Identification of histiocytic reticulum cells by the immunohistochemical demonstration of factor XIII (F-XIIIa) in human lymph nodes

Morphologically and enzyme histochemically distinguishable tissue macrophages and stromal cells of human reactive lymph nodes were characterized by the cytoplasmic presence of the subunit A of factor XIII and by the expression of surface antigenic determinants reacting with monoclonal antibodies directed against monocyte/macrophage populations (Mo 1, Leu M3) and HLA-DR antigens. The distribution of F-XIIIa positive cells was studied on formaldehyde-fixed paraffin-embedded sections with immunoperoxidase techniques. established on cryostat section with double immunofluorescence. Alpha-Naphthyl acetate esterase (ANAE) reaction was The immunophenotype was established on cryostat sections with double immunofluorescence. Alpha-Naphthyl acetate esterase (ANAE) reaction was carried out on these cryostat sections to identify tissue macrophages. The antibody against F-XIIIa detected histiocytes in both intra- and extra-sinusoidal locations which were ANAE+, Mo 1+, Leu M3+ and HLA-DR-. F-XIIIa was also present in fibroblast-like mesenchymal cells with the following phenotypic characteristics: ANAE-, Mo 1+, Leu M3+ and HLA-DR+. The anti F-XIIIa antibody did not stain lymphoid cells, granulocytes, epithelial cells, endothelial cells and mast cells. The immunohistochemical detection of F-XIIIa works on formaldehyde-fixed paraffin-embedded sections. The most promising application seems to be the identification of histiocytes in lymphoid and histiocytic proliferations.     

Lymphomatoid papulosis. Characterization of skin infiltrates by monoclonal antibodies

Cryostat sections from fully developed papular lesions of lymphomatoid papulosis (histologic subtype A or B) have been examined by immunoenzymatic staining with 24 monoclonal antibodies against lymphoid cells and their subsets. The lesions demonstrated essentially identical cellular compositions and consisted of T-lymphocytes with a peripheral phenotype (Lyt3+, anti-Leu-4+, OKT6-), macrophages (HLA-DR+, EB11+, OKM1+), and Langerhans cells (HLA-DR+, OKT6+). T-helper/inducer cells (anti-Leu-3+) usually dominated over T-suppressor/cytotoxic cells (anti-Leu-2+). In all cases, proportions of the infiltrating T-cells expressed markers associated with activation (HLA-DR, the OKT1O antigen, interleukin-2 receptor) or proliferation (transferrin receptor, the Ki-67 antigen) of lymphoid cells. Furthermore, the infiltrates contained clusters and/or sheets of large cells reactive with antibodies (Ki-1, Ki-24, Ki-27), which recognize Hodgkin's and Reed-Sternberg cells. These data indicate an origin of the cellular infiltrate from transformed or activated lymphoid cells and suggest an interrelationship of lymphomatoid papulosis to Hodgkin's disease.     

Hepatic vascular endothelial cells heterogenously express surface antigens associated with monocytes,macrophages and T lymphocytes

Summary During studies of the antigenic and functional properties of hepatic sinusoidal lining cells in situ, we found that only the sinusoidal endothelial cells share antigens with a peripheral blood macrophage subset capable of presenting soluble antigens and triggering autologous mixed lymphocyte reactions. They were HLA-DR+, OKM1–, OKM5+. Vascular endothelial cells in the portal areas and central veins were HLA-DR+, OKM1– and OKM5–. The sinusoidal endothelial cells also expressed an antigen found on helper/inducer (OKT4 and Leu3 a) T lymphocytes. Thus, the present study suggests that endothelial cells in different anatomic compartments in the liver heterogenously express surface antigens associated with monocytes, macrophages and T lymphocytes and possess distinct immunological functions.     

Analysis of large-cell lymphomas using monoclonal and heterologous antibodies.

