Utility of anti-Hu antibodies in the diagnosis of paraneoplastic sensory neuropathy

Anti-Hu antibodies (Hu-Abs) were positive in 40 patients with paraneoplastic sensory neuropathy (PSN) and in 1 patient with idiopathic sensory neuropathy in a series of 126 patients who presented with clinical features suggestive of PSN. The specificity of Hu-Abs was 99% and the sensitivity was 82%. Nine (18%) PSN patients were Hu-Ab-negative, and their sera did not harbor other specific anti-neuronal or anti-ganglioside antibodies. Small cell lung carcinoma (SCLC) was the leading neoplasm in the Hu-Ab-positive (79%) and Hu-Ab-negative (44%) groups. This study confirms the value of Hu-Abs for the diagnosis of PSN and SCLC and also emphasizes that in patients with possible PSN, the absence of Hu-Abs does not exclude cancer, particularly in those patients with risk factors for SCLC.     

Intravenous immunoglobulin treatment in paraneoplastic neurological syndromes with antineuronal autoantibodies

OBJECTIVE: To evaluate the effect of intravenous high dose human immunoglobulin (IVIg) therapy on the clinical course and autoantibody titres of patients with neurological paraneoplastic syndromes. METHODS: Twenty two patients with paraneoplastic encephalomyelitis and sensory neuronopathy syndrome associated with anti-Hu antibodies (18) or paraneoplastic cerebellar degeneration (PCD) with anti-Yo antibodies (four), were treated with 1-26 (mean 5.8) cycles of IVIg. The Rankin scale was used to evaluate the response. RESULTS: The only serious toxicity was one case of haemolytic anaemia. Twenty one patients were evaluable for therapeutic response. One patient, with subacute sensory neuronopathy (SSN), improved for at least 15 months, 10 remained stable (eight with anti-Hu and two with anti-Yo antibodies), and 10 deteriorated (eight with anti-Hu and two with anti-Yo antibodies). In seven of the 10 patients who stabilised, the syndrome had already made a plateau when the treatment was started but three patients (one with anti-Hu and two with anti-Yo antibodies) who had still been progressing stabilised for six, eight, and more than 48 months, including one patient with SSN who achieved stabilisation when the neurological dysfunction was only moderate (Rankin scale = 3). Another patient with SSN and initial stable response worsened when IVIg was reduced and improved when it was increased. No significant predictive factors of outcome could be identified but improvement or stabilisation was more frequent in patients with isolated involvement of the peripheral nervous system (62%) than in patients with evidence of CNS damage (37%) at the onset of treatment. Stabilisation in patients with CNS involvement was only achieved when the neurological dysfunction was already severe (Rankin scale > 3). The titres of autoantibodies did not change significantly. CONCLUSION: Treatment with IVIg at the doses given in the present protocol was not effective in paraneoplastic CNS syndromes associated with antineuronal antibodies. The role of this regime in the treatment of SSN should be further evaluated.     

Neurologic paraneoplastic syndromes

Several neurologic paraneoplastic disorders are believed to be caused by an autoimmune reaction against antigen(s) co-expressed by tumour cells and neurons. Of the paraneoplastic syndromes, the evidence for an autoimmune etiology is strongest for the Lambert-Eaton myasthenic syndrome, in which autoantibodies downregulate voltage-gated calcium channels at the presynaptic nerve terminal. For other syndromes, including cerebellar degeneration, multifocal encephalomyelitis, sensory neuronopathy, limbic encephalitis, opsoclonus-myoclonus, stiff person syndrome, and retinal degeneration, the autoimmune theory is supported by the presence of specific antineuronal antibodies. These antibodies serve as a useful diagnostic tool, but their actual role in causing neuronal injury and clinical disease remains unclear. Further understanding of immunopathogenesis awaits successful experimental models. Among different syndromes, a varied proportion of patients shows neurologic improvement with immunosuppressive treatments; it is likely that many patients have already suffered irreversible neuronal injury at the time of diagnosis.     

