John E. Greenlee

Type IIa ('anti‐Hu') antineuronal antibodies produce destruction of rat cerebellar granule neurons in vitro

We reacted dispersed cultures of newborn rat cerebellar granule cells with serum, purified IgG, and CSF from patients with type Ha (“anti-Hu”) antibody response accompanying paraneoplastic neurologic syndromes. All type Ha sera, IgGs, and CSFs, but not those of normal or cancer controls, produced bright nuclear immunofluorescence of cultured granule neurons. Type Ha serum and CSF labeled proteins of 35-42 kd in rat granule cell blots, identical in molecular weight to proteins labeled by type IIa antibodies in blots of human granule cells. IgGs eluted from the 35-42 kd band in blots of rat granule cells labeled proteins of similar molecular weights in blots of human granule cells and produced typical type IIa immunostaining of human cerebellar sections. Human IgG could be identified in nuclei and cytoplasm of neurons incubated for 72 hours with 2/4 type IIa sera tested, but not with normal sera. Type IIa sera or IgGs from 4/7 patients produced specific lysis of rat granule cells in the presence of complement, as compared with controls using normal serum or heat-inactivated complement. Prolonged (7-day) incubation of cultures with type IIa antibody without complement also resulted in specific lysis, whereas incubation with normal serum or serum from neurologically normal patients with small-cell carcinoma of the lung did not. Rat granule cell cultures provide a valuable in vitro system with which to study the interaction of type IIa antibody with neurons. The present study provides the first reported evidence that type IIa antibodies may cause cell injury directly, in the absence of lymphocyte-mediated immune response.

Uptake of systemically administered human anticerebellar antibody by rat Purkinje cells following blood-brain barrier disruption

Paraneoplastic cerebellar degeneration accompanying gynecological or breast malignancies is frequently associated with an autoantibody response, termed “type I” or “anti-Yo” directed against cytoplasmic antigens of cerebellar Purkinje cells. The role of this antibody response in the pathogenesis of paraneoplastic cerebellar degeneration is unknown; however, it is also not known whether anti-Purkinje cell antibodies from the systemic circulation bind to target Purkinje cell antigens under the conditions of brain inflammation and blood-brain barrier disruption, which are frequently present at the onset of cerebellar symptoms. Inbred Lewis rats received intraperitoneal injections of type I or normal IgG in the setting of blood-brain barrier disruption induced by adoptive transfer of experimental allergic encephalomyelitis (EAE) and were killed after 24, 48, and 96h. Brains of these animals were studied histologically for evidence of EAE and immunohistochemically for binding of human or endogenous rat IgG to target neurons. Rat IgG was detected around vessels and in Purkinje cells of all animals studied. Human IgG was detected around vessels of all animals. In animals examined 96 h after receiving type I human IgG, human IgG was identified within processes of Purkinje cells and within occasional Purkinje cell bodies. Uptake of type I IgG by other cell types was not observed, and neuronal uptake of IgG was not seen in brains of animals receiving normal human IgG. Our data demonstrate that circulating type I IgG is internalized by cerebellar Purkinje cells in the setting of blood-brain barrier disruption and suggest a mechanism by which an antibody response directed against cytoplasmic antigens of Purkinje cells may reach target antigens at the onset of paraneoplastic cerebellar degeneration.

Immunoperoxidase labeling of rat brain sections with sera from patients with paraneoplastic cerebellar degeneration and systemic neoplasia

Sera from patients with systemic cancer found by immunofluorescence staining to have antibodies to human cerebellar cell populations were reacted with vibratome sections of rat cerebellum and examined by peroxidase-antiperoxidase (PAP) methods. Seven patients with clinically or pathologically confirmed paraneo-plastic cerebellar degeneration and two neurologically normal patients with high titers of anticerebellar antibodies were studied. Sera from all antibody-positive patients, but not from controls, produced intense staining of brain sections. Sera from patients with ovarian adenocarcinoma reacted predominantly with Purkinje cells and neurons within brainstem nuclei. Sera from patients with oat cell carcinoma and one patient with ductal carcinoma of the breast produced nuclear and cytoplasmic staining of neurons throughout the central nervous system. Serum from a patient with Hodgkins disease labeled the peripheries of Purkinje cells and Golgi II cells. Serum from a patient with mixed mesodermal sarcoma of the ovary labeled Purkinje cells, basket cells, and scattered astrocytes. Staining of extraneural tissues was not observed. This study confirms the presence of antineural antibodies in patients with systemic neoplasia with and without paraneoplastic cerebellar degeneration and suggests that the antigens recognized by this antibody response may vary with the associated neoplasm.

Association of anti-Yo (type I) antibody with paraneoplastic cerebellar degeneration in the setting of transitional cell carcinoma of the bladder: detection of Yo antigen in tumor tissue and fall in antibody titers following tumor removal.

