CRMP5 antibodies in patients with small-cell lung cancer or thymoma

The collapsin response mediator protein 5 (CRMP5) antibody is usually associated with paraneoplastic neurological syndrome (PNS) and small-cell lung cancer (SCLC) or thymoma. The objective of this study was to assess the frequency of CRMP5 antibodies in patients with such tumours and to see if the presence of antibodies was associated with prognosis in these cancers. A multi-well adapted immunoprecipitation assay using radiolabelled recombinant CRMP5 protein, produced by coupled in vitro transcription/translation, was used for the detection of CRMP5 antibodies. Sera from 200 patients with SCLC, 73 patients with thymoma and myasthenia gravis (MG) and from 300 healthy blood donors were examined for CRMP5 antibodies. Positive sera were also examined by immunofluorescence and immune blots. The serological results were compared with disease severity of the patients with thymoma or SCLC. CRMP5 antibodies were detected in 10/200 (5%) of the SCLC, 9/73 (12%) of the thymomas and in 2/300 (0.6%) of the healthy controls by immunoprecipitation. The antibodies were less frequently detected by immunofluorescence or immune blots. There was no significant correlation between CRMP5 antibodies and disease severity. CRMP5 antibodies are more than twice as frequent, and the antibody levels are higher in patients with thymoma and MG than in patients with SCLC. The antibodies are correlated to these tumours, but not to disease severity.

[Limbic encephalitis--a diagnostic challenge]

BACKGROUND

The etiology of limbic encephalitis (LE) is often autoimmune. Autoimmune LE is often paraneoplastic and should be suspected in patients with subacute confusional states. Subgroups of LE require different treatment, and the prognosis is variable; making the correct diagnosis is therefore essential for a good outcome.

MATERIAL AND METHODS

The article is based on the authors' clinical experience with these patients and a review of recent literature retrieved from PubMed with the key words limbic encephalitis, limbic inflammation, paraneoplastic encephalitis, limbic and cancer, ion channel antibodies and viral encephalitis. Two case reports illustrate important clinical points.

RESULTS AND INTERPRETATION

Patients with LE constitute a heterogenous group with neuropsychiatric features, seizures and amnesia as the main symptoms. An early diagnosis is essential to limit sequelae. Viral encephalitis and Wernicke-Korsakoff Syndrome are important differential diagnoses. Presence of an onconeural antibody in serum is a specific tumour marker that should be used for screening all patients for malignancy. Not all cases of LE are paraneoplastic; ion channel antibodies can be an important marker for good response to immunosuppressive therapy in this group.

Long-term mortality among young ischemic stroke patients in western Norway

OBJECTIVES

To obtain data on long-term mortality among young ischemic stroke patients compared with controls in this population-based study.

MATERIAL AND METHODS

We used Kaplan-Meier survival analysis to compare 232 patients aged 15-49 years with first-ever cerebral infarction in 1988-1997 and 453 controls followed from inclusion to death or 1 August 2005 for 2515 and 5558 person-years respectively. In a subanalysis of 192 patients, we compared risk factor variables using the Kaplan-Meier method and log-rank testing. We applied a Cox proportional hazards model to adjust for multiple risk factors.

RESULTS

Forty-five patients and nine controls died during follow-up (P < 0.0005). Independent risk factors for mortality were active tumor disease (P < 0.0005), high consumption of alcohol (P < 0.0005), coronary atherosclerosis (P < 0.001), living alone (P < 0.02), seizures (P < 0.04) and smoking (P = 0.08).

CONCLUSIONS

Long-term mortality was significantly increased among young stroke patients, mainly due to such lifestyle factors as high consumption of alcohol and tobacco.

Paraneoplastic neurological syndromes and onconeural antibodies: clinical and immunological aspects

Paraneoplastic neurological syndromes (PNS) are infrequent disorders that are associated with cancer. The syndromes are highly heterogeneous and often affect several areas of the nervous system. Among the most well-known syndromes are paraneoplastic encephalomyelitis, cerebellar degeneration, sensory neuronopathy, and Lambert-Eaton myastenic syndrome. There are various associated tumors, in particular small cell lung cancer, cancer of the breast and ovary, and thymoma. The onset of neurological symptoms often precedes the cancer diagnosis, and the recognition of a paraneoplastic syndrome should lead to immediate search for cancer. The etiology of the paraneoplastic syndromes is believed to be autoimmune. Antibodies to onconeural antigens, expressed in the tumor of the affected individual and in normal neurons, are found in many of the patients. These antibodies are useful markers for paraneoplastic etiology. The pathogenesis of the PNS is uncertain, but cellular immune responses are thought to be the main effector mechanism. The cornerstone of therapy is the identification and treatment of the underlying malignancy. In some of the disorders, immunosuppressive therapy is of additional benefit. The prognosis of the different PNS varies depending on the level of affection and the degree of neuronal death.

