A novel endothelial-specific membrane protein is a marker of cell-cell contacts.

mAbs were raised in mice against cultured human endothelial cells (EC) and screened by indirect immunofluorescence for their ability to stain intercellular contacts. One mAb denoted 7B4 was identified which, out of many cultured cell types, specifically decorated cultured human EC. The antigen recognized by mAb 7B4 is bound at the appositional surfaces of cultured EC only as they become confluent and is stably expressed at intercellular boundaries of confluent monolayers. EC recognition specificity was maintained when the antibody was assayed by immuno-histochemistry in tissue sections of many normal and malignant tissues and in blood vessels of different size and type. The antigen recognized by 7B4 was enriched at EC intercellular boundaries similarly in vitro and in situ. In vitro, addition of mAb 7B4 to confluent EC increased permeation of macromolecules across monolayers even without any obvious changes of cell morphology. In addition, when EC permeability was increased by agents such as thrombin, elastase, and TNF/gamma IFN, its distribution pattern at intercellular contact rims was severely altered. mAb 7B4 immunoprecipitated a major protein of 140 kD from metabolically and surface-labeled cultured EC extracts which appeared to be an integral membrane glycoprotein. On the basis of its distribution in cultured cells and in tissues in situ, 7B4 antigen is distinct from other described EC proteins enriched at intercellular contacts. NH2-terminal sequencing of the antigen, immunopurified from human placenta, and sequencing of peptides from tryptic peptide maps revealed identity to the cDNA deduced sequence of a recently identified new member of the cadherin family (Suzuki, S., K. Sano, and H. Tanihara. 1991. Cell Regul. 2:261-270.) These data indicate that 7B4 antigen is an endothelial-specific cadherin that plays a role in the organization of lateral endothelial junctions and in the control of permeability properties of vascular endothelium.

Natural killer activity in spleens and lymph nodes from patients with Hodgkin's disease.

Natural killer (NK) activity against K-562 myeloid cell line was evaluated in 21 spleens and 14 lymph nodes from patients with Hodgkin's disease (HD). NK activity of eight HD-involved (HD+) spleens [556 lytic units (LU)] was found 5-fold higher than that of 13 HD-uninvolved (HD-) spleens (112 LU) (p less than 0.01). Moreover, NK activity of HD+ spleens was significantly different (p less than 0.05) from that of three spleens involved by non-HD lymphoma (100 LU). NK activity of four spleens from nonneoplastic patients (250 LU) was intermediate between those of HD+ and HD- spleens. Lymph node cells were about 10-fold less cytotoxic. NK activity of seven HD+ lymph nodes (43 LU) was 3-fold higher than that of three lymph nodes involved by non-HD lymphoma (8 LU). However, these differences were not statistically significant. Our data are compatible with increased NK activity in HD+ tissues as well as with depressed NK activity in HD- tissues. The observation that NK activity of peripheral blood leukocytes from nine HD patients (116 LU) (p less than 0.05 only at 100:1 effector:target cell ratio) may support the latter interpretation. Partial characterization of effector cells in HD+ and in HD- spleens indicated that, in both instances NK cells were nonadherent and almost equally distributed between the erythrocyte-negative and -positive cell fractions. Finally, NK activity of both HD+ and HD- spleen cells could be further potentiated in vitro by interferon.

Intratumoral microvessel density and expression of ED-A/ED-B sequences of fibronectin in breast carcinoma.

The aim of this study was to examine the correlation between intratumoral microvessel density (iMVD) and the presence of cellular fibronectin isoforms, ED-A and ED-B, in order to identify those tumours with a prominent angiogenic phenotype. 91 cases of invasive ductal breast carcinoma were evaluated for TNM, histological grading, percentage of Ki-67+ cells and receptor hormonal status. iMVD was determined as a single microvessel count in a 200 x microscope field from the region of the tumour that appeared to be most densely vascular. When the mean values of iMVD of the various groups were compared, no significant difference was noted (Mann-Whitney test). When tumours were classified as high or low iMVD, based on a cut-off value (99 vessels/0.74 mm2), cases with high iMVD were significantly more numerous in poorly differentiated G3 tumours (P = 0.01, Chi-square test), and in tumours with lymph node metastasis (N0 versus N1 + N2; P = 0.002). The possibility that high iMVD was the expression of prominent vascular neoformation was explored using ED-A and ED-B isoforms of fibronectin as markers of neoformed vessels. ED-A + and/or ED-B + blood vessels were < 10% of total vessels, were detected in approximately 50% of cases independently of iMVD values, and were not more numerous in tumour areas with hot spot vascularisation. Our findings indicate that iMVD and expression of ED-A/ED-B reflect different aspects of tumour-associated angiogenesis.

The benign cystic lymphoepithelial lesion of the parotid gland is a viral reservoir in HIV type 1-infected patients.