Anti‐Yo (type I) autoantibodies reactive with Purkinje cell cytoplasmic antigens of 34 and 62 kd are found in the serum and cerebrospinal fluid of patients with paraneoplastic cerebellar degeneration associated with cancer of the ovary, uterus, adnexa, or breast. Anti‐Yo antibody response is rarely associated with other tumors. Here, we present a patient who developed paraneoplastic cerebellar degeneration and anti‐Yo antibody response in association with transitional cell carcinoma of the bladder. The presence of anti‐Yo antibodies was confirmed by immunofluorescence assay and by Western blot analysis against both Purkinje cell lysates and the CDR62 fusion protein. Yo antigen was demonstrated in sections of the patients tumor. Antibody titers fell after tumor removal. Transitional cell carcinoma should be considered in patients presenting with subacute cerebellar degeneration and anti‐Yo antibody response in whom ovarian, adnexal, uterine, or breast cancer cannot be detected. Ann Neurol 1999;45:805–809

Cerebellar Purkinje cells incorporate immunoglobulins and immunotoxins in vitro: implications for human neurological disease and immunotherapeutics

BackgroundImmunoglobulin G (IgG) antibodies reactive with intracellular neuronal proteins have been described in paraneoplastic and other autoimmune disorders. Because neurons have been thought impermeable to immunoglobulins, however, such antibodies have been considered unable to enter neurons and bind to their specific antigens during life. Cerebellar Purkinje cells - an important target in paraneoplastic and other autoimmune diseases - have been shown in experimental animals to incorporate a number of molecules from cerebrospinal fluid. IgG has also been detected in Purkinje cells studied post mortem. Despite the possible significance of these findings for human disease, immunoglobulin uptake by Purkinje cells has not been demonstrated in living tissue or studied systematically.MethodsTo assess Purkinje cell uptake of immunoglobulins, organotypic cultures of rat cerebellum incubated with rat IgGs, human IgG, fluorescein-conjugated IgG, and rat IgM were studied by confocal microscopy in real time and following fixation. An IgG-daunorubicin immunotoxin was used to determine whether conjugation of pharmacological agents to IgG could be used to achieve Purkinje cell-specific drug delivery.ResultsIgG uptake was detected in Purkinje cell processes after 4 hours of incubation and in Purkinje cell cytoplasm and nuclei by 24-48 hours. Uptake could be followed in real time using IgG-fluorochrome conjugates. Purkinje cells also incorporated IgM. Intracellular immunoglobulin did not affect Purkinje cell viability, and Purkinje cells cleared intracellular IgG or IgM within 24-48 hours after transfer to media lacking immunoglobulins. The IgG-daunomycin immunotoxin was also rapidly incorporated into Purkinje cells and caused extensive, cell-specific death within 8 hours. Purkinje cell death was not produced by unconjugated daunorubicin or control IgG.ConclusionPurkinje cells in rat organotypic cultures incorporate and clear host (rat) and non-host (human or donkey) IgG or IgM, independent of the immunoglobulins reactivity with Purkinje cell antigens. This property permits real-time study of immunoglobulin-Purkinje cell interaction using fluorochrome IgG conjugates, and can allow Purkinje cell-specific delivery of IgG-conjugated pharmacological agents. Antibodies to intracellular Purkinje cell proteins could potentially be incorporated intracellularly to produce cell injury. Antibodies used therapeutically, including immunotoxins, may also be taken up and cause Purkinje cell injury, even if they do not recognize Purkinje cell antigens.

Treatment of Paraneoplastic Cerebellar Degeneration

Opinion statementParaneoplastic cerebellar degeneration is an uncommon autoimmune disorder characterized clinically by progressive, ultimately incapacitating ataxia and pathologically by destruction of cerebellar Purkinje cells, with variable loss of other cell populations. The disorder is most commonly associated with gynecological and breast carcinomas, small cell carcinoma of the lung, and Hodgkin’s disease and in most cases comes on prior to identification of the underlying neoplasm. The hallmark of paraneoplastic cerebellar degeneration is the presence of an immune response reactive with intracellular proteins of Purkinje or other neurons or, less commonly, against neuronal surface antigens. Evidence-based treatment strategies for paraneoplastic cerebellar degeneration do not exist; and approaches to therapy are thus speculative. Diagnosis and treatment of the underlying neoplasm is critical, and characterization of the antibody response involved may assist in tumor diagnosis. Most investigators have initiated treatment with corticosteroids, plasma exchange, or intravenous immunoglobulin G. Cyclophosphamide, tacrolimus, rituximab, or possibly mycophenolate mofetil may warrant consideration in patients who fail to stabilize or improve on less aggressive therapies. Plasma exchange has been of questionable benefit when used alone but should be considered at initiation of treatment to achieve rapid lowering of circulating paraneoplastic autoantibodies. Because the course of illness is one of relentless neuronal destruction, time is of the essence in initiating treatment. Likelihood of clinical improvement in patients with longstanding symptoms and extensive neuronal loss is poor.