Fifteen cases of large-cell lymphoma, diagnosed as centroblastic (5), B-immunoblastic (5) or true histiocytic (5). lymphoma and one case of malignant histiocytosis were studied with monoclonal antibodies. Each diagnosis was based on morphological as well as marker studies. A panel of monoclonal and heterologous antibodies against T lymphocyte differentiation antigens (Leul, Leu2a, Leu3a, OKT4, OKT8, TA1), B lymphocyte subsets (BA1, BA2, HLA-DR, alpha C3b receptor antiserum, surface immunoglobulins), the common acute lymphoblastic leukaemia antigen (CALLA), monocytes/macrophages (OKM1, anti-human monocyte 1, TA1, Mac1, HLA-DR, anti-C3b receptor), myeloid cells (VIM-D5, elastase, OKM1) and the cells of the Langerhans cell/interdigitating reticulum cell series (OKT6, NA1/34). The results show a specific staining pattern for true histiocytic lymphoma (histiocytic sarcoma). Centroblastic and B-immunoblastic lymphomas showed gradual differences with mostly strong staining for HLA-DR and weak with anti C3b receptor for B-immunoblastic lymphomas in contrast to centroblastic lymphomas. Staining with BA1 and BA2 indicated immunological heterogeneity in these lymphomas. The number of admixed cells was usually low with few B cells and a shift in the ratio helper/inducer to suppressor/cytotoxic T cells in favour of the suppressor/cytotoxic subset.     

Macrophage differentiation in atherosclerosis. An in situ immunohistochemical analysis in humans.

The differentiation of macrophages present in diffuse intimal thickening, fatty streaks, and atheromatous plaques, was analyzed with immunohistochemical methods, using segments of aorta, coronary, and carotid arteries obtained at autopsy. Various differentiation antigens were studied with the monoclonal antibodies anti-HLA-DR, EBM-11, Leu M3, OKM1, and OKM5. Adjacent sections were stained for lipids (oil red O) and lysosomal activity (acid phosphatase). Almost all macrophages identified with the pan-macrophage antibody EBM-11, also stained with the anti-HLA-DR antibody. Diffuse intimal thickening showed a predominance of Leu M3+ cells; fatty streaks also showed OKM1+ and OKM5+ macrophages. Classical atheromatous plaques showed a gradual shift in phenotypic expression towards the center of the lesion. Cells in the superficial layers were positive only with Leu M3, deeper localized cells showed double expression of Leu M3 and OKM1 or double expression of OKM1 and OKM5. Cells that were localized adjacent to the atheromatous debris stained only with OKM5. The phenotypic changes occurred in parallel with an increase in both fat uptake and lysosomal activity of the macrophages. This shift in phenotypic expression suggests a process of differentiation and maturation of the macrophages involved. The results indicate that macrophages within the arterial intima are activated and mature towards cells that express receptors for adhesion proteins and complement during the development of atherosclerotic plaques. This may imply that the macrophages involved in lipid metabolism also have a potential to act as effector cells in a chronic inflammatory process, and thus, may contribute to the progression of an atherosclerotic plaque. Functional studies of macrophage subpopulations are needed to verify this hypothesis.     

Cytochemical profile of megakaryoblastic leukaemia: a study with cytochemical methods, monoclonal antibodies, and ultrastructural cytochemistry.

A cytochemical study using: Sudan black B; alpha-naphthyl acetate (ANAE) staining; estimation of alpha-naphthyl butyrate (ANBE) esterase activity; acid phosphatase activity; and 5' nucleotidase activity was carried out in 15 cases of megakaryoblastic leukaemia. These included cases of M7 acute myeloid leukaemia and blast crises of chronic granulocytic leukaemia. The megakaryoblastic nature of the blasts was first established using two monoclonal antibodies against platelet glycoproteins, and by estimating the platelet/peroxidase reaction at ultrastructural level. Our findings suggest that megakaryoblasts have a typical cytochemical profile comprising positive ANAE staining and acid phosphatase activity with a predominant localisation in the Golgi zone and negative or weak ANBE activity. A similar positive cytochemical pattern was also found in five cases of erythroleukaemia (M6). The specificity of the 5'nucleotidase activity for megakaryoblasts was not confirmed. In most cases of megakaryoblastic leukaemia there was no 5'nucleotidase activity only two cases showed positive reactions--reactions were positive in several cases of myeloblastic and lymphoblastic leukaemia. We suggest that cytochemical methods may be useful in diagnosing M6 and M7 acute leukaemia because less than 40% of leukaemic cells react with specific monoclonal antibodies.     