The presence of HIV-1 in cystic fluid aspirates from six cases of benign cystic lymphoepithelial lesion (BLL) of the parotid gland, a rare disorder affecting HIV-1-infected patients, has been investigated. HIV-1 p24 protein was present at a concentration ranging from 3 to 15 ng/ml, while it was undetectable in the peripheral blood of the same patients. The number of RNA copies of HIV-1 in the cystic fluids was high, ranging from 0.5 x 10(7) to 7.2 x 10(7) RNA copies/ml. BLL cystic fluid aspirates, despite the high level of HIV-1 RNA, were found to contain only a few infectious virions. The low infectivity correlated with the infrequent detection by electron microscopy of complete HIV-1 particles. The pathogenic mechanism leading to virus accumulation in the cystic fluid was studied by immunohistochemistry of tissue sections. p24 protein was associated with DRC-1+/S-100+ follicular dendritic reticulum cells, which were also present within the cystic cavities. Our findings are consistent with the possibility that the large amounts of virus present in the fluid derive from continuous shedding of HIV-1-infected cells from the surrounding lymphoid tissue.

Expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in undifferentiated nasopharyngeal carcinoma (lymphoepithelioma) and in malignant epithelial tumors.

Immunoreactivity for intercellular adhesion molecule-1 (ICAM-1) and for vascular cell adhesion molecule-1 (VCAM-1), two adhesion molecules of the immunoglobulin (Ig) superfamily, was tested and measured on tissue sections from 16 undifferentiated nasopharyngeal carcinomas (U-NPC), 12 keratinizing squamous cell carcinomas (SCCs) of the head and neck region, and 54 malignant epithelial tumors of various origin. Neoplastic cells of all cases of U-NPC were diffusely and intensely stained for ICAM-1 and VCAM-1. Moreover, ICAM-1 messenger RNA (mRNA) and VCAM-1 mRNA were detected by Northern blot analysis of RNA extracts from two tumors. In the other epithelial tumors focal or diffuse staining for ICAM-1 was observed in 40 cases (66%), whereas reactivity for VCAM-1 was detected in a single case of metastatic undifferentiated carcinoma of unknown origin. The biopsy specimens of U-NPC showed variable infiltration by leukocytes, which were positive for the integrins lymphocyte function antigen-1 (LFA-1) and alpha-4/beta-1, the corresponding ligands for ICAM-1 and VCAM-1. The possibility that ICAM-1 and VCAM-1 on neoplastic cells may favor the intratumoral recruitment of leukocytes in a way similar to that occurring in crypt epithelium of the palatine tonsil is discussed.

Surgical approach to isolated mediastinal lymphoma.

With the aim of assessing the role of surgery in the management of isolated mediastinal lymphoma, we have reviewed the data of 123 operations performed on 102 patients (64 with Hodgkin's disease and 38 with non-Hodgkin's lymphoma). One death and four major complications occurred in these patients. Macroscopically radical resection was performed in 14 patients who are free of disease after 1 to 14 years. Debulking resection was performed in five patients: Three are alive after 5 to 11 years and two died after 36 and 40 months. Ten patients (seven with non-Hodgkin's lymphoma and three with Hodgkin's disease) had residual mediastinal masses of more than 2 cm after chemotherapy; to assess the nature of the lesion (fibrosis or residual disease), we subjected these patients to surgical restaging of the mediastinum: Results were negative in seven and positive in three. We conclude that open biopsy is indispensable to obtain good tissue specimens suitable for histologic and immunohistochemical assessment. Biopsy must be performed as a major surgical procedure to avoid reoperation: Mediastinoscopy and sternal splitting incisions proved the most reliable approaches. Locally radical or debulking resection might be considered in selected cases to enhance long-term results.

The prognostic implication of thymoma histologic subtyping. A study of 80 consecutive cases.

In this study the authors have investigated the clinicopathologic correlations in 80 consecutive cases of thymoma in order to establish the clinical usefulness of histologic subtyping of these tumours. All cases were histologically examined and classified according to Salyer and Eggleston and to Marino and Müller-Hermelink classifications. Therefore, thymomas were subtyped as predominantly lymphocytic, mixed and predominantly epithelial and cortical, mixed and medullary, respectively. The frequency of the different histologic subtypes was determined, and histologic findings were related to patients' age, surgical stage, and survival. Through the application of Salyer and Eggleston classification, the three histologic subtypes did not correlate with patients' ages at time of diagnosis, surgical stage as determined by local infiltration, and prognosis as determined by survival curves. On the contrary, when Marino and Müller-Hermelink classification was applied, statistically significant relationships between histologic results and age, surgical stage, and prognosis were demonstrated. These results and their implications are discussed, with special reference to the important problem of histogenesis of thymomas and of their clinicopathologic staging.