Anti-Hu antibodies in Merkel cell carcinoma

Anti‐Hu antibody is an antineuronal autoantibody found in a subset of patients with paraneoplastic neurological disease. The antibody was first associated with small cell carcinoma of the lung and is most often used as a marker for this neoplasm in patients presenting with suspected paraneoplastic syndromes. Here we report a patient with a multifaceted neurological disorder in the setting of Merkel cell carcinoma. The patients serum contained antibodies against the Hu antigen, and the expression of the Hu antigen was demonstrated in the patients tumor.

Anti-Yo Antibody Uptake and Interaction with Its Intracellular Target Antigen Causes Purkinje Cell Death in Rat Cerebellar Slice Cultures: A Possible Mechanism for Paraneoplastic Cerebellar Degeneration in Humans with Gynecological or Breast Cancers

Anti-Yo antibodies are immunoglobulin G (IgG) autoantibodies reactive with a 62 kDa Purkinje cell cytoplasmic protein. These antibodies are closely associated with paraneoplastic cerebellar degeneration in the setting of gynecological and breast malignancies. We have previously demonstrated that incubation of rat cerebellar slice cultures with patient sera and cerebrospinal fluid containing anti-Yo antibodies resulted in Purkinje cell death. The present study addressed three fundamental questions regarding the role of anti-Yo antibodies in disease pathogenesis: 1) Whether the Purkinje cell cytotoxicity required binding of anti-Yo antibody to its intraneuronal 62 kDa target antigen; 2) whether Purkinje cell death might be initiated by antibody-dependent cellular cytotoxicity rather than intracellular antibody binding; and 3) whether Purkinje cell death might simply be a more general result of intracellular antibody accumulation, rather than of specific antibody-antigen interaction. In our study, incubation of rat cerebellar slice cultures with anti-Yo IgG resulted in intracellular antibody binding, and cell death. Infiltration of the Purkinje cell layer by cells of macrophage/microglia lineage was not observed until extensive cell death was already present. Adsorption of anti-Yo IgG with its 62 kDa target antigen abolished both antibody accumulation and cytotoxicity. Antibodies to other intracellular Purkinje cell proteins were also taken up by Purkinje cells and accumulated intracellularly; these included calbindin, calmodulin, PCP-2, and patient anti-Purkinje cell antibodies not reactive with the 62 kDa Yo antigen. However, intracellular accumulation of these antibodies did not affect Purkinje cell viability. The present study is the first to demonstrate that anti-Yo antibodies cause Purkinje cell death by binding to the intracellular 62 kDa Yo antigen. Anti-Yo antibody cytotoxicity did not involve other antibodies or factors present in patient serum and was not initiated by brain mononuclear cells. Purkinje cell death was not simply due to intraneuronal antibody accumulation.

Bilateral hippocampal encephalitis caused by enteroviral infection

Nonpolio enteroviral encephalitis usually presents as a diffuse, generalized encephalitis. Focal cerebral involvement by nonpolioviruses is uncommon, and neuroradiologic studies in these cases are usually normal. The authors present a case of a 5-year-old male with an acute encephalitic illness and bilateral lesions of the hippocampi on magnetic resonance imaging. Enteroviral nucleic acids were detected in the cerebrospinal fluid by the reverse transcription polymerase chain reaction. The findings suggest that enteroviral infection should be considered in the differential diagnosis of acute bilateral hippocampal encephalitis in patients in whom polymerase chain reaction fails to demonstrate the presence of herpes simplex virus.

Neurologic consequences of autoimmune polyglandular syndrome type 1

Background: Autoimmune polyglandular syndrome type 1 (APS-1) is a rare autosomal recessive disorder that is chiefly characterized by polyendocrinopathy, chronic mucocutaneous candidiasis, and ectodermal dystrophy. The neurologic complications of this disorder have not been well characterized. Method: The authors report a patient with a previously undescribed autoimmune cerebellar degeneration occurring in association with APS-1 and review the literature regarding the neurologic complications of this disorder. Results: This 24-year-old woman with APS-1 presented with gait ataxia associated with band-like hyperintense signal abnormalities of both cerebellar hemispheres and a unique antibody to cerebellar Purkinje cells and brainstem neurons. At age 9, she had C. Miller Fisher syndrome, from which she had fully recovered. Conclusions: Autoimmune neurologic disease may develop with autoimmune polyglandular syndrome type 1. Neurologic disease may also result from the associated endocrinopathies (hypoparathyroidism, hypothyroidism, diabetes mellitus), vitamin deficiency (vitamins B12 and E), and celiac sprue.