Neurologic paraneoplastic syndromes with neurotologic manifestations

Evidence supports the hypothesis that autoimmune mechanisms are operational in the etiopathogenesis of certain neurologic paraneoplastic syndromes (PNSs), including paraneoplastic encephalomyelitis (PEM) and paraneoplastic cerebellar degeneration (PCD). The antibodies (Anti-Hu and Anti-Yo), the antigens (Hu and Yo), and complementary DNA clones encoding Hu and Yo, central to PEM and PCD, respectively, have been isolated. In contrast, the antigens, and antibodies if any, involved in autoimmune cochleovestibular dysfunction remain unknown. The temporal bone histopathology and neuropathology of 2 patients, 1 with PEM and 1 with PCD, who developed signs and symptoms of cochleovestibular dysfunction, are reviewed and contrasted to the literature. It is concluded that both auditory and vestibular symptomatology and pathologic alterations can be seen in association with neurologic PNSs and that studies using the antigens and antibodies involved in neurologic PNSs may provide a new perspective on the investigation of autoimmune cochleovestibular dysfunction.     

Steroid-dependent anti-Hu negative paraneoplastic encephalomyelitis and small cell lung carcinoma

Oslerus osleri tracheobronchitis was diagnosed in 4 young dogs following endoscopic visualization of tracheal nodules and identification of larvae in airway cytologic samples. All dogs improved when ivermectin was administered (200-400 micrograms/kg body weight); however, most (3/4) required serial treatments in order to achieve long-term resolution of clinical signs.     

Cell-mediated autoimmunity in patients with Wegener's granulomatosis (WG)

Despite the well described infiltration of cells of the cellular immune system in vasculitic lesions and the granuloma formation in patients with WG, the role of T cell-mediated autoimmunity in WG is not clear. Reports of T cell proliferation in response to neutrophil azurophilic granule proteins are contradictory. In this study we have assessed the proliferation of T cells of WG patients to purified proteinase 3 (PR3) and to total azurophilic granule proteins in two different assays. In addition to the classical proliferation assay with isolated peripheral blood mononuclear cells, we have used a whole blood proliferation assay. In both assays we found proliferative responses to PR3 in patients with WG. The number of patients reacting to the azurophilic granule extract was higher than the patients reacting to the purified PR3, suggesting that other autoantigens may also be involved. We have identified epitopes of PR3 that may be potential targets of class I-restricted T cell responses in the context of HLA-A*0201, the most common MHC class I molecule. These epitopes were determined by the binding of synthetic PR3 peptides to HLA-A*0201 on the antigen-processing defective cell line, T2. In addition, T cell lines were established from tissue biopsies, obtained from WG patients, and assessed for cytolytic reactivity against T2 cells, preloaded with synthetic PR3 peptides. We conclude that T lymphocytes of WG patients have increased proliferative responses to purified PR3 and to a larger extent to non-fractionated proteins of azurophilic granules of polymorphonuclear neutrophilic leucocytes (PMN).     

Immune surveillance: paraneoplastic or environmental triggers of autoimmunity

Autoimmunity associated with tumor cell development seems an important mechanism by which to prevent progression to clinical cancer. In this brief review, tumor autoantigens associated with paraneoplastic syndrome, non-HLA-associated organ-specific autoimmune diseases, and the highly cell-specific autoimmune eradication of the islet beta cells in type 1 diabetes are compared and discussed. It is suggested that autoreactivity is important in preventing tumor formation; however, it may be at the expense of the development of autoimmune disease. Although the cytotoxic T lymphocytes (CTL) induction by HLA class I has been studied and used in clinical trials, little is understood about the initiation and HLA class II mediated induction of an immune response to neoplastic cells. This induction apparently takes place because paraneoplastic disorders are often due to an immune response to the tumor cell resulting in a cross-reactivity with a normally expressed autoantigen on a remote nontumor-associated target cell. The problem of immune surveillance to eradicate neoplasm or downregulate pathological autoimmunity are therefore closely related phenomena. An improved understanding of immune mediated tumor suppression should therefore greatly benefit immunotherapy of type 1 diabetes, and the two areas of research would benefit from an interdisciplinary endeavor.     