In situ immune complexes, lymphocyte subpopulations, and HLA-DR-positive epithelial cells in Hashimoto thyroiditis

Surgical specimens from thyroid glands from seven patients with Hashimoto thyroiditis and two patients with non-autoimmune colloid goiter were analyzed by immunohistologic techniques (direct and indirect immunofluorescence and immunoperoxidase tests) using polyclonal antisera against total immunoglobulin, Ig classes (IgM, IgD, IgG, and IgA), and complement component C3 and monoclonal antibodies specific for B cells, T cell subpopulation, macrophages, natural killer cells, granulocytes, and HLA-DR antigen. Complement-fixing immune complexes (IgG+, C3+) were noted predominantly in areas with only slight destruction and only moderate lymphoid infiltration of thyroid follicles. In areas with intense lymphoid infiltration of thyroid follicles, where many well-developed germinal centers and significant perivascular lymphoid infiltration were seen, immune complexes were scarce. In these latter areas T helper cells (OKT4+, Leu3a+), were more abundant than T cytotoxic/suppressor cells (OKT8+), macrophages (OKM1+), and plasma cells (IgG+); only a few B lymphocytes (smIgM+, smIgD+), granulocytes (ViMD5+), and natural killer cells (VEP13+, Leu7+) were noted in the interstitium between thyroid follicles, intruding between thyroid follicular epithelial cells and merging into the thyroid follicular lumen. Many activated T cells (OKT10+, HLA-DR+) were present in these areas of advanced destruction. HLA-DR antigen expression was seen on macrophages, tissue reticulum cells, vascular endothelial cells, lymphoid cells, and, most interestingly, on thyroid epithelial cells. Normal thyroid epithelial cells did not express HLA-DR. Only a few epithelial cells in the vicinity of lymphoid infiltrations were HLA-DR+ in early stages of Hashimoto thyroiditis, and the number of HLA-DR+ epithelial cells was significantly increased in advanced stages of the disease. In our present report the potential role of HLA-DR+ thyroid epithelial cells for the in situ stimulation of the immune system within the thyroid gland of patients with Hashimoto thyroiditis is discussed, and it is hypothesized that HLA-DR+ thyroid epithelial cells may be an important factor for the progression and self-perpetuation of the disease, which is probably initiated by humoral components of the immune system but further propagated by cellular immunopathologic mechanisms.     

Human macrophages and T-lymphocyte subsets infiltrating nodules of Onchocerca volvulus.

The nature of the lymphoid infiltrate in nodules of Onchocerca volvulus was assessed using monoclonal antibodies to lymphoid cell surface markers. Although B cells were generally absent, T cells were present, but in variable amounts. The ratio of T4+ (helper phenotype) to T8+ (suppressor-cytotoxic phenotype) was usually in the normal peripheral blood range of about 3, although ratios ranging from 1 to 10 were seen in selected areas of the onchocercoma. The possibility of immunosuppression through dominance of T4+, Leu-8+ cells (suppressor-inducer phenotype) within the T4+ population was also excluded. The T cells did not tend to concentrate in close proximity to the parasite, and there was no general bias in favour of the T suppressor cell phenotype (T8) within the infiltrate. Macrophages and dendritic cells were consistently observed and consisted of three defined cell types in approximately equal proportions: normal, unactivated macrophages (HLA-DR-, acid phosphatase positive), activated macrophages (HLA-DR+, acid phosphatase positive) and cells of dendritic morphology (HLA-DR+, acid phosphatase negative). These results are discussed in relation to immune suppression in filariasis.     

Morphological heterogeneity of Leu7, Leu11 and OKM1 positive lymphocyte subsets: an ultrastructural study with the immunogold method.

