Autologous humoral response to human gliomas and analysis of certain cell surface antigens: in vitro study with the use of microcytotoxicity and immune adherence assays.

In 25 patients with intracranial gliomas, the autologous humoral response was studied in vitro with the use of microcytotoxicity (MC) and immune adherence (IA) assays. Antibodies were detected to autologous cultures in 44% of the cases by MC and in 50% by IA. These positive responses occurred in statistically different groups of patients, which suggested that different functional types of antibody were involved. Direct testing and absorption experiments showed that antibody was not significantly directed against autologous fibroblasts. Autologous cytotoxic antibodies were detected by 67% of astrocytoma cases and in only 10% of patients harboring a glioblastoma, the most anaplastic tumor of the glioma series. By means of the IA assay, absorption experiments were performed with the use of adult and fetal brains and cultures of autologous and allogeneic gliomas and fibroblasts. In this serologic system, the types of antigenic expression of a human glioma could be categorized as follows: 1) highly restricted glioma antigen(s), 2) common glioma antigen(s), 3) neurectoderm-derived antigen(s), and 4) brain and fibroblast-associated oncofetal antigen(s). The common glioma antigen and oncofetal antigen appeared to be qualitatively different, and the glioma antigen was expressed in uncultured tumor tissue.

Pharmacokinetics and tumor localization of 131I-labeled anti-tenascin monoclonal antibody 81C6 in patients with gliomas and other intracranial malignancies.

We previously have reported that radioiodinated anti-tenascin monoclonal antibody 81C6 exhibits therapeutic potential against both s.c. and intracranial human glioma xenografts in athymic mice and rats. Herein we report the selective tumor localization of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies. Nine patients were simultaneously administered 5-50 mg of 131I-labeled 81C6 and 1-2 mg of 125I-labeled 45.6, an isotype-matched control monoclonal antibody. The blood clearance half-time for 81C6, normalized to that of 45.6 in the same patient, appeared to decrease with 81C6 protein dose. Gamma camera images obtained at 1 to 3 days exhibited increased uptake of 131I in regions corresponding to tumor with varying degrees of contrast to surrounding normal brain. Biopsy specimens of tumor and normal brain were obtained and analyzed histologically for tumor content. The average uptake of 81C6 in tumor ranged from 0.6 to 4.3 x 10(-3)% of the injected dose per gram. In patients receiving 20-50 mg of 81C6, the average tumor-to-normal-brain ratio was 25:1 with ratios as high as 200:1 seen in some samples. Localization indices were calculated by normalizing the uptake of 81C6 per gram tumor to the uptake of 81C6 per gram blood and dividing by the same ratio for 45.6 control monoclonal antibody. Localization indices for muscle and brain were about 1, in contrast to up to five for tumor. These studies demonstrate that the tumor uptake of 131I-labeled 81C6 in patients with gliomas and other intracranial malignancies is due to specific processes.

Cryptic cerebellopontine angle neuroglial cyst presenting with hemifacial spasm.

Hemifacial spasm (HFS) is commonly caused by a vascular loop compressing the Root Exit Zone (REZ) of the facial nerve. We report a case of HFS caused by a vascular loop that was abnormally displaced by a neuroglial cyst not seen in Magnetic Resonance Imaging (MRI). Microvascular decompression (MVD) was planned and the patient underwent a key-hole retromastoid posterior fossa exposure. A cystic lesion was found in the cerebellopontine angle (CPA), located around the seventh and eighth cranial nerves extending from the porous acousticus to the brainstem REZ of the facial nerve. The cyst wall was partially excised revealing the region of the neurovascular conflict. MVD of the facial nerve was performed with immediate postoperative complete resolution of the patient's symptoms.

Phenotypic analysis of four human medulloblastoma cell lines and transplantable xenografts.