Molecular cloning of a new unc-33-like cDNA from rat brain and its relation to paraneoplastic neurological syndromes

Anti-CV2-autoantibodies from patients with paraneoplastic neurological syndromes were used to purify protein(s) related to this disease. A novel cDNA, c-22, was obtained by PCR with primers based on amino-acid sequence of peptides obtained from this protein and rat brain cDNA as template. The deduced amino-acid sequence of c-22 shows homology to the Unc-33 gene from C. elegans in which mutations lead to defects in neuritic outgrowth and axonal guidance and cause uncoordinated movements of the nematode. Several consensus sites for putative protein kinase C phosphorylation were found, suggesting that the c-22 gene product may be a phosphoprotein. Northern hybridizations show that the apparently unique 3.8-kb mRNA of c-22 is present in rat brain tissue and its expression is developmentally regulated: the levels of C-22 mRNA, detectable in brain at embryonic day 17 (E17), increase up to post-natal day 7 (P7) and decline rapidly to an almost undetectable level in adult.     

Therapy for paraneoplastic neurologic syndromes in six patients with protein A column immunoadsorption

BACKGROUND: Paraneoplastic neurologic syndromes, although rare, cause significant morbidity and mortality. They are thought to be immunologically mediated, but to date those involving the central nervous system (CNS) have not been particularly responsive to immunologic therapy. The use of the novel immunomodulator, protein A immunoadsorption, was explored to address this question. METHODS: Six patients with neurologic paraneoplastic syndromes were treated with this technique, using the "off line" method. Two hundred fifty ml of plasma was perfused through a column containing protein A covalently attached to a silica matrix. The plasma was then returned to the patient. RESULTS: Five of the patients responded to the therapy, with complete and durable responses in three patients with opsoclonus-myoclonus, objective, though transient, improvement in one patient with paraneoplastic brainstem encephalitis associated with a Merkel cell tumor, and stabilization and partial improvement in one patient with paraneoplastic limbic encephalitis. The patient without response developed a cutaneous vasculitis after the second treatment, and therapy was discontinued. CONCLUSIONS: This therapy appears beneficial for a number of paraneoplastic syndromes, most dramatically in the opsoclonus/myoclonus syndrome.     

Antibodies of the anti-Yo and anti-Ri type in the absence of paraneoplastic neurological syndromes: a long-term survey of ovarian cancer patients

PURPOSE: To determine the association between lipids, microalbuminuria and systemic blood pressure. Urinary albumin excretion rate (AER) was determined in timed overnight urine samples by radioimmunoassay. Microalbuminuria was defined when two out of three urine samples had AER ranging 20-200 micrograms/min. Lipids were determined by colorimetric methods (total cholesterol, HDL cholesterol and triglycerides). METHODS: Fifty patients with insulin dependent diabetes mellitus (28 females, 22 males) aged 21.9 +/- 7 years and with diabetes duration of 6.8 +/- 5.8 years attending the outpatients diabetes clinic were studied cross-sectionally. RESULTS: Microalbuminuria was present in 12% of our patients. A high systolic blood pressure (SBP) was found in microalbuminuric patients (p = 0.003). No difference concerning serum lipids were found in comparison between normo and microalbuminuric patients, although 20% of all patients had increased cholesterol and LDL cholesterol and 4% had high HDL cholesterol and triglycerides levels. Stepwise multiple regression analysis showed that SBP was the only significant independent variable to influence AER (r = 0.42 r2 = 0.18 p = 0.002). CONCLUSION: Although in our study, microalbuminuria was associated only with SBP, the independent alteration of lipids in young IDDM patients must be considered as a possible additional risk factor for cardiovascular disease.     