The morphological features of normal peripheral blood lymphocytes reactive with three monoclonal antibodies (MoAb) against natural killer (NK) cells, Leu7, OKM1 (CD11b) and Leu11 (CD16) and with two anti-T cell MoAb, CD4 and CD8, have been analysed at ultrastructural level by an indirect immunogold method. Cells having the features of large granular lymphocytes (LGL) but also lymphocytes displaying different morphological characteristics (non LGL; e.g. high nucleo-cytoplasmic ratio and few cytoplasmic organelles) were seen reactive with each of the MoAb investigated. Leu7 identified a higher proportion of LGL (60-80%) than OKM1 (10-95%) and Leu11 (20-48%), and with a stronger binding. A distinct granular structure, recognized as parallel tubular arrays, was more characteristic of the Leu7+, CD8+ LGL and was less frequently seen in the OKM1 and Leu11 positive LGL subpopulation in four out of the five donors investigated. It is of interest that the Leu11 and OKM1 positive subsets, which correspond functionally to cells with greater NK function, had relatively less LGL than the Leu7 positive subsets, raising the issue of the true morphology of NK cells in man. The existence of a minority of CD4 positive LGL was confirmed. Our findings demonstrate that there is a degree of morphological heterogeneity within the normal NK lymphoid population as defined by the membrane phenotype and that certain variability among normal individuals regarding the proportion and structural features of the NK subpopulations may be present.     

Antigenic phenotype of the myeloid leukaemic cells defined by monoclonal antibodies

The antigenic characteristics of the leukaemic cell population in 31 patients with acute myeloid leukaemia (AML) and 5 patients with acute undifferentiated leukaemia (AUL) was investigated using a panel of 15 monoclonal antibodies (Mc Abs). We chose 14 Mc Abs that react with lineage--and stage related myeloid antigens and L243 Mc Ab that reacts with HLA-DR antigen. In AML cases we correlated the antigenic phenotype with morphological FAB classification. The study indicates a substantial antigenic heterogeneity of the surface antigen expression on leukaemia cells particularly in M1, M2 and M4 AML cases. The morphological subtype of these leukaemias tended to correlate with the immunologic phenotype, particularly in more differentiated AML cases such as M3 or M5. The most immature cell phenotype characterised "undifferentiated" AML, which was expressed by the reactivity or L243, BI3C5, MY9, VIM-2 and S3-13 Mc Abs with the majority of the patients. The analysis shows that although there is a tendency for the morphology to correlate with the surface antigen phenotype each morphological group contains patients having different surface antigen phenotype.     

Phenotypic expression of Hodgkin''s and Reed-Sternberg cells in Hodgkin''s disease.

The phenotypic expression of Hodgkin's and Reed-Sternberg (H-RS) cells was determined by analysis with a panel of monoclonal antibodies and peanut agglutinin (PNA) by an immunohistochemical technique. Seven antibodies, including T200, anti-HLA-DR, anti-Leu 10, A1G3, anti-Tac, OKT9, and anti-Leu M1, were found to react with a great majority of H-RS cells. In some cases, H-RS cells also bound PNA. Other antibodies, including those highly specific for T cells (eg, Lyt 3) and B cells (eg, B1, anti-Leu 14) were consistently negative. The results argue against the derivation of H-RS cells from T or B lymphocytes. The H-RS cells were also negatively stained with antibodies which react with monocytes (OKM1, Mo-2, 63D-3), follicular dendritic cells (DRC-1), and natural killer/killer cells (Leu 7, Leu 11a, B73.1). The presence of Leu M1 and Tac in H-RS cells is of interest. Anti-Leu M1 positivity was seen in all 20 of Hodgkin's disease (HD) cases tested and should provide a very useful reagent for differential diagnosis of HD from other reactive and neoplastic conditions. Tac normally is present only on activated T cells. The presence of Tac in H-RS cells may reflect expression of T-cell growth factor receptor or a closely related protein during a stage of neoplastic transformation. Although the nature of the neoplastic cell of HD cannot be determined by these studies, they are consistent with an origin from interdigitating reticulum cells. Both H-RS cells and interdigitating reticulum cells have a similar antigenic phenotype (Leu M1+, T200+, HLA-DR+, Leu 10+, A1G3+, and OKT9+) and a similar pattern of lysosomal enzyme activity.     