An extensive panel of monoclonal antibodies (MAb) and monospecific antisera reactive against neuroectodermal-, neuronal-, glial-, and lymphoid-associated antigens, extracellular matrix, HLA, and cell-surface receptors was used to characterize the phenotype of four continuous, karyotypically distinct medulloblastoma cell lines and transplantable xenografts. All four cell lines demonstrated significant reactivity with anti-neuroectodermal-associated MAb. No apparent pattern of reactivity with anti-lymphoid MAb was seen; notably, there was a uniform absence of detectable Thy-1. Review of the complete antibody reactivity profile revealed a dichotomy between lines TE-671 and Daoy and lines D283 Med and D341 Med, which have been previously shown to express neurofilament protein in culture and xenografts, and to exhibit neuroblastic morphological features in biopsy and xenograft tissue sections. TE-671 and Daoy reacted with the MAb directed against tenascin, epidermal growth factor (EGF) receptor, HLA-A,B epitopes, beta 2-microglobulin and 5/8 of the glioma-associated antigens, but did not react with the anti-neurofilament protein (NFP) MAb. D283 Med and D341 Med expressed NFP but did not react with MAb against tenascin, EGF receptor, HLA-A,B epitopes, beta 2-microglobulin or 6/8 and 7/8 (respectively) of the glioma-associated antigens. The observed phenotypic differences provide a conceptual framework for investigating basic differences in the biological behavior of medulloblastoma. Moreover, the subdivisions can be evaluated for prospective value in tissue diagnosis, cerebrospinal fluid cytology and antibody-mediated imaging and therapy.

Central demyelination of the Vth nerve root in trigeminal neuralgia associated with vascular compression.

We have examined the ultrastructure of the trigeminal sensory nerve root in three patients with medically intractable trigeminal neuralgia. In one patient, the nerve root was sandwiched between a large vein and a small pontine artery, in the others compression was due to marked dolichoectasia of a verterbal artery. Because these were not amenable to microvascular decompression, a caudal rhizotomy was performed, by excising a short inferior segment of nerve root in the region of indentation. In all cases, examination revealed a zone of chronic demyelination in the proximal (centrally myelinated) part of the root, near its junction with peripheral nerve. The zone of demyelination contained closely packed axons without intervening glial cytoplasm. Also present were small numbers of thinly myelinated axons. In some cases a single thin myelin sheath encircled several adjacent axons that were still in close apposition. These findings indicate that the trigeminal neuralgia associated with vascular compression is due to demyelination. The demyelination is associated with some evidence of remyelination. The latter phenomenon may account in part for the long periods of remission, especially during the initial period after the onset of trigeminal neuralgia. The partly aberrant nature of the myelination within the region of vascular compression may contribute to the persistence of symptoms in some patients after decompressive surgery.

Quantitative distribution of 131I-labelled monoclonal antibodies administered by the intra-ventricular route.

In a preliminary study in one patient [111In]DTPA was injected into the lateral ventricle and at the same time [99mT]DTPA into the lumbar sac. The 111In distributed freely throughout the CSF but the concentration of 99mTc in the ventricles remained consistently low. In the second phase of the study three patients with tumours confined to the neuraxis were treated with 20-50 mCi 131I-labelled monoclonal antibodies administered into the lateral ventricle via Ommaya reservoirs. Quantitative distribution of radio-labelled antibody was assessed at intervals up to 8 days post injection. In each case there was rapid distribution to all parts of the neuraxis with 38-68% of total CNS counts remaining in the head and 13-39% in each of the upper and lower half spine areas. The t1/2 for total CNS counts were 31.5, 19.8 and 15.5 h. There was no clear evidence of tumour localization and no neurological toxicity. These patients demonstrate that radiolabelled monoclonal antibodies can be given safely via Ommaya reservoirs and that in order to obtain optimal distribution throughout the CSF this should be the preferred method of administration. Further trials in patients with minimal disease are warranted.

Comparative localization of glioma-reactive monoclonal antibodies in vivo in an athymic mouse human glioma xenograft model.

Radioiodinated murine monoclonal antibodies (Mabs) 81C6, Me 1-14, C12, D12, and E9, made against or reactive with human gliomas but not normal brain, and Mab UJ13A, a pan-neuroectodermal Mab reactive with normal human glial and neural cells, were evaluated in paired label studies in the D-54 MG subcutaneous human glioma xenograft model system in nude mice. Following intravenous injection in the tail vein of mice bearing 200-400 mm3 tumors, specific localization of Mabs to tumor over time (6 h-9 days) was evaluated by tissue counting; each Mab demonstrated a unique localization profile. The comparison of localization indices (LI), determined as a ratio of tissue level of Mab to control immunoglobulin with simultaneous correction for blood levels of each, showed Mabs 81C6 and Me 1-14 to steadily accumulate in glioma xenografts, maintaining LI from 5-20 at 7-9 days after Mab injection. Mab UJ13A peaked at day 1, maintaining this level through day 2, and declining thereafter. Mabs D12 and C12 peaked at days 3 and 4, respectively, and E9 maintained an LI of greater than 3 from days 3-9. Percent injected dose localized/g of tumor varied from a peak high of 16% (81C6) to a low of 5% (Me 1-14 and UJ13A). Immunoperoxidase histochemistry, performed with each Mab on a battery of primary human brain neoplasms, revealed that Mabs 81C6 and E9, which demonstrated the highest levels of percent injected dose localized/g of tumor over time, reacted with antigens expressed in the extracellular matrix. This finding suggests that extracellular matrix localization of antigen represents a biologically significant factor affecting localization and/or binding in the xenograft model used. The demonstration of significant localization, varied kinetics and patterns of localization of this localizing Mab panel warrants their continued investigation as potential imaging and therapeutic agents for human trials.

