Epstein-Barr virus and AIDS-related primary central nervous system lymphoma. Viral detection by immunohistochemistry, RNA in situ hybridization, and polymerase chain reaction.

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of acquired immunodeficiency syndrome- (AIDS) related primary central nervous system (CNS) lymphoma. Tumors from 16 patients with AIDS-related primary CNS lymphoma, and 1 with concurrent CNS and systemic lymphoma, were evaluated histologically and for the presence of EBV by immunohistochemistry for latent membrane protein, in situ hybridization for EBER1 RNA transcripts, polymerase chain reaction (PCR) for the single copy EBNA1 gene, and PCR for the multiple copy EBV internal repeat region. Histologically, 11 tumors displayed extremely large, bizarre, anaplastic immunoblasts, with prominent nucleoli and multilobated nuclei, resembling Reed-Sternberg (RS) cells and variants. The lymphomas displayed B cell phenotypes by immunohistochemistry. Latent membrane protein was detected in 88% (15/17) of tumors, EBNA1 sequences in 54% (6/11), EBV-internal repeat sequences in 100% (11/11), and EBER1 transcripts in 100% (17/17). All EBNA1-negative tumors lacked RS-like cells. Latent membrane protein immunohistochemical staining was limited to a minority of tumor cells, and was most often positive in RS-like, immunoblastic large cells. In situ hybridization for EBER1 message demonstrated EBV in the majority of tumor cells, which displayed a wide range of sizes and variable nuclear morphology. We conclude that EBV can be detected in all AIDS-related primary CNS lymphomas, and that EBER1 in situ hybridization is currently the best technique for detecting virus. The presence of atypical immunoblasts (RS-like cells) with high levels of latent membrane protein in many of these tumors may suggest the emergence of a common, virally-determined phenotype in AIDS-related lymphomas of brain.

Meningeal meningiomatosis in a child: case report.

We report a child with multifocal meningeal lesions demonstrating mixed meningiomatous histologic features. This lesion appears to have evolved over seven years, starting with a brief episode of garbled speech, nausea, and headache at 4.5 years of age. The child was then asymptomatic until 9 when she presented with bilateral leg weakness, in addition to her prior presenting symptoms and communicating hydrocephalus. Meningeal biopsies of two lesions were performed 18 months later. Immunohistochemistry and electron microscopy were needed to substantiate the histologic diagnosis. Radiation therapy to the craniospinal axis and corticosteroids were of some benefit, but more aggressive therapeutic modalities became necessary. The nosology of this lesion is discussed.

Hemineglect and seizures in Binswanger's disease: clinical-pathological report.

The range of clinical effects from ischaemic damage to white matter in Binswanger's disease has not been fully characterised. Although focal deficits and seizures occur frequently, superficial infarcts often coexist, making the cause of these symptoms unclear. The case of a 69 year old woman is described who presented with acute left sided weakness and hemispatial neglect, followed a year later by electrographically documented seizures originating from the right hemisphere. Interim examinations showed bilateral pyramidal signs and mild intellectual decline. Serial CT and MRI studies showed bilateral diffuse ischaemic lesions of the cerebral white matter and old left sided lacunar infarcts but no evidence of acute infarction. Post-mortem examination showed gliosis and demyelination of the deep white matter which spared the subcortical arcuate fibres; this is consistent with Binswanger's disease. The neocortex was normal. This case and previous reports indicate that focal symptoms typically referable to the grey matter, including hemineglect and seizures, may occur as a manifestation of subcortical ischaemic injury to white matter in Binswanger's disease.

Progressive multifocal leukoencephalopathy in patients with human immunodeficiency virus.

Lesions of progressive multifocal leukoencephalopathy (PML) in patients infected with the human immunodeficiency virus (HIV) often have mononuclear cell infiltrates so intense that they obscure the nature of the lesion. This response may be especially prominent in stereotactic biopsies of contrast-enhancing areas. Of 10 consecutive PML lesions biopsied stereotactically, three were markedly, two were moderately, and five were mildly inflamed. There were few to no enlarged oligodendrocytic nuclei with inclusions in the markedly and moderately inflamed lesions. We investigated all biopsies with immunoperoxidase, DNA in situ hybridization, polymerase chain reaction, and Southern immunoblot methodologies for toxoplasmosis and the following viruses: JC, cytomegalovirus, herpes simplex viruses I and II, and human T-cell lymphotropic viruses I, II, and III. We confirmed the presence of JC virus in each lesion; polymerase chain reaction revealed HIV genome only in one. Inflammatory PML lesions in HIV+ patients do not reflect co-infection with toxoplasmosis or viruses commonly seen in these patients. The mononuclear cells are primarily T lymphocytes. Patients with severely inflamed PML lesions, whether HIV+ or not, often show stabilization of symptoms with or without antiviral treatment and have longer lengths of survival than patients with less inflamed lesions.

Cholesterol emboli neuropathy.