Potential antigen-presenting cells in normal extraocular muscles demonstrated with double immunoenzyme staining

Antigen-presenting cells are of crucial importance for the initiation and regulation of regional immune responses. In a previous study, indirect morphological evidence that morphologically normal human orbital tissues contain HLA-DR-positive macrophages, which may represent antigen-presenting cells, has ben obtained. In the present study, these cells were characterized in detail using double immunoenzyme staining techniques with monoclonal antibodies directed against several well-characterized monocyte/macrophage markers and against HLA-DR gene products. The orbital muscular tissues appear to contain numerous HLA-DR, monocyte/macrophage marker double-stained cells, which are considered to be potential antigen-presenting cells. The cells are widely distributed in the connective tissue of all the orbital muscular tissues studied and consist of several subsets with different phenotypes. Furthermore, site-specific differences were shown between recti muscles and the levator/Müller's muscles with respect to the distribution of HLA-DR and one monocyte/macrophage marker (OKM5). Many of the orbital antigen-presenting cells appear to be of the dendritic type and are considered to be of major importance in regulating local orbital immunity.     

Letterer-Siwe disease: Immunohistochemical evidence for a proliferative disorder involving immature cells of Langerhans lineage

Summary The morphological, ultrastructural and immunophenotypic properties of Histiocytosis-X (H-X) cells were investigated in a lymph node involved by Letterer-Siwe (L-S) disease. H-X cells were T6+ (CD1a), S-100+, T4+ (CD4) and HLA-DR+; in addition they were consistently T11+ (CD2) and were stained by antibodies directed against receptors for transferrin (T9), C3bi (OKM-1/CD11b), IgG-Fc (Leu-11/CD16) and Interleukin-2 (IL-2R/CD25). On immunostained cytosmears, T6+ cells were highly polymorphic and a prominent fraction (45%) showed immature morphology, characterized by lymphoid appearance. Cells expressing macrophage markers (ANAE, AACT, Leu-M3/CD14, PAM-1) were 10-fold fewer than T6+ cells and did not show a lymphoid morphology. At TEM level, H-X cells were characterized by poor content of LC granules and by the presence of myelin-like laminated bodies and of lysosome-like dense bodies. The immunophenotypic properties of H-X cells were compared to those of epidermal Langerhans cells (LCs) and of LCs present in lymph nodes of three cases of dermatopathic lymphadenitis. Epidermal LCs were T6+/HLA-DR+, and sometimes faintly T4+. Lymph node LCs were T6+, S-100+, T4+, HLA-DR+, and showed the same variety of surface receptors detected in H-X cells; furthermore, in a case with massive infiltration of the paracortex by T6+ cells, lymph node LCs were faintly T11+ and some of the T6+ cells had lymphoid aspect. Our findings suggest that the H-X cell population of L-S disease is not homogeneous, but is composed of discrete cell subsets with distinctive antigenic and morphological traits closely resembling those of cells of LC lineage at different maturational stages.Supported by CNR contract N. 86.00303.44, Progetto Finalizzato Oncologia, and by Fondazione Cenci-Bolognetti Istituto Pasteur     

Response of human T lymphocytes to phytohemagglutinin (PHA) after sequential depletion of monocytes, HLA-DR+, Leu11a+, and Leu7+ cells

The experiments presented in this paper deal with the question of whether there is an absolute requirement for alpha-naphtylacetate esterase (ANAE)-positive monocytes, HLA-DR+, Leu11a+, and/or Leu7+ cells to stimulate human peripheral blood T lymphocytes by phytohemagglutinin (PHA). Purified (p) T lymphocytes containing less than 0.1% ANAE-positive monocytes were isolated from human peripheral blood mononuclear cells (MNC) by sequential removal of carbonyl-iron phagocytic cells and of low-density cells by density gradient centrifugation and isolation of E-rosette-forming cells (E-RFC). These pT-cells were further depleted of HLA-DR+, Leu11a+, and/or Leu7+ cells using monoclonal antibodies and cell sorting. The T lymphocytes were stimulated by PHA in an ultra-micro culture in glass capillaries at a volume of 1 microliter or 2 microliters, containing 1000 cells per culture. With this method, the accessory cell requirement could be studied under limiting cell number conditions. The results show that pT-cells can be stimulated by PHA in the absence of ANAE-positive monocytes. No ANAE-positive monocytes were found in the culture after stimulation, indicating the lack of differentiation into ANAE-positive monocytes from ANAE-negative precursors. A rabbit antiserum against leukocytic pyrogen (LP, also containing anti-IL 1 activity) only reduced but did not abrogate the stimulation of pT-lymphocytes by PHA. Addition of adherent cells resulted in an enhancement or in an inhibition of the response of pT-lymphocytes to PHA, depending on cell concentration and culture time: The lower the number of cultured T lymphocytes and the shorter the culture time, the higher was the enhancing activity by additional adherent cells, and vice versa. Further purification of the pT-cells using monoclonal antibodies and cell sorting led to the finding that depletion of either HLA-DR+, Leu11a+, or Leu7+ from pT-cells only reduced but did not abrogate the stimulation of the pT-cells by PHA. However, in absence of HLA-DR+ and Leu7+ cells, the pT-lymphocytes totally failed to respond to PHA. This abrogation of the response was not observed when pT-cells were depleted of HLA-DR+ and Leu11a+ cells. In addition, T11+/HLA-DR- T lymphocytes isolated from E-RFC by positive selection in a cell sorter also responded to PHA.(ABSTRACT TRUNCATED AT 400 WORDS)     