Pretreatment of Mass Spectral Profiles: Application to Proteomic Data

Mass spectral profiles are influenced by several factors that have no relation to compositional differences between samples: baseline effects, shifts in mass-to-charge ratio (m/z) (synchronization/alignment problem), structured noise (heteroscedasticity), and, differences in signal intensities (normalization problem). Different procedures for pretreatment of whole mass spectral profiles described by almost 50,000 m/z values are investigated in order to find optimal approaches with respect to revealing the information content in the data. In order to quantitatively assess the impact of different procedures for pretreatment of mass spectral profiles, we use factorial designs with the ratio between intergroup and intragroup (replicate) variance as response. We have examined the influence of smoothing, binning, alignment/synchronization, noise pattern, and normalization on data interpretation. Our analysis shows that the spectral profiles have to be corrected for heteroscedastic noise prior to normalization. An nth root transform, where n is a small, positive integer, is used to create a homoscedastic noise structure without destroying the linear correlation structures describing individual components when using whole mass spectral profiles. The choice of n is decided by a simple graphic procedure using replicate information. Log transform is shown to change the heteroscedastic noise structure from being dominant in high-intensity regions, to produce the largest noise in the low-intensity regions. In addition, log transform has a negative effect on the collinearity in the profiles. Factorial designs reveal strong interactions between several of the pretreatment steps, e.g., noise structure and normalization. This underlines the limited usability of looking at the different pretreatment steps in isolation. Binning turns out to be able to substitute smoothing of spectra by, for example, moving average or Savitsky-Golay, while, at the same time, reducing the data point description of the profiles by 1 order of magnitude. Thus, if the sampling density is high, binning seems to be an attractive option for data reduction without the risk of losing information accompanying the integration of profiles into peaks. In the absence of smoothing, binning should be executed prior to alignment. If binning is not performed, the order of pretreatment should be smoothing, alignment, nth root transform, and normalization.

Arterial Events after Ischemic Stroke at a Young Age: A Cross-Sectional Long-Term Follow-Up of Patients and Controls in Western Norway

BACKGROUND

There is little information in the literature on the risk of vascular events among patients after ischemic stroke at a young age.

METHODS

We examined 144 (77%) of 187 long-term survivors of ischemic stroke and compared them with 167 controls. Mean age of the 187 survivors at inclusion was 41.0 years and mean age of the participating patients was 40.8 years.

RESULTS

After a mean duration of observation of 11.8 years, we registered arterial events among 54 patients and 14 controls. Ninety patients with index stroke only had no significant risk factors compared with controls without arterial events. Compared with 54 patients with several arterial events, age, incidence of diabetes mellitus, smoking and family history of coronary disease were significantly lower.

CONCLUSIONS

The results from index-stroke-only patients suggest that a subgroup of patients has a benign course, probably without chronic vascular disease.

Fc? Receptor Polymorphisms are not Associated with Autoimmune Addison's Disease

Polymorphisms in the low-affinity Fcgamma receptors (FcgammaR) modulate their capacity to bind IgG and the subsequent immune response. Different FcgammaR polymorphisms have been reported to be associated with susceptibility and severity of various autoimmune diseases. We wanted to investigate associations between FcgammaR polymorphisms and autoimmune primary adrenal failure (Addison's disease). We have genotyped 149 patients with Addison's disease and 89 healthy controls for common polymorphisms in the genes coding for FcgammaRIIa, FcgammaRIIIa and FcgammaRIIIb using polymerase chain reaction. Patients with Addison's disease and controls showed no differences in genotype distributions of FcgammaRIIa, FcgammaRIIIa and FcgammaRIIIb. The results indicate that different FcgammaR polymorphisms do not have an impact on immune responses involved in the development of autoimmune Addison's disease.