Human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) antigens and genome in lymph nodes of HIV-positive patients affected by persistent generalized lymphadenopathy (PGL).

The presence of human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) antigens and genome has been investigated in 50 lymph nodes involved by persistent generalized lymphadenopathy (PGL). All the patients were HIV infected and most of them (42 of 50) also had anti-EBV serum antibodies. At lymph node level, HIV and EBV antigens were studied by immunohistochemistry using monoclonal antibodies directed against viral core proteins. The HIV p24 protein was detected in 43 of 50 lymph nodes within the B-cell germinal centers with a reticular pattern. Few cells with positive results for EBV antigens were found in only 2 of 50 lymph nodes. These rare EBV-positive centrocyte-like cells were mainly located in the germinal centers. The presence of HIV and EBV genome was also studied in lymph nodes involved by PGL, with the use of in situ and Southern blot hybridization. A positive reaction for HIV genome was detected in only 1 of 14 lymph nodes with the Southern blot hybridization, and the presence of EBV genome was never demonstrated in these lymph nodes with the use of both in situ and Southern blot hybridization. The expression of EBV antigens and genome was also investigated in the peripheral blood of 15 patients with PGL in which cells with positive results for EBV antigens were detected in a single case with a frequency of 1 X 10(-4). No evidence of EBV genome was found with the use of the in situ hybridization. These results suggest that EBV is not present in lymph nodes during the PGL phase and that its possible implication in the pathogenesis of acquired immune deficiency syndrome (AIDS)-associated lymphoma might be a late event.

Expression of macrophage-associated antigens in tissues involved by Langerhans' cell histiocytosis (histiocytosis X).

The expression of macrophage antigens KP1, Mac, lysozyme, and alpha-1-antichymotrypsin was investigated on routine paraffin sections from 17 cases of Langerhans' cell histiocytosis (LCH). All the major clinical forms were represented, including single lesions and monosystemic and multisystemic disease. In all the cases, a variable fraction (3-35%) of LCH cells was immunoreactive with KP1 and anti-Mac; the staining pattern was quite typical because the immunoreaction product was often confined to the perinuclear space and the Golgi area. LCH cells containing lysozyme and AACT were detected less frequently; however, in positive cases the percentage of LCH cells immunoreactive for lysozyme and AACT was in the same range as that of KP1-positive cells. On immunostained cytosmears (one case), about 10% of the CD1a-positive cell population was reactive for the macrophage antigens CD14 and PAM-1. No association was noted between the number of KP1-positive cells and the clinical form and/or anatomic site of the lesion. Phagocytic macrophages were significantly and diffusely immunoreactive with KP1 and anti-Mac and for AACT and lysozyme. Multinucleated giant cells with irregular nuclei were frequently observed; these cells were rarely S-100 positive, were consistently stained by KP1 and AACT, and were occasionally anti-Mac positive. The authors' findings suggest that antimacrophage monoclonals, in conjunction with S-100 protein, may represent a useful tool to establish the diagnosis of LCH in paraffin-embedded material.

True thymic hyperplasia: a clinicopathological study.

In this report, we describe the clinicopathological features of 4 patients with true thymic hyperplasia. This controversial thymic lesion has only recently been defined as a variable, often massive enlargement of the thymus characterized by a nearly normal microscopic structure. Our study of 4 patients and review of the literature indicate that true thymic hyperplasia has a well-defined clinicopathological profile: prevalence in children or young male patients, absence of associated autoimmune diseases, and often presence of respiratory distress or peripheral blood lymphocytosis, or both. True thymic hyperplasia should be considered in the differential diagnosis of anterior mediastinal masses in children and young adolescents.

Analysis of prognostic factors and clinicopathological staging of thymoma.

The prognostic value of four clinical variables (age and sex of patients, association with myasthenia gravis, and clinical stage) and histological type was analyzed in 83 consecutive patients with thymoma, histologically classified as cortical, medullary, and mixed. Age, sex, and association with myasthenia gravis did not prove to represent significant prognostic factors; clinical stage and histological type, on the contrary, had a highly significant prognostic value (p less than 0.001). A model of clinicopathological staging, based on both clinical stage and histological type, in which three major prognostic groups are considered is proposed. The degree of significance of this model is higher (p less than 0.0001) than that of clinical stage and histological type considered individually; its validity is further supported by the results of multivariate analysis according to the Cox regression model (p = 0.0001). We think it represents a prognostically valuable approach to the problem of management of thymoma.

Adhesion molecules and lymphocyte recruitment in lymphocytic thyroiditis, thyroid papillary carcinoma and parotid adenolymphoma.