Immunohistochemical studies of the spleen in hairy-cell leukemia.

Immunohistochemical studies of 10 spleens from patients with hairy-cell leukemia (HCL) with a battery of monoclonal and heterologous antibodies were performed in order to obtain information on the phenotype of the neoplastic cells and the admixture of reactive cells. The hairy cells (HCs) were shown to react with several anti-B-cell antibodies (Y29/55, Leu10, HLA-DR), but only a minority of cases showed reactivity with antibody BA-1. The cells of all cases were nonreactive with anti-T and/or anti-macrophage antibodies. In contrast with cell-suspension studies, in immunohistochemical studies the HCs did not react with antibody OKM1. The reactive T-lymphocytes showed a shift toward T helper cells in the red pulp, but not in the white pulp. It was confirmed that "pseudosinuses" and "bloodlakes" are outlined by HCs and not by sinus-lining cells: the lining cells of the blood lakes were Y29/55+ and Leu10+, but negative with antibodies known to react with sinus-lining cells (Leu2a, BA-2). These data suggest that immunohistologic studies of the spleen in patients with HCL can be helpful in differential diagnosis and can provide information concerning the reaction of splenic tissue to the infiltration by hairy cells.     

Properties of human natural interferon-producing cells stimulated by tumor cell lines

Human peripheral blood mononuclear leukocytes cocultured with WISH human amnion cells or K562 tumor cells rapidly produce interferon-alpha (IFN). In the present report we characterize the IFN-producing cells (IPC) in this system by cell separation procedures, including panning with different monoclonal antibodies. Two types of cells which were responsible for the IFN production could be identified. The first IPC was classified as monocyte/macrophage because it was present in plastic-adherent cells and apparently carried the OKM1 antigenic marker. T and B lymphocytes were not involved in the IFN production. The second type of IPC was nylon wool-nonadherent, sheep erythrocyte rosette-negative, at least partly Fc receptor-negative and resided in light Percoll density gradient fractions. The natural killer activity and IFN-producing capacity was studied in such cells fractionated by the panning technique, utilizing HNK-1, OKT10 and OKM1 antibodies. When WISH and K562 were used as IFN inducers, HNK-1+ and OKT10+ cells with lytic activity against K562 produced little or no IFN. The IPC were instead confined to HNK-1- and OKT10- cells. With cells fractionated with respect to the OKM1 antigen, natural killer activity against K562 and WISH cells and IFN production stimulated by K562 cells resided in the OKM1+ cells. In marked contrast, cells producing IFN in response to WISH cells were OKM1-. The results therefore demonstrate a dissociation between natural killer cells against tumor cells and IPC stimulated by the same targets, suggesting that for at least certain targets/inducers they may represent distinct entities.     

Immunophenotypic differences between osteoclasts and macrophage polykaryons: immunohistological distinction and implications for osteoclast ontogeny and function.