We report the clinical and pathologic features of a patient with peripheral neuropathy that was the first clinical expression of cholesterol emboli syndrome (CES). Biopsy of skeletal muscle and peripheral nerve revealed cholesterol clefts in lumens of small arteries, necrotizing arteritis, and severe degeneration of peripheral and intramuscular nerves. At autopsy, the peripheral nervous system was extensively affected by similar changes. We conclude that (1) peripheral neuropathy may be the initial manifestation of CES. Presumably, deposition of cholesterol leads to arteritis. (2) The underlying pathology of CES neuropathy is chronic axonal degeneration, possibly due to chronic ischemia of epineurial arteries. (3) Muscle biopsy is important in the antemortem diagnosis of CES. Nerve biopsy may show involvement of epineurial vessels. (4) CES may resemble polyarteritis nodosa clinically and pathologically. (5) CES may be under-recognized and should be included in the differential diagnosis of any neuropathy of uncertain cause, particularly when there is a history of vascular catheterization, or severe aortic atherosclerosis.

Immunohistochemistry and proliferative activity in Lhermitte-Duclos disease.

We have evaluated a recurrence of Lhermitte-Duclos disease by immunohistochemistry for Purkinje cell markers and proliferative activity (proliferating cell nuclear antigen), by electron microscopy and for DNA ploidy (image analysis). While most of the abnormal neurons in the lesion appear to be derived from granule cells, several Purkinje cell specific polyclonal and monoclonal antibodies, including L7, PEP 19 and calbindin, labeled a minor subpopulation. Staining with monoclonal antibodies to proliferating cell nuclear antigen and measuring cell DNA index and ploidy with a cell image analyzer revealed no proliferative activity. Electron microscopy findings were similar to those previously reported. In spite of its recurrence, our findings support the notion that Lhermitte-Duclos disease is malformative, not neoplastic, and that the characteristic neurons are derived predominantly but not exclusively from a non-Purkinje cell source, probably the granule cell.

Intracerebral Hodgkin's disease in a human immunodeficiency virus-seropositive patient.

Intracerebral involvement of Hodgkin's disease (HD) is rarely described, with only 42 cases in the literature. Since the outbreak of the acquired immune deficiency syndrome (AIDS) epidemic, there has been an increasing number of human immunodeficiency virus (HIV)-infected (HIV+) persons who have diffuse non-Hodgkin's lymphoma and, more recently, atypical aggressive HD. The authors report the case of a patient with a history of intravenous drug abuse (IVDA) and Stage IVB HD who, after a drug-induced clinical remission, had intracerebral mixed-cellularity HD. This appears to be the first report of intracerebral HD in a person who is HIV+.

Concomitant Creutzfeldt-Jakob and Alzheimer diseases.

We report a 69-year-old female with cerebral and cerebellar symptomatology of 15-month duration. At autopsy, both panencephalopathic Creutzfeldt-Jakob and plaque-predominant Alzheimer diseases were found. Plaque amyloid was exclusively of the beta/A4 type, but abundant abnormal protease-resistant protein was identified by Western blot analysis of brain extracts.

Specific antimononuclear phagocyte monoclonal antibodies. Application to the purification of dendritic cells and the tissue localization of macrophages.

3C10 and 1D9 are two related monoclonal antibodies that specifically identify human mononuclear phagocytes in a large number of sites, including blood monocytes, alveolar macrophages, and macrophages in tissue sections of spleen, lymph node, and skin. The antigen persists on monocytes cultured for greater than 4 wk, but it is not found on giant cells. The 3C10-1D9 determinant is carried by a 55 kD polypeptide, is expressed at approximately 40,000 copies per monocyte, and is protease sensitive. The antigen is clearly different from HLA-class II or Ia-like antigens that have been studied with a new monoclonal 9.3F10. The 9.3F10 antigen is found on B cells, dendritic cells and monocytes; is protease resistant, and occurs on a 33-29 kD doublet typical of class II products. The 3C10 monoclonal provides a clear distinction between human mononuclear phagocytes and dendritic cells. First, monocytes and lymphocytes can be eliminated from plastic-adherent mononuclear cells using 3C10, complement, and two previously described cytotoxic antibodies, BA-1 (anti-B cell) and Leu-1 (anti-T cell). As a result, the trace dendritic cell component of blood can be enriched to considerable purity (65-75%) and yield. Second, immunocytochemical staining of tissue sections reveals that 3C10+ macrophages are anatomically segregated from dendritic cells. Large numbers of 3C10+ cells are found in red pulp of spleen and in regions surrounding lymphatic channels of lymph node. However, 3C10+ macrophages are scarce in white pulp of spleen and the lymphocyte-rich cortex of node that are the sites where dendritic cells are localized. 3C10+ cells in skin are found in the dermis, particularly in leprosy infiltrates, but the Langerhans' cells of epidermis are 3C10-. The distinctive localization of macrophages and dendritic cells is consistent with their respective functions as effector and accessory cells in the immune response.

Relative efficacy of human monocytes and dendritic cells as accessory cells for T cell replication.

