Prostanoid receptor EP1 and Cox-2 in injured human nerves and a rat model of nerve injury: a time-course study.

BACKGROUND: Recent studies show that inflammatory processes may contribute to neuropathic pain. Cyclooxygenase-2 (Cox-2) is an inducible enzyme responsible for production of prostanoids, which may sensitise sensory neurones via the EP1 receptor. We have recently reported that while macrophages infiltrate injured nerves within days of injury, they express increased Cox-2-immunoreactivity (Cox-2-IR) from 2 to 3 weeks after injury. We have now investigated the time course of EP1 and Cox-2 changes in injured human nerves and dorsal root ganglia (DRG), and the chronic constriction nerve injury (CCI) model in the rat. METHODS: Tissue sections were immunostained with specific antibodies to EP1, Cox-2, CD68 (human macrophage marker) or OX42 (rat microglial marker), and neurofilaments (NF), prior to image analysis, from the following: human brachial plexus nerves (21 to 196 days post-injury), painful neuromas (9 days to 12 years post-injury), avulsion injured DRG, control nerves and DRG, and rat CCI model tissues. EP1 and NF-immunoreactive nerve fibres were quantified by image analysis. RESULTS: EP1:NF ratio was significantly increased in human brachial plexus nerve fibres, both proximal and distal to injury, in comparison with uninjured nerves. Sensory neurones in injured human DRG showed a significant acute increase of EP1-IR intensity. While there was a rapid increase in EP1-fibres and CD-68 positive macrophages, Cox-2 increase was apparent later, but was persistent in human painful neuromas for years. A similar time-course of changes was found in the rat CCI model with the above markers, both in the injured nerves and ipsilateral dorsal spinal cord. CONCLUSION: Different stages of infiltration and activation of macrophages may be observed in the peripheral and central nervous system following peripheral nerve injury. EP1 receptor level increase in sensory neurones, and macrophage infiltration, appears to precede increased Cox-2 expression by macrophages. However, other methods for detecting Cox-2 levels and activity are required. EP1 antagonists may show therapeutic effects in acute and chronic neuropathic pain, in addition to inflammatory pain.

CD-34 is expressed by a distinctive cell population in peripheral nerve, nerve sheath tumors, and related lesions.

The pattern of CD-34 antigen (human progenitor cell antigen) immunoreactivity was studied within normal nerve, and a variety of nerve sheath and neuroectodermal tumors. Besides normal nerves, 111 soft tissue tumors were studied, including 17 neurofibromas, 10 neurilemomas, 12 malignant peripheral nerve sheath tumors, 1 melanocytic schwannoma, 21 fibroblastic lesions, 31 fibrohistiocytic lesions, seven neuroectodermal lesions, and 10 miscellaneous tumors. CD-34-positive dendritic cells were consistently identified within the endoneurium of normal nerve, all neurofibromas, dermatofibrosarcomas, and Antoni B (but not Antoni A) areas of neurilemomas. CD-34 was not expressed in the majority (eight of 10 cases) of malignant peripheral nerve sheath tumors. CD-34 was also lacking in all fibroblastic lesions (nodular fasciitis, fibromatosis, keloid, fibrosarcoma) and in neuroectodermal tumors that are not generally considered to show true nerve sheath differentiation (neurotropic melanoma, clear cell sarcoma, neuroepithelioma). We conclude that CD-34 (or a closely related epitope) defines a normally occurring nerve sheath cell that appears to be cytologically and immunophenotypically distinct from a fibroblast and conventional Schwann cell. The antigen can also be localized to benign nerve sheath tumors, but tends to be lost in malignant ones. The consistent presence of CD-34 within all 13 cases of dermatofibrosarcoma protuberans can be used as evidence in support of the view that these lesions are variants of nerve sheath tumors, and distinct from benign fibrous histiocytomas which consistently lack the antigen. Finally, expression of CD-34 by one of three giant cell fibroblastomas reinforces the close relationship between this tumor and dermatofibrosarcoma protuberans.

Aberrant expression of macrophage-associated antigens (CD68 and Ki-M1P) by Schwann cells in reactive and neoplastic neural tissue. Light- and electron-microscopic findings.