Lymphocytic infiltrates are usually present in chronic lymphocytic thyroiditis, thyroid papillary carcinoma and parotid adenolymphoma. We selected these conditions to investigate the mechanisms of recruitment and organization of lymphocytic infiltrates in extranodal tissues. MoAbs in immunoperoxidase were used to identify the expression of ICAM-1 and VCAM-1 on endothelial cells (EC), and of their ligands LFA-1 and VLA-4 on lymphocytes and accessory cells. VCAM-1 positive EC were rarely observed in thyroids devoid of lymphocyte infiltration. Conversely, EC in chronic lymphocytic thyroiditis and in papillary carcinoma showed positive immunostaining for VCAM-1 and ICAM-1. These findings were associated with the presence of lymphocytes positive for the ligands VLA-4 and LFA-1. The upregulated expression of VCAM-1 on perifollicular capillaries was co-distributed with an accumulation of VLA-4 positive lymphocytes. In adenolymphoma, all EC were ICAM-1 positive, whereas the majority of vessels were VCAM-1 negative. Consequently the majority of lymphoid cells were LFA-1 positive and VLA-4 negative. We suggest that ICAM-1 and VCAM-1 expression on EC play a role in the recruitment of lymphocyte infiltration in chronic lymphocytic thyroiditis and papillary carcinoma. Furthermore, the upregulation of VCAM-1 and VLA-4 in thyroid reactive and neoplastic conditions may be linked to an immune response possibly related to thyroid tissue antigens.

Immunohistochemical characterization of a B-cell signet ring cell lymphoma. Report of a case.

Signet ring cell lymphoma is a non-Hodgkin's lymphoma, characterized by neoplastic lymphoid signet ring cells very similar to epithelial mucin producing cells. We describe here a case of signet ring cell lymphoma in which the immunophenotypic markers of signet ring cells parallel those of plasma cells, being intensively T10+ (CD 38), weakly HLA-DR+, and To15 (CD 22) and T200 (CD 45) negative. The morphologic and immunohistochemical features of the case and the main differential diagnosis are preceded by a review of the literature.

Cystic lymphoepithelial lesions of the parotid gland in HIV-1 infection.

The benign cystic lymphoepithelial lesion (BLL) of the parotid gland is a rare disorder affecting HIV-1-infected patients. Here we describe the clinical and histopathological features of 10 cases of BLL, who presented to our observation between November 1992 and December 1996, before the combination antiretroviral therapy was introduced.

In vitro formation of eosinophil-like colonies by lymph node cells from a human lymphoma.

In vitro culturing of lymph node cells from a human non-Hodgkin lymphoma gave rise to several colonies of eosinophil-like cells. Eosinophil colonies originated from cells that during the first week of culture had a fibroblast appearance and were adherent to plastic. The tissue culture was sacrificed after 14 days. At that time each colony was formed by 20-50 cells with intracytoplasmic peroxidase-positive and eosinophilic granules. Cells comprising the colonies exhibited different degrees of differentiation. Some of the cells (26.6%) were mature eosinophils, the majority (66.8%) resembled eosinophil myelocytes, and some other (4.6%) had a fibroblast appearance. One or two multinucleated giant cells were often present in the center of most of the colonies. These cells contained up to 10 nuclei, which were arranged in a "ring form" or centrally located; giant cells with a single, central, large, multilobed nucleus were also observed. Cells belonging to other myelopoietic lines could not be identified in the tissue culture. Histological examination of the lymph node revealed extensive presence of eosinophils at various degrees of maturation but absence of other myelopoietic lines.

Peripheral T cell lymphoma in adults: morphological and phenotypical study of four cases.

In the present study we investigated the lymph node morphology and distribution of cell surface phenotypes in four cases of adult peripheral T cell lymphoma. Histologically, the tumors were classified as T zone lymphoma, T cell lymphoma with large multilobated nuclei and T cell immunoblastic sarcoma. In the T zone lymphoma the neoplastic lymphocytes were E+ (90%) and exhibited intensive focal staining for acid phosphatase (93%) and acid esterase (92%); the phenotype distribution revealed low expression of the T-3 antigen (49%), selective expression of the T-4 antigen (72%) and poor expression of T-6 (10%) and T-10 antigens (22%). Some of these features are present in normal and in neoplastic immature T cells. In the remaining three cases the majority of lymph node cells were E+ (59-75%), T-3+ (67-80%) and T-8+ (43-55%). A distinctive feature of the T cell immunoblastic sarcoma was the presence of high percentages of DR+ cells (62%; 63%). Thus our results indicate that the morphological heterogeneity of peripheral T cell lymphoma is also paralleled by a variety of surface phenotypes and that phenotype studies may provide a useful contribution to identification and accurate classification of peripheral T cell neoplasms.

[A uterine pecoma: a case report]. / Pecoma uterino: descrizione di un caso.

The authors describe the first ever reported case of a malignant pecoma of the uterus infiltrating the ovary, the tube and two bowel loops. This extremely rare tumour usually shows a benign behaviour and seems to arise from the perivascular epithelioid cells (PEC).