Monocyte-specific monoclonal antibodies (7) were used to compare the efficacy of monocytes and dendritic cells as accessory or stimulator cells for human T cell replication. Both unfractionated and plastic-adherent mononuclear cells were first treated with a cytolytic antimonocyte antibody that kills greater than 95% of monocytes but not dendritic cells. When tested as stimulators of the mixed leukocyte reaction (MLR) and of oxidative mitogenesis (the proliferation of T cells modified with sodium periodate), the monocyte-depleted cells had normal or enhanced stimulatory capacity. Monocyte-depleted mononuclear cells also proliferated normally to soluble antigens (Candida albicans, tetanus toxoid), even under limiting conditions of cell dose, antigen dose, and culture time. Adherent blood mononuclear cells were next separated into monocyte-enriched and -depleted components using fluoresceinated antimonocyte antibody and the cell sorter. The depleted fraction (less than 2% monocytes by esterase staining and by cytology) contained the dendritic cells and exhibited at least 75% of the accessory activity. The monocyte-rich fraction (approximately 97% esterase positive) stimulated the MLR and oxidative mitogenesis weakly, and was comparable in potency to nonadherent cells. Cell-specific antibodies and complement were also used to prepare dendritic cells that were thoroughly depleted of monocytes and lymphocytes. The dendritic cells (70-80% pure) were potent stimulators of the allogeneic MLR, syngeneic MLR, and tetanus toxoid response, being active at stimulator to responder ratios of 1:100 or less. Taken together with previous studies (1, 2), these experiments indicate that the dendritic cell is the major stimulator of T cell replication in man. The contribution of class II products of the major histocompatibility complex (7) was then evaluated with a new monoclonal, 9.3F10. Accessory function was dramatically inhibited if cells bearing class II antigens were killed with 9.3F10 and complement, or if class II molecules were blocked by the addition of 9.3F10 Fab to the culture medium. The expression of 9.3F10 class II products was therefore studied on purified monocytes and dendritic cells. Most if not all cells in both populations reacted with 9.3F10, and each population exhibited approximately 150,000 125I-Fab 9.3F10 binding sites per cell. Since Ia+ dendritic cells are active accessory cells, but Ia+ monocytes are not, class II products are necessary but not sufficient for the stimulation of T cell proliferation in man.

The cutaneous infiltrates of leprosy: cellular characteristics and the predominant T-cell phenotypes.

We report on the characteristics of cells in the cutaneous lesions and blood of 21 patients with lepromatous, tuberculoid, and intermediate forms of leprosy. A large proportion of the infiltrates in lepromatous lesions consist of macrophages heavily parasitized with Mycobacterium leprae. The T cells in the lesions are devoid of OKT4/Leu 3a-positive ("helper") cells and consist almost exclusively of OKT8/Leu 2a-positive ("suppressor") populations. In contrast, the tuberculoid infiltrates contain well-organized epithelioid and giant-cell granulomas and only remnants of bacilli, and the predominant T cell is from the OKT4/Leu 3a-positive subset. In both tuberculoid and lepromatous infiltrates, T cells and macrophages expressed HLA-DR antigen. No marked alteration in the distribution of blood T-cell phenotypes was noted. We conclude that there is a marked difference between T-cell subsets in lepromatous and tuberculoid infiltrates, which may influence the microbicidal activity of macrophages in the lesions.

Human dendritic cells. Enrichment and characterization from peripheral blood.

Previous studies demonstrated that lymphoid tissues of mice and rats contain small numbers (less than 1 percent of nucleated cells) of dendritic cells (DC) with special cytologic, surface, and functional properties. We show here that similar DC represent 0.1-0.5 percent of human peripheral blood mononuclear cells. DC can be enriched to 20-60 percent purity by a multistep procedure analogous to that used in mice. Adherent peripheral blood mononuclear cells are cultured overnight, and the released cells are depleted of monocytes and B cells by readherence to plastic, rosetting with erythrocytes coated with anti-human IgG, and centrifugation in dense albumin columns. Enriched DC have similar cytologic features to rodent DC by light and electron microscopy. DC express HLA, and HLA-DR and the leukocyte-common antigens. They lack phagocytic capacity, receptors for antibody-coated and neuraminidase-treated erythrocytes, surface and intracellular Ig, esterase, peroxidase, and azurophilic granules. DC do not react with several monoclonal antibodies directed to phagocytes (OKM 1, "mac-1," 63D3, and 61D3) and T cells (OKT 3, 6, 8). Unlike the mouse, human DC express complement receptors. When maintained in culture for 4 d, human DC did not give rise to either B cells or monocytes. Therefore, DC identified by cytologic criteria are distinct from other leukocytes. Enriched populations of DC have been compared to fractions enriched in monocytes, B cells, and T cells in three functional assays: stimulation of the primary allogeneic mixed leukocyte reaction, stimulation of the primary syngeneic MLR, and accessory function for the proliferation of periodate- modified T cells. In each case, the DC fraction was 10-fold or more active than other cell fractions. We conclude that DC circulate in man, and represent the principal cell type required for the initiation of several immune responses.