The monoclonal antibodies KP1 (CD68), PG-M1 (CD68), and Ki-M1P can be used to detect normal and neoplastic monocytes/macrophages in formalin-fixed, paraffin-embedded tissue. However, systematic investigations undertaken on various tissues have revealed that reactivity with these antibodies is also found in a few cells that do not belong to the mononuclear phagocyte system. The immunoreactivity of normal, reactively altered, and neoplastic Schwann cells with these antibodies was investigated using intact peripheral myelinated nerves, nerves exhibiting Wallerian degeneration, traumatic neuromas, appendixes with neurogenic appendicopathy, granular cell tumors, neurofibromas, and neurogenic sarcomas. The results obtained by light microscopy showed that Schwann cells of nerves with Wallerian degeneration and those in traumatic neuroma, neurofibroma, and granular cell tumor exhibit intracytoplasmic immunoreactivity, which is usually intense, with KP1, Ki-M1P, and PG-M1, but normal myelinated nerves, neurogenic sarcoma, and Schwann cells in neurogenic appendicopathy do not react with these antibodies. No Schwann cells were stained by MAC387 or anti-lysozyme. The site of immunoreactivity with these antibodies was also investigated by electron microscopy. One of the granular cell tumors and macrophages in lymphoid tissue were investigated by the immunogold technique using both pre- and postembedding methods. In granular cell tumor the reaction product was located in phagolysosomes; in macrophages it was found in phagosomes and/or lysosome-like granules. Our findings therefore indicate that immunoreactivity with KP1, Ki-M1P, and PG-M1 can also be expected in cells that do not belong to the mononuclear phagocyte system if they exhibit phagocytosis and/or autophagy.

Tissue reactivity of anti-Leu19.

Monoclonal antibody anti-Leu19, is a marker of natural killer cells. Since reactivity between anti-Leu7, another natural killer cell marker, and small cell neuroendocrine carcinomas has been described, we evaluated the reactivity of anti-Leu19 in 92 neuroendocrine tumours. Frozen sections in each case were immunostained using the avidin-biotin-peroxidase complex method with monoclonal anti-Leu19. We found Leu19 expression in 93% of the cases. We also evaluated 149 other tumours, including adenocarcinomas, undifferentiated large cell carcinomas, lymphomas, melanomas and soft tissue tumours. We found Leu19 expression in 36% (by liberal interpretative criteria), or 29% (by conservative interpretative criteria) of these cases. Thus, while anti-Leu19 appears to be a sensitive marker for neuroendocrine tumours, a lack of specificity limits its practical application in diagnostic histopathology.

Gastrointestinal stromal tumours: correlation of immunophenotype with clinicopathological features.

Stromal tumours of the gastrointestinal tract remain a persistent source of controversy with regard to both their proposed lines of differentiation and the difficulty in predicting their biological behaviour. We have examined 60 cases with a panel of seven antibodies directed at the identification of smooth muscular or neural differentiation. In our hands, 36 per cent of cases showed neural differentiation (although only 6.6 per cent expressed S-100 protein); 31 per cent appeared smooth muscular; 20 per cent manifested bidirectional differentiation; and 13 per cent were negative for all the markers used. Histological appearances do not reliably reflect immunophenotype. We have attempted to correlate immunophenotype with the site of the lesions and with their clinical behaviour. Mean follow-up of 5 years was obtained in 42 cases. Tumours with a neural phenotype have the best prognosis. Gastric tumours expressing both desmin and smooth muscle actin (in the absence of other markers) with up to 4 mitoses per 30 HPF behave in a benign fashion. Larger studies are required to substantiate the value of immunophenotyping this complex group of tumours.

Proliferating cell nuclear antigen expression in central nervous system neoplasms.

Proliferating cell nuclear antigen (PCNA) is a cell-cycle-regulated protein, which can be demonstrated in routinely fixed specimens. Studies on various tissues, cell cultures and neoplasms have shown that PCNA labelling index (LI) correlates with flow cytometry, tritiated thymidine LI, bromodeoxyuridine (BrdU) incorporation and Ki67 LI. PCNA LI may have prognostic value in various neoplasms. The present study concerns PCNA immunostaining in a series of neuroglial tumours. We demonstrate that there is a relation between PCNA LI and histological grade, and between PCNA LI and reported thymidine LI, BrdU LI and Ki67 LI. Pleomorphic xanthoastrocytomas and low-grade astrocytomas had the lowest LI, whereas metastases of small cell lung cancer and medulloblastomas had the highest LI. Glioblastomas sometimes showed a certain degree of intratumoral heterogeneity of distribution of immunostained cells. Intratumoral heterogeneity underscores the critical importance of representative sampling of central nervous system neoplasms for kinetic studies. As expected, PCNA LI are somewhat higher than tritiated thymidine LI, BrdU LI and Ki67 LI because PCNA is a marker of G1, S, G2 and M-phases of the cell cycle and not of S-phase only. In addition, because of its long half-life, PCNA may be detected immunohistochemically in cells that have recently left the cell cycle. The immunohistochemical evaluation of PCNA LI is easy to perform on routinely processed material, allowing retrospective studies. PCNA LI may be a useful tool in grading gliomas. However, its prognostic value must be validated by comparing PCNA LI with the follow-up of the neoplasms, and possibly with the responsiveness to anti-proliferative therapy.

