Inflammatory cell accumulation in traumatic neuromas of the human lingual nerve.

OBJECTIVE: To quantify the accumulation of inflammatory cells in traumatic neuromas of the human lingual nerve, and to establish any correlation with the patients' reported symptoms of dysaesthesia. DESIGN: Using fluorescence immunohistochemistry, the extent of any chronic inflammatory infiltrate was quantified in human lingual neuroma specimens removed from 24 patients at the time of microsurgical nerve repair. A pan-leucocyte marker (CD45) and a specific macrophage marker (CD68) were used, and comparisons made between neuromas-in-continuity (NICs) and nerve-end neuromas (NENs) in patients with or without symptoms of dysaesthesia. RESULTS: CD68 and CD45 labelling was significantly associated with areas of viable nerve tissue in neuromas and the CD68 labelling was significantly higher in NICs than NENs. CD68 labelling density tended to decrease with increasing time after the initial nerve injury, but this correlation was only significant for labelling associated with viable nerve tissue in NENs. No significant difference was found between the level of CD68 or CD45 labelling in patients with or without symptoms of dysaesthesia. CONCLUSION: This study has demonstrated the presence of inflammatory cells within traumatic neuromas of the human lingual nerve. These cells were found to be closely associated with regions of viable nerve tissue, but there was no correlation with the patients' clinical symptoms.

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.

Expression of melanoma-associated antigens by normal and neurofibroma Schwann cells.

The cell surface antigen distribution on traumatic neuroma Schwann cells and neurofibroma Schwann-like cells was characterized using monoclonal antibodies that define melanoma-associated antigens. Immunofluorescence staining of cultured cells, immunoprecipitation of radioiodinated antigens from cells placed in short-term cultures, and immunoperoxidase staining of frozen tissue sections revealed most of the melanoma-associated antigens tested on traumatic neuroma and neurofibroma Schwann cells and on fetal and adult femoral nerve. The cross-reactivity of the antibodies with neural cells may reflect the common neural crest embryological origin of Schwann cells and melanocytes. Cell sorter analysis of neurofibroma cells using a monoclonal antibody directed against the melanoma nerve growth factor receptor resulted in cell cultures highly enriched for Schwann-like cells which may bear the genetic defect responsible for neurofibromatosis. The antigen detected by this monoclonal antibody is the neurofibroma nerve growth factor receptor and the antibody was a potent inhibitor of nerve growth factor binding to neurofibroma cells.

GFA protein reactivity in nerve sheath tumors: a polyvalent and monoclonal antibody study.

We studied glial fibrillary acidic (GFA) protein immunoreactivity in 30 schwannomas, including two intracerebral examples, 26 neurofibromas and 12 neuromas using the immunoperoxidase method with a polyvalent antiserum (PVAS) and three well-characterized monoclonal antibody (MAb) preparations. Twelve of the schwannomas, including both intracerebral tumors, two of the neurofibromas and none of the neuromas immunostained with PVAS. Except for one schwannoma, all the PVAS-positive tumors were positive with two of the MAb preparations. While both of the intracerebral schwannomas were positive with the third MAb, none of the extracerebral tumors were. Our results suggest that: 1) human nerve sheath tumors contain cells having polypeptides that share epitopes with GFA protein, but 2) these polypeptides differ from astrocytic GFA protein by at least one epitope, and 3) the location of the tumors in relation to the central nervous system may influence GFA protein immunoreactivity.

Neuromas of the appendix. A light-microscopic, immunohistochemical and electron-microscopic study of 20 cases.

The neural origin and even the existence of appendiceal neuromas have been questioned. We have studied 20 examples, 7 discovered during a prospective examination of 26 consecutive routine appendectomy specimens (for an incidence of 27%), 2 selected from random cases, and 11 discovered in a retrospective review of 11 randomly selected cases of appendices diagnosed as "fibrous obliteration." By light-microscopy, appendiceal neuromas appear as a loose proliferation of spindle cells usually in a myxoid background, frequently with entrapped fat and connective tissue and infiltrated by eosinophils. Seventeen were located centrally in the appendix without nodule formation. One was central with nodularity and two were confined to the mucosa. The spindle cells were positive for S-100 protein and neuron-specific enolase in all cases. In 12, serotonin positive cells entrapped in the proliferation were present. In 5 of 11 cases with apparent uninvolved appendix present in the specimen, the number of serotonin cells in the crypts was greater than in normal appendix controls. Two appendiceal neuromas contained somatostatin positive cells. Stains for vasoactive intestinal polypeptide, substance P, neurotensin, bombesin and gastrin were negative. Ultrastructural examination of one case confirmed the presence of a mixture of Schwann cells and cells containing neurosecretory granules. We conclude that appendiceal neuroma is a rather common entity, and that most cases of so-called fibrous obliteration actually represent appendiceal neuroma.