Antibodies to CRMP3-4 associated with limbic encephalitis and thymoma

We present a case with subacute limbic encephalitis (LE) and thymoma. Neither classical onconeural antibodies nor antibodies to voltage gated potassium channels (VGKC) were detected, but the serum was positive for anti-glutamic acid decarboxylase (GAD). The patient serum also stained synaptic boutons of pyramidal cells and nuclei of granule cells of rat hippocampus. The objective of the study was to identify new antibodies associated with LE. Screening a cDNA expression library identified collapsin response mediator protein 3 (CRMP3), a protein involved in neurite outgrowth. The serum also reacted with both CRMP3 and CRMP4 by Western blot. Similar binding pattern of hippocampal granule cells was obtained with the patient serum and rabbit anti-serum against CRMP1-4. The CRMP1-4 antibodies stained neuronal nuclei of a biopsy from the patient's temporal lobe, but CRMP1-4 expression in thymoma could only be detected by immunoblotting. Absorption studies with recombinant GAD failed to abolish the staining of the hippocampal granule cells. Our findings illustrate that CRMP3-4 antibodies can be associated with LE and thymoma. This has previously been associated with CRMP5.

Ri antibodies in patients with breast, ovarian or small cell lung cancer determined by a sensitive immunoprecipitation technique

The presence of circulating antineuronal antibodies has been associated with paraneoplastic neurological syndromes (PNS). Ri antibodies are often associated with lung or breast cancer, but the prevalence of such antibodies in large cancer materials is largely unknown. We used a highly sensitive immunoprecipitation assay to study the level of Ri antibodies in blood samples from 200 patients with small cell lung cancer (SCLC), 253 patients with breast cancer and 557 patients with ovarian cancer. Two hundred blood donors and six Ri positive PNS patients served as controls. The recombinant antigen used in the immunoprecipitation assay was radiolabeled by a coupled in vitro transcription and translation (ITT) technique, enabling low levels of antibodies to be detected. None of the blood donors contained Ri antibodies, whereas all of the sera from the PNS patients were positive. Ri antibodies were present in 4.5% of the patients with SCLC, 0.8% of the patients with breast cancer and in 0.2% of the patients with ovarian cancer. Retesting of the Ri positive samples with immunofluorescense and immune blot showed that the immunoprecipitation technique was more sensitive than the other immune assays. Ri antibodies were not associated with PNS in the patients with breast or ovarian cancer. Neurological data were not available for the SCLC patients, but in these, Ri antibodies were not associated with survival.

Detection of Autoantibodies to the BTB-kelch Protein KLHL7 in Cancer Sera

The aim of the study was to search for novel targets of autoantibodies in patients with paraneoplastic neurological syndromes (PNS). PNS are mediated by immune reactions against autoantigen(s) shared by the cancer cells and the nervous system. By serological screening of a rat cerebellum cDNA expression library using anti-Hu-positive sera from three patients with paraneoplastic encephalomyelitis (PEM), we identified an open reading frame encoding an isoform of the BTB-kelch protein KLHL7. Immunohistochemical studies demonstrated that the KLHL7 protein is expressed in the nuclei of neurones, but not in other tissues including various cancers. However, the KLHL7 protein was detected in the nuclei of cancer cell lines. Antibodies to KLHL7 were detected by an immunoprecipitation assay in sera from 12 of 254 (4.7%) patients with various cancers and 2 of 170 blood donors (1.2%). None of 50 sera from patients with multiple sclerosis were positive for KLHL7 antibodies. Sixteen patients with classical PNS and anti-Hu or anti-Yo antibodies were also negative for KLHL7 antibodies. Seven cancer patients with KLHL7 antibodies had various signs of neurological disease that could be related to cancer, whereas the remaining five seropositive cancer patients had no clinical signs of possible PNS. The present results indicate that KLHL7 antibodies are associated with various cancers, and in some patients also with neurological disease. Whether KLHL7 antibodies can be used as paraneoplastic markers for PNS remains to be determined.