Expression of a new human THY-1 related antigen in Ewing's sarcoma and peripheral neuroectodermal tumors.

Ewing's sarcoma (ES), peripheral neuroectodermal tumor (PNET) and Askin's tumor of the chest wall share a reciprocal chromosomal translocation between the long arms of chromosomes 11 and 22 (q23-24; q12). In the absence of other distinguishing features this specific translocation is regarded as marker of a common and neuroectodermal origin for these rare tumors. A monoclonal antibody (HBA-71) developed in our laboratory has been found to recognize an unique ES and PNET associated antigen, which is also expressed in some normal tissues, including thymus, bone marrow, islets of Langerhans, ependyma and adenohypophysis. It is shown in this study that this HBA-71 antigen is closely related to the murine THY-1 antigens, major cell surface glycoproteins of thymocytes and brain in mice and rat. Both antigens have similar molecular ratios (18,000), amino acid compositions and sensitivity to tryptic digestion, show high cell surface expression, and binding of the appropriate antibodies to HBA-71 antigen triggers proliferation in thymocytes. The HBA-71 epitope may represent a primitive neuroectodermal marker of ES/PNET, or its expression may be directly linked to the reciprocal translocation invariably associated with HBA-71-positive ES and PNET tumors, which maps to the same region of chromosome 11 (q23-24) as the human Thy-1 gene.

Expression of the common acute lymphoblastic leukemia antigen (CD10) in mesenchymal tumors.

The expression of the CD10 antigen, formerly designated as common acute lymphoblastic leukemia antigen and recently identified as neutral endopeptidase, was examined immunohistochemically in 26 benign and in 55 malignant mesenchymal tumors. CD10 expression was found in 4 of 4 leiomyomas, 7 of 10 leiomyosarcomas, 1 of 6 rhabdomyosarcomas, 2 of 2 Triton tumors, 1 of 2 aggressive fibromatoses, 1 of 3 fibrosarcomas, 1 of 4 synovial sarcomas, 1 of 1 giant cell tumors of tendon sheath, 4 of 4 malignant fibrous histiocytomas, 3 of 3 Ewing's sarcomas, and 2 of 3 osteosarcomas. Furthermore, CD10 was expressed consistently in the myoepithelial compartment of 12 fibroadenomas and, in 7 of these cases, in a minor stromal cell population, probably of (myo-) fibroblastic origin. Tumors of adipose tissue (4 lipomas, 5 liposarcomas), tumors of autonomic ganglia (2 ganglioneuromas, 1 ganglioneuroblastoma, 2 neuroblastomas), tumors of peripheral nerves with purely schwannian differentiation (7 malignant schwannomas), and tumors of disputed origin were consistently CD10-negative, however, as were single cases of fibroma and chondrosarcoma. These findings indicate that the expression of CD10 is a frequent but not obligatory feature in some mesenchymal tumors. Therefore CD10 is of value in the differential diagnosis of mesenchymal tumors.

Central nervous system lymphomas and immunodeficiency.

Primary lymphomas of the central nervous system (CNS) may sometimes be associated with some immunological abnormalities, including renal or cardiac transplants, some congenital and acquired immunodeficiencies, immunoinflammatory diseases and immunosuppressive treatments. A relatively high incidence of cerebral lymphomas has been particularly noticed in renal or cardiac transplantation patients and in those with acquired immune deficiency syndrome (AIDS), two conditions which are today observed with increasing frequency. The different congenital and acquired immunodeficiencies associated with cerebral lymphomas and the pathogenetic connections between the two conditions are discussed from a large review of the literature.

Monoclonal antibodies against epitopes on ganglioside GD2 and its lactones. Markers for gliomas and neuroblastomas.

Monoclonal antibodies (mAbs) BW 625 and BW 704, of the IgG3 isotype, bound to immunochemically indistinguishable epitopes on ganglioside II3(Neu-Ac)2-GgOse3-Cer. Despite this fact the mAbs showed a differential binding pattern on human glioma cell lines i.e. immunohistochemical data indicate that the detected epitopes are not identical. Furthermore, either mAb is able to mediate the antibody-dependent cellular cytotoxicity reaction (ADCC) and the human-complement-dependent cytotoxicity reaction (CDC) with epitope-expressing tumor cells. All cryopreserved tissue specimens from gliomas and neuroblastomas were immunohistochemically stained, whereas the other small round cell tumors of childhood, as well as melanomas and small-cell lung carcinomas, were essentially negative. Positive staining of normal cryopreserved tissues was restricted to amyelinic axons, Hassal's bodies and some connective tissue fibers in thymus and the tegumentary epithelium of skin. The high selectivity of mAb BW 704 for gliomas and neuroblastomas, the lack of cross-reactivity with major tissues and the strong ADCC and CDC potential argue for the use of mAb BW 704 in immunotherapy of neuroblastomas and gliomas.