Monoclonal antibody 2C5: a marker for a subpopulation of small neurones in rat dorsal root ganglia.

Monoclonal antibody 2C5 labels a subset of dorsal root ganglion neurones in the rat. The cell sizes of these neurones fall within the range for the small dark cell population and the antibody labels between a half and two-thirds of the neurones in this size range. A subpopulation of small neurones was also labelled in the trigeminal and vagal ganglia. Other sites of immunoreactivity in the central nervous system are the region of the substantia gelatinosa of the spinal cord, fibres in Lissauer's tract, the tractus solitarius and the tuberculum olfactorium. These sites are consistent with the antigen being expressed by the central processes of primary afferent neurones. It is suggested that the size distributions of 2C5-positive dorsal root ganglion neurones and the pattern of 2C5 immunoreactivity within the spinal cord indicate that the labelled cells may be neurones with peripheral C fibers. Outside the nervous system the antigen is expressed in a number of specific cell types within a variety of organs. These include some pancreatic acinar cells, parietal cells of the gastric mucosa, some cells in taste buds, Leydig cells of the testis, scattered cells in lymph nodes and lung alveoli, some renal tubules, the epithelial lining of the fallopian tube, the epithelium covering the ovary and certain cells in the basal layer of the epidermis.

Immunohistological signposts in central nervous system tumours with neuronal differentiation.

25 neuronal tumours with a panel of antibodies were studied and it was found that vimentin was present in 15 tumours. It was also found in a few cells within rosettes. PGP 9.5 showed a somatic pattern of staining with nuclear and perinuclear positivity in 23. Neurofilament reactivity was found in 14. Retinal S-antigen was detected only in one medulloblastoma, 3/4 pineal tumours and 2/2 retinoblastomas. Reactivity, for synaptophysin was present in 2/5 medulloblastomas, 3/10 neuroblastomas and 2/2 retinoblastomas. GFAP was demonstrated in scattered tumour cells in 4/5 medulloblastomas. Two of these were the only tumours featuring bipolar differentiation whilst it was unipolar in the remainder. The significance of these findings in relation to the ontogeny of these tumours is discussed.

Mononuclear cell infiltrate, HLA-Dr expression and proliferation in 37 acoustic schwannomas.

Frozen sections from 37 schwannomas of the VIII nerve were reacted with a panel of monoclonal antibodies to macrophage, lymphocyte, HLA-Dr invariant chain and nuclear proliferation antigens. A moderate number of macrophages was demonstrated in 96% of tumours. CD8- and CD4-lymphocytes were detected in slightly smaller numbers in up to 87% and 23% of tumours respectively. B-lymphocytes were present in only 2/32 cases and NK-cells were absent from all 16 cases tested. HLA-Dr antigen was expressed by macrophages in most cases and by tumour cells in 13/24 tumours. These findings may represent evidence for a degree of cellular immune response. Occasional cells featuring nuclear proliferation were detected in 15/27 cases.

Haemangioblastoma: histological and immunohistological study of an enigmatic cerebellar tumour.

Paraffin-embedded blocks of 36 cerebellar haemangioblastomas were reacted with a panel of antibodies including glial fibrillary acidic protein, vimentin, epithelial membrane antigen, cytokeratin, Factor VIII, a neuroendocrine marker and with Ulex europaeus. agglutinin The main histological features, apart from the characteristic large abnormal vessels, were a prominent reticulin network, a cystic architecture and cellular and nuclear polymorphism. Two cell types were identified: endothelial and stromal. Twenty tumours were positive for glial fibrillary acidic protein because of included or reactive astrocytes as well as positive stromal cells. Vimentin was positive in all tumours with a diffuse distribution and a somatic pattern; blood vessels, stromal cells and reactive astrocytes were strongly positive. Factor VIII and Ulex europaeus agglutinin reactivity were present in a similar pattern of staining in endothelium and in five cases there were stromal cells that were positive with the latter. We were not able to ascertain the histogenesis of the stromal cell, which remains enigmatic.