Management of paraneoplastic neurological syndromes: report of an EFNS Task Force

Paraneoplastic neurological syndromes (PNS) are remote effects of cancer on the nervous system. An overview of the management of classical PNS, i.e. paraneoplastic limbic encephalitis, subacute sensory neuronopathy, paraneoplastic cerebellar degeneration, paraneoplastic opsoclonus-myoclonus, Lambert-Eaton myasthenic syndrome and paraneoplastic peripheral nerve hyperexcitability is given. Myasthenia gravis and paraproteinemic neuropathies are not included in this report. No evidence-based recommendations were possible, but good practice points were agreed by consensus. Urgent investigation is indicated, especially in central nervous system (CNS) syndromes, to allow tumour therapy to be started early and prevent progressive neuronal death and irreversible disability. Onconeural antibodies are of great importance in the investigation of PNS and can be used to focus tumour search. PDG-PET is useful if the initial radiological tumour screen is negative. Early detection and treatment of the tumour is the approach that seems to offer the greatest chance for PNS stabilization. Immune therapy usually has no or modest effect on the CNS syndromes, whereas such therapy is beneficial for PNS affecting the neuromuscular junction. Symptomatic therapy should be offered to all patients with PNS.

Yo antibodies in ovarian and breast cancer patients detected by a sensitive immunoprecipitation technique

Onconeural antibodies are found in patients with cancer and are associated with paraneoplastic neurological syndromes (PNS). The objective of the present study was to assess the frequency of Yo antibodies in ovarian and breast cancer using a sensitive immunoprecipitation technique, and to look for any association of Yo antibodies with neurological symptoms and prognostic factors. A multiwell adapted fluid-phase immunoassay using radiolabelled recombinant cerebellar degeneration related protein (cdr2), produced by coupled in vitro transcription/translation was used for the detection of Yo antibodies. This technique combines high specificity and sensitivity with high sample analysing capacity for the antibody in question. Sera or EDTA-blood from 810 ovarian (n = 557) and breast cancer (n = 253) patients were analysed for Yo antibodies by immunoprecipitation, as well as immunofluorescence and immune blots. Two hundred healthy blood donors and sera from 17 patients with paraneoplastic cerebellar degeneration and Yo antibodies served as controls. Immunoprecipitation was more sensitive in detecting Yo antibodies than immunofluorescence and immune blots. The prevalence of Yo antibodies was 13/557 (2.3%) in ovarian cancer and 4/253 (1.6%) in breast cancer using immunoprecipitation. Yo antibodies were not correlated with specific histological subgroups. The Yo index of ovarian cancer patients in FIGO stage IV was higher compared to FIGO stage I-III. The prevalence of Yo antibodies was 3 times higher in patients with stage III breast cancer than in stage I and II. Only 2/17 (11.8%) patients with Yo antibodies detected during the screen of 810 cancer patients had PNS. The results show that the prevalence of Yo antibodies is low in ovarian and breast cancer. Yo antibodies may be associated with advanced cancer, but less often with PNS.

FcgammaR and multiple sclerosis: an overview

Receptors for the Fc domain of IgG (FcgammaR) play a key role in the immune system by linking the cellular and humoral immune systems. Despite extensive documentation of CNS-specific antibodies in cerebrospinal fluid and plaques in multiple sclerosis (MS) patients, the role of FcgammaR in this disease remains largely unexplored. Studies indicate however, that polymorphisms in some FcgammaR genes and treatment that induces FcgammaR on immune-competent cells could influence disease progression and treatment response.

An immunoprecipitation assay for the detection of onconeural antibodies

INTRODUCTION

Onconeural antibodies are found in some patients with cancer, and are associated with paraneoplastic neurological syndromes.

METHOD

A multi-well adapted fluid-phase immunoassay using radiolabelled recombinant onconeural proteins for the detection of onconeural antibodies is described.

RESULT AND CONCLUSION

This immunoprecipitation technique is more sensitive in detecting onconeural antibodies than immunohistochemistry and immune blots.

Autopsy findings in the nervous system and ovarian tumour of two patients with paraneoplastic cerebellar degeneration

OBJECTIVES

To review autopsy findings in paraneoplastic cerebellar degeneration.

MATERIALS AND METHODS

We report the autopsy results of two individuals with paraneoplastic cerebellar degeneration and ovarian cancer.

RESULTS

Both patients had extensive loss of cerebellar Purkinje cells and general activation of microglia in the central nervous system, as well as signs of immunactivation in the medulla.