Immunohistochemical detection of epithelial membrane antigen in normal perineurial cells and perineurioma.

The use of epithelial membrane antigen (EMA) as an immunohistochemical marker for normal and neoplastic perineurial cells is described. Normal perineurial cells react strongly for this antigen, which is also expressed by the cells of perineurioma. Instead, neurofibromas and schwannomas only show some peripheral or entrapped layers of EMA-positive cells. In traumatic and Morton's neuromas, bundles of neural fibers are wrapped in layers of EMA-positive perineurial cells. Neurothekeoma and granular cell tumor show no EMA reactivity. The detection of an epithelial marker in perineurial cells is in agreement with the concept of a "perineural epithelium" and seems to support a common embryologic origin for the perineurial cell and the equally EMA-positive arachnoidal cap cell. The availability of an immunohistochemical marker for the perineurial cell provides an easy and convenient tool for the evaluation of the participation of this cell in a variety of pathologic processes.

[Neurogenic appendicopathy - an immunocytochemical study]. / Die neurogene Appendikopathie. Immunzytochemische Untersuchung.

Neurogenic appendicopathy is a frequent (17.8%), non-purulent form of appendicitis. Light microscopy enabled differentiation between an intramucosal variant, a type with central neuroma and neuromuscular proliferations in the submucosa. All nerves within the gut wall were visualized independently of neurotransmitters by immunostaining for neuron-specific enolase. Proliferation of nerve fibres with substance P- and VIP-immunoreactivity was observed in the intramucosal variant and in central neuroma. Moreover, an increase was found in stromal endocrine cells with 5-hydroxy-tryptamine-, somatostatin- and substance P-immunoreactivity. These endocrine stroma cells are considered to be the site of origin of appendix carcinoids. We, therefore, suggest that appendix carcinoids originate in-frequently multicentric-foci of small endocrine cell groups localized within proliferating nerve fibres in the subepithelial stroma, independent of the epithelial layer.

Immunohistochemical recognition of human nerve sheath tumors by anti-Leu 7 (HNK-1) monoclonal antibody.

Using relatively high dilutions of anti-Leu 7 monoclonal antibody and a four-step peroxidase-antiperoxidase (PAP) reaction in paraffin-embedded tissues, we tested the affinity of this antibody to the cells of 47 human nerve sheath tumors and 22 other tumors in which the differential diagnosis with nerve sheath neoplasms is known to arise. Of all the nerve sheath tumors studied 68%, including 80% of the schwannomas, contained anti-Leu 7-positive cells. All 22 non-schwannian neoplasms were entirely negative. Specimens of eight experimental malignant rat schwannomas were also negative for anti-Leu 7 antibody. Our findings suggest that anti-Leu 7 monoclonal antibody is a promising marker that may facilitate the differential diagnosis between human Schwann cell and non-Schwann cell neoplasms.

Possible role of Fc receptors on cells infected and transformed by herpesvirus: escape from immune cytolysis.

Receptors for the Fc portion of nonimmune immunoglobulin G were demonstrated on B103 rat brain neuroma cells infected with herpes simplex virus type 1 (HSV-1) KOS by a radioimmunoassay using 125I-labeled heat-aggregated Fc fragments. Immune F(ab')2 fragments specific for HSV antigens competed efficiently for Fc binding sites, suggesting that the binding of Fc fragments to infected cells is specific for viral cell-surface antigens. It has been suggested that the binding of immune complexes to Fc receptors on the surfaces of tumor cells in vivo plays a role in protecting these cells from immune destruction. In vitro evidence is presented for the ability of aggregated immunoglobulin G molecules bound to cell-surface Fc receptors to protect both HSV-infected and HSV-transformed cells against complement-dependent and cell-mediated immune lysis.

Epithelial membrane antigen expression by the perineurium of peripheral nerve and in peripheral nerve tumours.

Specimens of normal peripheral nerve and a series of peripheral nerve lesions have been immunostained with three different anti-epithelial membrane antigen (EMA) monoclonal antibodies. Sites of EMA immunoreactivity have been confirmed within perineurial cells of peripheral nerve, noted within the capsule of Schwannomas and palisaded encapsulated neuromas, and also detected with traumatic neuromas and plexiform neurofibromas. No expression was detected within simple neurofibromas, diffuse neurofibromas or within malignant Schwannomas. These sites of EMA expression concur with the suggested involvement of perineurial cells in the formation of the particular lesions. The relationship between EMA expression by the perineurium and the piaarachnoid membrane is discussed.