Immunoglobulin gene rearrangement and antigenic profile confirm B cell origin of primary cerebral lymphoma and indicate a mature phenotype.

Six cases of primary cerebral lymphoma were immunophenotyped and analysed by Southern blotting to determine the clonality and lineage of these neoplasms. Molecular analysis showed that they were of B cell origin, and the rearrangement of both heavy and light chain immunoglobulins in malignant cells showed that they were monoclonal populations of mature B cells. The characterisation of the genetic configuration of the immunoglobulin genes in these lymphomas is important because the ability to distinguish between primary lymphoma of the central nervous system and other malignant cerebral tumours has important implications for treatment and survival.

Immunocytochemical study of the cellular immune response in meningiomas.

Twenty four meningiomas (17 benign and seven "atypical" were reacted with a panel of monoclonal antibodies to macrophages, lymphocytes, and HLA DR antigens. All the tumours contained macrophages but these cells were more numerous in the atypical meningiomas. Lymphocytes, almost exclusively of the CD8 subtype, were also present in 70% of benign meningiomas and in all atypical meningiomas and were more abundant in the latter. B lymphocytes were present in minimal numbers in three atypical meningiomas and in one benign meningioma. CD4 positive T lymphocytes were present in small numbers in one benign meningioma and in moderate numbers in one atypical meningioma. HLA DR antigen expression on tumour cells was present in about 60% of both tumour groups. The numbers of macrophages and T and CD8 lymphocytes in meningiomas seem to be related to atypical histological features, and the presence of these cells raises questions about host immune response and the relation of this to prognosis.

Immunohistological diagnosis of central nervous system tumours using a monoclonal antibody panel.

A panel of seven monoclonal antibodies has been used to characterise 164 cerebral and spinal tumours. These reagents have enabled rapid and accurate diagnosis of tumours to be made, particularly in cases where standard techniques have proved equivocal. On the basis of characteristic antigenic profiles of tumours, it has been possible to distinguish between gliomas, meningiomas, schwannomas, medulloblastomas, neuroblastomas, choroid plexus tumours, various metastatic deposits, and primary brain lymphomas. The reagents used in the study comprise antibodies binding to (a) most neuroectodermally derived tissues and tumours (UJ13A), (b) fetal brain and tumours of neuroblastic origin (UJ181.4), (c) schwannomas, normal and neoplastic neurones (UJ127.11), (d) glial cells (FD19), (e) epithelial cells (LE61), and (f) leucocytes (2D1). Some reagents, such as antibody A2B5, were less effective as diagnostic markers than originally suggested by previously described specificity. This monoclonal antibody reacted with both neuroectodermal and epithelial derived tumours. The panel of monoclonal antibodies was most useful in the diagnosis of tumours composed of small round cells, particularly lymphoma and neuroblastoma, but the pattern of reactivities allowed most of the central nervous system tumours to be accurately classified. This approach was a valuable adjunct to conventional histological techniques in about 20% of the cases examined.

Second-look surgery for incompletely resected fourth ventricle ependymomas: technical case report.

OBJECTIVE AND IMPORTANCE: The prognosis for patients with ependymomas is related to the adequacy of surgical clearance. It is, however, often not possible to obtain a macroscopically complete resection of tumors arising in the posterior fossa. This may be because of the involvement of structures, the sacrifice of which would result in unacceptable morbidity, or because of metastatic lesions at diagnosis. For those patients in whom initial surgery was incomplete, elective second-look surgery may allow more complete clearance of tumor. INTERVENTION: We have performed second-look surgery for fourth ventricle ependymomas in five patients: two women, aged 26 and 27 years, and three male patients, aged 4 months, 19 months, and 18 years. The 19-month-old male patient underwent early second-look surgery without receiving any interim chemotherapy. Second-look surgery on the other four patients was performed after they had received chemotherapy. No additional major morbidity was associated with the subsequent surgery, which achieved macroscopically complete clearances in four of the five patients. Three of four patients who underwent macroscopically complete resections were well, without clinical or radiological evidence of recurrent tumor, at 23, 25, and 34 months after their second operations. The 10-month-old patient who underwent early second-look complete resection relapsed locally at 33 months after surgery. Complete resection was not possible in one patient who had progressive tumor 8 months after second-look surgery. CONCLUSION: For patients in whom complete excision of fourth ventricle ependymomas is not possible at initial surgery, second-look procedures may enable macroscopic clearance to be achieved with little morbidity. A larger study is needed to evaluate this approach to treatment.

