal carcinoma, previously unsuspected micrometastases were revealed by immunohistological staining, representing an overall increase in detection rate of 15% (and of 33% for the lobular carcinoma cases). In addition to this group of 45 histologically "negative" biopsies, 12 samples were studied in which only a proportion of the nodes had been reported as containing tumour. In 5 of these cases immunostaining revealed previously undetected metastases. These findings suggest that immunohistological analysis may have a routine role to play in the staging of breast carcinoma. It is noted that the 15% increase in diagnostic accuracy achieved in the present study is comparable to the proportion of breast carcinoma patients in whom disseminated disease develops despite their axillary lymph nodes being reported as tumour-free at the time of surgery.

Freeze-dried paraffin-embedded human tissue for antigen labelling with monoclonal antibodies

Conventional fixation and paraffin embedding of human tissue destroys most of the antigens detected with currently available antibodies, while cryostat sections give poor morphological detail and require freezer space for storage. However, when tissue was freeze-dried before being embedded in paraffin S then stained for a wide range of antigens recognised by monoclonal antibodies (including T-cell and B-cell antigens), morphological preservation was clearly better, and the labelling reactions were of equal (or greater) intensity, than with cryostat sections. As the number of diagnostically important monoclonal antibodies continues to increase the use of freeze-dried paraffin sections should facilitate the introduction of immunohistological techniques for both routine histopathological diagnostic work and immunological research.

Immunocytochemical detection of T and B cell populations in routine blood smears

Immunofluorescence labelling of peripheral blood mononuclear cells is usually done on cells in suspension. This paper describes a procedure based on immuno-alkaline phosphatase staining of routine blood smears. The advantages of this method are that a few drops of blood are sufficient for labelling multiple lymphocyte subpopulations; smears may be stored for long periods before labelling; it is unnecessary to isolate a mononuclear cell fraction before labelling; labelled preparations can be stored; and the morphological features of labelled cells are shown clearly. The technique was used to label T cells and their subsets, B cells, and HLA-DR antigen in blood smears from 15 normal donors, from 7 patients with infectious mononucleosis, from 1 patient with clinically proven AIDS, and from 1 symptom-free subject at risk of AIDS. The normal T helper/suppressor ratio of 1 X 95 was reversed in all of the last three groups of subjects, the mean being 0 X 34 for infectious mononucleosis; the value was 0 X 22 in the AIDS patients. Immuno-alkaline phosphatase labelling of routine blood smears seems to be a valuable method for studying abnormalities in circulating lymphocyte subpopulations and lends itself to mass screening for altered T helper and T suppressor subjects-for example, in blood donors.

In situ immunological characterization of Langerhans cells with monoclonal antibodies: comparison with other dendritic cells in skin and lymph nodes

The antigenic properties of epidermal Langerhans cells (LC) were determined and compared with those of non-lymphoid dendritic dermal cells (DDC), interdigitating reticulum cells (IRC), dendritic reticulum cells (DRC), and histiocytic reticulum cells (HRC) by examination of serial and double immunoenzymatic and -fluorescence stained frozen sections of skin and lymph node biopsies. All of these cell types expressed leucocyte common antigen. LC, DDC, and IRC demonstrated similar antigenic phenotypes (HLA-DR+, Leu3+, OKT6+/-, anti-C3 receptor-, R4/23-, Ig-complex-, MO2-), whereas the antigenic properties on DRC (HLA-DR-, Leu3-, OKT6-, anti-C3 receptor+, R4/23+, Ig-complex+, MO2-) and HRC (HLA-DR+/-, Leu3-, OKT6-, anti-C3 receptor+ R4/23-, Ig-complex+, MO2+) were markedly different. These data suggest that LC, DDC, and IRC are closely interrelated cell types, and support the concept that DRC and HRC are unique cell types which do not appear to be related to LC, DDC, or IRC. The lack of labelling of LC with monoclonal anti-C3b receptor antibody, and polyclonal antiserum recognizing C3b, C3bi, and C3d receptors strongly indicate that the EAC-rosetting of LC previously described is not due to the presence of C3 receptors on these cells. Alternatively, LC may express C3 receptor molecules different from those previously identified (C3b, C3bi, and C3d).

Immunoenzymatic staining of haematological samples with monoclonal antibodies

This paper describes the use of immunoenzymatic techniques (and in particular a recently developed immuno-alkaline phosphatase procedure) for labelling haematological samples with monoclonal antibodies. Since cells are smeared and fixed before staining it is possible to combine optimal preservation of cellular detail with visualization of positive labelling. Additional advantages over conventional immunofluorescent procedures for detecting cellular antigens include the fact that samples may be stored for long periods both before and after staining, and that double labelling may readily be performed (either by combining immunoenzymatic staining with T cell rosetting or by performing immunoperoxidase and immuno-alkaline phosphatase techniques sequentially). Furthermore, these methods may be applied to samples containing too few cells for conventional examination (e.g. samples of cerebrospinal fluid). A total of 16 different antigens (including HLA-DR, common ALL antigen and antigens associated with T cells, B cells, erythroid cells and megakaryocytes) were demonstrated by immuno-enzymatic staining on a range of normal and neoplastic haematological samples. It is concluded that this approach to cellular antigen labelling is of potential value not only in routine haematological diagnosis, but also for research in many immunological and haematological fields.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P < 0.05, P < 0.0001, and P < 0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P < 0.005 and P < 0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P < 0.0001 and P < 0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.