CONCLUSION

The immunoactivation in PCD is widespread and involving more than the cerebellum.

cDNA expression library screening for identification of novel onconeural antigens

Paraneoplastic neurological disorders occur as a remote effect of cancer. Tumor cells expressing neuron-specific proteins elicit an autoimmune response, resulting in the production of various antibodies. The antibodies are usually associated with different syndromes, but the identity of many of the antigens is still unknown. Screening a cDNA expression library is a powerful technique that allows identification of previously uncharacterized antigens. By using patient sera containing antibodies, the antigens of interest can be isolated and further characterized.

High dose methylprednisolone induces FcγRI on granulocytes in MS-patients

Immune complexes impinge on receptors for the Fc domain of IgG (FcgammaR) and may thus influence the disease course in multiple sclerosis (MS). We analyzed FcgammaR distribution on monocytes and granulocytes in twenty relapsing-remitting MS patients at baseline, immediately after a five day course of high dose intravenous methylprednisolone (IVMP) treatment and after two months. After a five day course of IVMP the proportion of granulocytes with FcgammaRI was increased, P=0,002. There was no change in FcgammaRII and FcgammaRIII expression. The effect of IVMP on FcgammaRI expression could be important for the clearance of immune complexes in MS.

Proteasome antibodies in paraneoplastic cerebellar degeneration

Antibodies to proteasome have been detected in several autoimmune diseases, including multiple sclerosis. We have investigated the presence of such antibodies in patients with paraneoplastic neurological syndromes, by Western blotting and immunohistochemistry. Antibodies to 20S proteasome were detected in the majority of patients with paraneoplastic cerebellar degeneration (PCD), but in only one of nine sera from patients with paraneoplastic encephalomyelitis/sensory neuronopathy (PEM/SN), and were not found in cancer patients in general. The results suggest that the immune responses in PCD differ from those of PEM/SN, whereas the functional significance of proteasome antibodies in PCD is yet to be determined.

Ethnic variation of Fc gamma receptor polymorphism in Sami and Norwegian populations

Receptors for the Fc domain of IgG (Fc gammaR) play a critical role in linking cellular and humoral immunity. The various Fc gammaR genotypes may contribute to differences in infectious and immune-related diseases in various ethnic populations. The Samis are the aboriginal inhabitants of Norway and Fennoscandinavia and differ ethnically from the Norwegians. The distribution of various immune-related diseases has been reported to differ between Sami and Norwegians. This is the first study to evaluate the distribution of Fc gammaR polymorphisms in a Sami population. Two hundred Samis were genotyped for polymorphisms in the Fc gammaRIIA, Fc gammaRIIIA and Fc gammaRIIIB genes. The genotype and allele frequencies were compared with those of 272 healthy Norwegians. The Sami and Norwegian Fc gammaRIIA, Fc gammaRIIIA and Fc gammaRIIIB genotypes differed significantly. The Samis had higher frequencies of the Fc gammaRIIa-H/H131, Fc gammaRIIIa-F/F158 and Fc gammaRIIIb-NA1/NA1 genotypes. The Fc gammaR genotypes were non-randomly distributed in both populations. These findings may be important for the prevalence of autoimmune and infectious diseases in the two populations.

Severity of Guillain-Barré syndrome is associated with Fc gamma Receptor III polymorphisms

Macrophages and ganglioside-specific IgG are involved in the pathogenesis of Guillain-Barre syndrome (GBS). Leukocyte IgG receptors (Fc gammaR) confer potent cellular effector functions to the specificity of IgG. The efficacy of IgG-mediated cellular inflammatory responses is determined by functional polymorphisms of three Fc gammaR subclasses (Fc gammaRIIa: H131/R131; Fc gammaRIIIa: V158/F158; Fc gammaRIIIb: NA1/NA2). Fc gammaR genotype distributions were determined in a Dutch, and British cohort of GBS patients and controls. In addition, a meta-analysis incorporating all previously published data, encompassing a total of 345 GBS patients and 714 healthy controls, was performed. Results suggest that Fc gammaRIII genotypes may represent mild disease-modifying factors in GBS.