Pathological findings associated with trigeminal neuralgia caused by vascular compression.

Vascular compression of the trigeminal nerve root accounts for more than 80% of intractable cases of trigeminal neuralgia, but the pathogenesis is still debated. The authors report the ultrastructural changes in the trigeminal nerve root of a patient with trigeminal neuralgia, at the point of compression by a large, medially placed petrosal vein, and compare these with the findings in six cases of trigeminal neuralgia not related to vascular compression. Vascular compression of the trigeminal nerve root was associated with focal loss of myelin and close apposition of the demyelinated axons with few intervening astrocytic processes. No inflammatory cells were present. Immunoelectron microscopy for glial fibrillary acid protein confirmed that astrocyte processes were largely confined to the periphery of the lesion. Of the other six rhizotomy specimens, only one, from a patient with multiple sclerosis, showed demyelination with intervening astrocyte processes, perivascular lymphocytes, and lipid-laden macrophages. These findings support the hypothesis that ephaptic transmission plays a role in the pathogenesis of trigeminal neuralgia related to vascular compression.

Cerebral distribution of immunoconjugate after treatment for neoplastic meningitis using an intrathecal radiolabeled monoclonal antibody.

A detailed autopsy and autoradiographic study was performed after the death of a patient undergoing intrathecal, antibody-guided irradiation for carcinomatous meningitis. The results demonstrated tumor cells infiltrating the surface meninges and a severe astrocytic reaction associated with oedema in the periventricular and brain stem subpial white matter. This was not seen in cortical or other gray matter structures. Autoradiographic examination correlated well, demonstrating isotope within the oedematous areas of the white matter in addition to the expected concentration in the leptomeningeal layers. These findings are discussed in the context of antibody binding to tumor tissue and the possible benefits conferred in the treatment of infiltrating tumor cells.

Teflon-induced granuloma following treatment of trigeminal neuralgia by microvascular decompression. Report of two cases.

The authors report two cases of Teflon-induced granuloma occurring as a result of microvascular decompression using Teflon wool for the treatment of trigeminal neuralgia (TN). Teflon, which is used to separate a compressing vessel from the root entry zone (REZ) of the trigeminal nerve at the brainstem, is presumed to be an inert material. In the two cases reported here, however, Teflon induced a foreign body reaction at the REZ, causing recurrence of TN. The patients' pain was cured by complete decompression or partial sensory rhizotomy of the trigeminal sensory root at reoperation. Teflon-induced granuloma has occurred in 1.3% of the authors' series of 155 patients with TN treated using microvascular decompression. Recommendations for avoiding this complication are offered.

Congenital astroblastoma: an immunohistochemical study. Case report.

Astroblastoma is a rare type of glial tumor, usually occurring in older children and young adults. It has a distinctive histological appearance that is characterized by a radiating arrangement of tumor cells that form perivascular pseudorosettes. The authors report only the second case of astroblastoma presenting in congenital form. Following subtotal tumor resection, the infant received 10 courses of chemotherapy consisting of vincristine, etoposide, and carboplatinum. Evidence is presented for a tumor response to chemotherapy, a previously unreported observation. The child is alive 2.5 years after diagnosis with satisfactory functional status. Immunohistological and ultrastructural features of this tumor are presented. The discussion focuses on the biology, natural history, and management of this unusual neoplasm.

Cytotoxic antibody responses in astrocytoma patients. An improved allogeneic assay.

Early diagnosis of brain tumors may be facilitated by a microcytotoxicity assay which the authors have used to detect a humoral immune response against an allogeneic glioblastoma cell line. Sixty-seven of 82 serum samples (82%) from astrocytoma patients elicited significant cytotoxicity, while only six of 65 samples (9%) from normal blood-bank donors demonstrated a similar response. Positive results were more frequently obtained in lower-grade astrocytomas. Meningiomas, acoustic schwannomas, pituitary adenomas, and metastatic tumors were positive in variable numbers of cases. A small series of serum samples were platelet-absorbed to insure that cytotoxicity was not merely due to histocompatibility antigens, and seven of eight samples, when retested on the target cell line, remained significantly positive. The assays were performed under strictly monitored conditions that afforded optimum reliability and minimal experimental variability. As the specificity of this test increases, it may lead to early detection of astrocytomas.