The antigenic phenotype of human fetal osteoclasts was compared with that of human tissue macrophages and macrophage polykaryons in foreign body lesions using a large number of monoclonal antibodies directed against myeloid (granulocyte/mononuclear phagocyte) antigens. Osteoclasts expressed a restricted range of macrophage-associated antigens including CD13, CD15A, CD44, CD45, CD54, (ICAM-1), CD71 (transferrin receptor), and CD68. These antigens were also present on macrophages and macrophage polykaryons both of which also strongly expressed CD11a,b,c, CD18, (LFA family), CD14, CD31, CD36, CD37, CD39 and CD43 antigens. There was also weak and occasional expression of CD16 (FcRIII), CD25 (interleukin 2 receptor), CD32 (FcRII), CD35 (C3b receptor) and HLA-DR by macrophage polykaryons. The presence of some macrophage associated antigens on osteoclasts is consistent with their originating from cells of the mononuclear phagocyte system. The numerous differences in antigenic phenotype between osteoclasts and macrophage polykaryons, however, suggest that their pathways of development and differentiation are not identical. The differences discerned in antigenic phenotype should also permit distinction between these polykaryons (and possibly their mononuclear precursors) in normal and diseased tissues.     

Reactivity pattern of anti-CD1 and anti-HLA class II monoclonal antibodies with human eccrine sweat glands

The known cross-reactivity of monoclonal antibodies prepared against CD1 and HLA-DR antigens with skin components prompted us to study the reactivity pattern of human eccrine sweat glands with a panel of monoclonal antibodies directed against CD1 antigens (OKT6, BL6, D-47) and against HLA-class II antigens (anti-DR, BL2, LEU-10, IV-D12, MAJA-7). The labelling pattern of eccrine glands with the panel of monoclonal antibodies used in this study permits to establish three different antigenic compartments on eccrine glands: 1) acrosyringium and distal part of dermal duct anti-DR+, BL2+, LEU-10+, IV-D12+; 2) proximal part of dermal duct MAJA-7+; 3) secretory part D-47+. The immunological markers used in this work provide a useful tool for investigation of eccrine gland differentiation and human eccrine glandular pathology.     

Immunocytology of plasmacytoid T cells: marker analysis indicates a unique phenotype of this enigmatic cell

Clusters of plasmacytoid T cells (PTC) were detected in axillary lymph nodes draining an invasive ductal breast cancer in a 64-year-old woman. Immunocytology of PTC revealed a remarkable antigenic profile. Analysis with a broad spectrum of monoclonal antibodies demonstrated that PTC bear the CD4 surface antigen (Leu-3a+ and OKT4+), the transferrin receptor (OKT9+), and components of the HLA class-II antigens (TU35+, TU39+, Leu-10+). Surprisingly, PTC were stained by two monoclonal antibodies recognizing monocytes and macrophages (Ki-M6 and Ki-M7). Finally, Leu-8, which detects most mature T lymphocytes, also identified the PTC, and all pan T-cell markers (Leu-1, UCHT 1, and Lyt 3) were constantly negative. The cytogenesis and the functional properties of PTC remain a matter of discussion.     

The immunologic and ultrastructural characterization of the cellular infiltrate in acute cardiac allograft rejection: prevalence of cells with the natural killer (NK) phenotype

The inflammatory cell infiltrates in 15 endomyocardial biopsies serially obtained from a human cardiac allograft during a 1 1/2-year period were characterized. An indirect immunofluorescent technique with hybridoma-derived monoclonal antibodies which preferentially react with B lymphocytes (anti-Ia), mature T cells (OKT3, Leu 1), and helper (OKT4b,d) and supressor/cytotoxic (OKT8) T-cell subsets and with natural killer cells, macrophages, and granulocytes (OKM1) was used. During each of seven rejection episodes the overwhelming majority of infiltrating cells in the endomyocardial biopsy were OKM1+Ia. These cells displayed short microvilli, a moderate amount of cytoplasm, numerous mitochondria, a large amount of rough endoplasmic reticulum, Golgi, and an indented nucleus, that is, the ultrastructural features of large, granular lymphocytes. Thus, they morphologically and phenotypically resemble those lymphoid cells which have been shown to possess natural killer (NK) functions in man. Occasional Leu 1+OKT3+ cells, some of which were OKT8+, were also seen during acute rejection. In each instance following therapy and resolution of the rejection episode only rare OKM1+Ia- cells were present. At this time the majority of the cells were Leu 1+OKT3+OKT8+. Routine biopsies, performed at times without evidence of rejection, showed only reactivity for Ia antigens by the capillary endothelium. These studies demonstrate the prevalence of cells with the natural killer phenotype in this human cardiac allograft during episodes of acute graft rejection.