HuR, a novel target of anti-Hu antibodies, is expressed in non-neural tissues

Paraneoplastic encephalomyelitis (PEM) is characterized by a diverse set of clinical signs that are limited to the nervous system. The serologic hallmark of PEM is the presence of circulating autoantibodies, collectively referred to as 'anti-Hu,' which immunoreact specifically with members of the Elav protein family. Until recently, the ELAV antigens were only detected in neurons, thus strongly supporting a role for anti-Hu antibodies in the selective neural tissue injury in PEM. The identification of HuR, however, a new member with a broad, non-neural pattern of RNA expression, raises several fundamental questions regarding PEM. First, why are non-neural tissues spared in PEM? Second, why is PEM predominantly associated with neuroendocrine tumors? To begin addressing these questions, we sought to determine whether the antibody response to HuR differs from the neural-specific counterparts in patients with PEM, and to characterize the protein expression pattern of this novel antigen in peripheral tissues and tumors. Using sera from 11 patients with Hu-positive PEM, we found that the majority of samples (73%) were weakly or non-reactive for recombinant HuR on Western blot, in contrast to consistently strong immunoreactivity with the neural-specific members HuD and Hel-N1. We also demonstrate that HuR is expressed at the protein level in both non-neural tissues and non-neuroendocrine tumors. These findings suggest that immunoreactive differences among Elav family members may contribute to the neural-restrictive pattern of tissue injury in patients with PEM.     

Immunobiological approach to spinocerebellar degeneration--anti-Purkinje cell antibodies in paraneoplastic cerebellar degeneration

We analyzed the antibodies against cerebellum in five patients with paraneoplastic cerebellar degeneration (PCD). Four patients were found to have autoantibodies against rat brain, first one to cerebral 250 kd and 110 kd and cerebellar 110 kd proteins, second one to cerebral and cerebellar 98 kd and 68 kd proteins, third one to cerebellar 58 kd protein and fourth one to 58 kd protein especially in the cytoplasm and nucleus of Purkinje cells. We isolated a cDNA clone from a human cerebellar library to identify the target antigen for fourth antibody. Homology searches revealed a similarity with the zinc finger proteins. Zinc finger proteins are considered to regulate gene expression. Therefore, degeneration of this protein by its antibody may affect the synthesis of proteins in Purkinje cell and may cause cerebellar degeneration.     

A paraneoplastic mixed bullous skin disease associated with anti-skin antibodies and a B-cell lymphoma

BACKGROUND: The full spectrum of bullous diseases associated with underlying cancers remains to be fully defined. OBSERVATION: We describe a patient with a mixed bullous disease exhibiting combined features of cicatricial pemphigoid and pemphigus and associated with a B-cell lymphoma producing an IgM paraprotein to intercellular antigens in human skin. The patient had the clinical features of cicatricial pemphigoid and the histologic and immunofluorescence abnormalities of both cicatricial pemphigoid and pemphigus. These included oral and cutaneous erosions; ocular scarring; subbasal and acantholytic intraepidermal bullae; and circulating and tissue-fixed basement membrane zone and intercellular antibodies. The antibodies were directed to a 140-kd antigen in dermal extracts of skin split with 1 mol/L of sodium chloride and to antigens with approximate molecular weights of 150, 180, 230, and 285 kd in the dermal extract. In contrast to paraneoplastic pemphigus, the intercellular antibodies did not react to mammalian bladder. The intercellular antibodies were of the IgM class and were associated with the paraprotein produced by the malignant B cells. CONCLUSIONS: We believe that this condition represents a novel bullous disease, which we refer to as paraneoplastic mixed bullous disease. This condition illustrates that distinct bullous diseases are associated with paraneoplastic syndromes and that at least one possible mechanism for such eruptions is the production of anti-skin antibodies by malignant B cells.     