Antibodies as diagnostic probes in the identification of anaplastic round cell malignancy.

The introduction of hybridoma technology has rapidly expanded the role of immunohistochemical analysis in identification of anaplastic malignancy. High affinity antibodies now allow the detection of a wide range of tissue specific antigens so that anaplastic tumours can be accurately classified without the need for costly and often unrewarding, time-consuming ancillary investigations such as electron microscopy, cell culture and chromosomal studies. This review examines the application of a selected panel of commercially available antibodies of proven specificity for the diagnosis of anaplastic round cell tumours. Details of specific examples are provided to illustrate the role of such tissue specific antibodies as diagnostic probes and the approach to anaplastic tumours in various sites is discussed.

Normal and malignant neural cells: a comprehensive survey of human and murine nervous system markers.

Tumor-associated neural markers are finding increased application in diagnostic histopathology and in the development of brain tumor therapy. The major cell-type-specific markers and monoclonal antibodies that identify murine and human neural cells are reviewed in this study. Monoclonal antibodies, raised against fetal and adult neural tissue, neuroectodermal tumor tissue, or cell line immunogens which recognize epitopes on brain tumors are comprehensively described including antigens common to the nervous, hematopoietic, and immune systems. The clinical application of neural cell markers and monoclonal antibodies for the diagnosis, localization, and treatment of neuroectodermal tumors is reviewed.

Phenotyping of 60 cultured human gliomas and 34 other neuroectodermal tumors by means of monoclonal antibodies against glioma, melanoma and HLA-DR antigens.

The reactivity spectrum of three monoclonal antibodies (Mabs) to human malignant glioma, five Mabs to melanomas and one Mab anti-HLA-DR was investigated by an indirect antibody binding radioimmunoassay on a panel of cells derived from 60 glioma lines, including 47 malignant astrocytomas, 11 low-grade astrocytomas and two malignant ependymomas as well on cells from 12 melanoma, three neuroblastoma, three medulloblastoma, two schwannoma, two retinoblastoma, two choroïd plexus papilloma, ten meningioma and 12 unrelated tumor lines. The anti-glioma Mabs BF7 and GE2 reacted preferentially with gliomas, while the anti-glioma Mab CG12 reacted with gliomas, melanomas, neuroblastomas and medulloblastomas. The five anti-melanoma Mabs reacted with gliomas, neuroblastomas and medulloblastomas. The anti-HLA-DR Mab D1-12 reacted with gliomas, melanomas and some meningiomas. On the basis of the data presented, we describe three different antigenic systems; the first one is glioma-associated, the second one is related to differentiation antigens expressed on cells derived from the neuroectoderm and the third is represented by HLA-DR antigens which are expressed not only on B-lymphoblastoid cells but also on melanomas and gliomas.

Occurrence of IgA subclasses (IgA1 and IgA2) in the human nervous system. Correlation with disease.

The occurrence of IgA subclasses in pathological conditions of the nervous system was studied by means of monoclonal antibodies and an indirect immunofluorescence technique. IgA1- and/or IgA2-positive lymphoid (plasma) cells were found in demyelinating diseases comprising multiple sclerosis, Guillain-Barré syndrome, and adrenoleukodystrophy, in various inflammatory diseases, and in tumors, some of which exhibited labeling of tumor cells. Demyelinating and inflammatory diseases with chronic course displayed some prevalence of IgA2-, and tumors some prevalence of IgA1-positive cells. This is the first demonstration of IgA1 and IgA2 in the nervous system.

HNK-1-defined antigen detected in paraffin-embedded neuroectoderm tumors and those derived from cells of the amine precursor uptake and decarboxylation system.

The reactivity of the HNK-1 monoclonal antibody that, besides a subset of hematopoietic cells with natural killer activity, also detects neuroectodermal cells, was screened on 153 human tumors. Immunoperoxidase staining of paraffin sections revealed that HNK-1 detects neuroectoderm-derived cancers and tumors with endocrine activity. Because the antigen detected by HNK-1 is well conserved in paraffin sections, this antibody is of potential diagnostic value in routine histopathology and might help to elucidate the histogenesis of some poorly understood tumors.