Dynamic course of neurological syndromes in very young children with the history of intrauterine growth retardation

90 infants with intrauterine growth retardation (IGR) and 100 normal infants (control group) were followed up from 5 days till 3 years of life. In IGR infants there was a more frequent combination of several neurologic syndromes, an early manifestation of motor disorders (from the very moment of birth), a delay of neuro-psychic development (during the first year of life), a tendency to development of moderate hydrocephalus by the age of 6 months. Autonomic-visceral disorders in them were mostly characterized by the symptoms of abaissement, but not of irritation.     

Anti-GD1a ganglioside antibodies in peripheral motor syndromes

High titers of anti-GD1a antibodies have been found in patients with Guillain-Barre syndrome or motor neuropathy. To determine the possible diagnostic relevance of these antibodies, we measured serum anti-GD1a IgG and IgM antibodies by enzyme-linked immunosorbent assay in 195 patients with different motor syndromes and in 335 control subjects. Moderately high antibody titers (1/1,280-1/5,120) were occasionally found in patients with chronic inflammatory demyelinating polyneuropathy (5%), multifocal motor neuropathy (18%), lower motor neuron disease (3.8%), or amyotrophic lateral sclerosis (1.8%) and in immunological control subjects (1.2%), while titers of 1/20,480 or higher were only found in 2 patients with Guillain-Barre syndrome (IgG in both) and 2 with motor neuropathy and IgM lambda monoclonal gammopathy improving with immunotherapy. In both motor neuropathy patients and the Guillain-Barre syndrome patient who were retested during recovery, anti-GD1a titers decreased concomitantly with clinical improvement. High anti-GD1a antibody titers may be found in several motor syndromes but only markedly increased anti-GD1a titers are strictly associated with potentially treatable dysimmune neuropathies.     

Serum interleukin-6 levels in metastatic renal cell carcinoma before treatment with interleukin-2 correlates with paraneoplastic syndromes but not patient survival

PURPOSE: We sought to determine the frequency of interleukin-6 (IL-6) expression in renal cancer cell lines, the frequency of the detection of IL-6 in the serum of patients with metastatic renal cell carcinoma, whether serum IL-6 level correlates with the development of paraneoplastic syndromes and whether serum IL-6 level in patients with metastatic renal cancer correlates with response to treatment with interleukin-2 (IL-2) or patient survival. MATERIALS AND METHODS: Conditioned media from 21 cell lines from 20 patients were examined for IL-6. We identified 2 matched groups of patients with metastatic renal cancer (30 responders and 29 nonresponders) to IL-2 based immunotherapy. Stored pretreatment serum specimens were evaluated for IL-6. Medical records were reviewed to determine the presence of paraneoplastic syndromes. RESULTS: IL-6 was detected in 19 of 21 renal cancer cell lines (90%) obtained from 20 patients with metastatic renal cancer as well as in the serum of 33 of 59 patients (56%) with metastatic renal cell carcinoma. A significant association between serum IL-6 level and anemia (p = 0.0032), elevated platelet count (p = 0.01), decreased albumin (p = 0.034) and elevated alkaline phosphatase (p = 0.04) was found. A trend was noted of the association of increased serum IL-6 level and fever (p = 0.051). No correlation was found between pretreatment serum IL-6 level and survival or response to IL-2. CONCLUSIONS: IL-6 was frequently secreted by renal cancer cell lines but it was only present in the serum of approximately half of the patients with metastatic renal cancer. Elevations of serum IL-6 were associated with paraneoplastic manifestations frequently seen in patients with renal cancer, including anemia, thrombocytosis, decreased albumin and elevations of alkaline phosphatase (Stauffer's syndrome). A weak relationship was noted between serum IL-6 level and fever but none was noted between that and survival or response to IL-2.