Ethnic Variations of IL-10 Polymorphisms in a Sami and Norwegian Population

Interleukin-10 (IL-10) production is genetically determined and influenced by different polymorphisms in the promoter region of IL-10. These polymorphisms may contribute to the risk and clinical outcome of various infectious and immunological-related diseases. The Samis are the aboriginal inhabitants of Norway and Fennoscandinavia and are ethnically different from the Norwegians. Different distribution of various immune-related diseases among the Samis compared with Norwegians have been reported. This is the first study to evaluate the distribution of IL-10 polymorphisms in the Sami population. Two hundred healthy Samis were genotyped for polymorphisms in the promoter region of IL-10 at region -1082 (G/A), -819 (T/C) and -592 (A/C). The allele frequencies, genotypes and haplotypes were compared with 187 healthy Norwegians. A significantly higher number of the Samis than the Norwegians had the ATA/ATA genotype, whereas the Norwegians displayed a higher frequency of the GCC/GCC genotype (P=0.0057). There was a significant difference in haplotypes in the two populations with a P=0.0024. These findings may be important for the distribution and clinical outcome of various infectious and immune-related disorders in the two populations.

IL-6: an early marker for outcome in acute ischemic stroke

OBJECTIVES

Inflammation plays an important role in the pathophysiology of stroke. We correlated interleukin (IL)-6, IL-10, C-reactive protein (CRP) and T-lymphocyte subtype levels in acute ischemic stroke patients with stroke volume and clinical outcome.

MATERIALS AND METHODS

Blood samples were obtained from 11 patients at defined intervals during 1 year. Nine healthy age-matched subjects served as controls. IL-6, IL-10 and CRP were quantified by enzyme-linked immunosorbent assay and T lymphocytes by flow cytometry. Volume measurement was carried out by computed tomography or magnetic resonance imaging and clinical outcome was scored by the European stroke scale (ESS) and Barthel index (BI).

RESULTS

IL-6 levels were increased in the acute phase of stroke compared with healthy controls (P = 0.002) and correlated with larger stroke volume (P = 0.012) and less favorable prognosis after 1 year, measured by ESS (P = 0.014) and BI (P = 0.006). IL-10, CRP and T-lymphocyte subtypes in the acute phase were not correlated with stroke volume or clinical outcome.

CONCLUSION

IL-6 seems to be a robust early marker for outcome in acute ischemic stroke.

[Miller-Fisher syndrome]

BACKGROUND

Miller-Fisher syndrome is characterised by the clinical triad of ophthalmoplegia, ataxia and areflexia and is considered a variant form of Guillain-Barré syndrome. In western countries the incidence is reported to be approximately 1-5% that of Guillain-Barré syndrome. Approximately 90% of patients have antibodies against the ganglioside GQ1b, which is of diagnostic and pathogenic importance.

MATERIAL AND METHODS

We present two patients with Miller-Fisher syndrome and describe clinical features and possible mechanisms of GQ1b antibodies.

RESULTS AND INTERPRETATION

Both patients presented with the classical triad of symptoms and GQ1b antibodies after upper respiratory tract infections. One of the patients had a more severe form with additional bulbar signs and was treated with plasma exchange. Both made almost complete recoveries within a few months.

IL-10 promoter haplotype influence on interferon treatment response in multiple sclerosis

The level of interleukin-10 (IL-10) expression is related to polymorphisms -1082 (G/A), -819 (T/C) and -592 (A/C) in the promoter region of the IL-10 gene, which constitute three haplotypes, GCC, ATA, and ACC. The ATA (a non-GCC) haplotype, which is associated with low IL-10 expression, has been shown to improve interferon (IFN) treatment response in hepatitis C. We analysed the distribution of IL-10 promoter haplotype combinations to determine whether they could influence initial IFN treatment response in 63 patients with relapsing-remitting multiple sclerosis (MS). The patients were grouped into non-GCC or GCC haplotypes, and the clinical and magnetic resonance imaging (MRI) disease activity was compared in the two groups. During the first 6 months of treatment, MS patients with non-GCC haplotypes experienced fewer new MRI T1-contrast enhancing lesions [0.77+/-0.36 (SEM)] than patients with the GCC haplotype (2.45+/-0.57) (P=0.05, Mann-Whitney U test). No differences were detected on clinical disease activity. The results suggest an influence of IL-10 promoter polymorphisms on IFN treatment response in MS.

Fcgamma receptor IIIA polymorphism as a risk-factor for coronary artery disease

BACKGROUND

Inflammation is important in the pathogenesis of atherosclerosis. Polymorphisms of Fc receptors for IgG (FcgammaR) are associated with modifying effects of several infectious and autoimmune diseases. We have assessed the relationship between polymorphisms in three different FcgammaR genes and coronary artery disease (CAD).

METHODS AND RESULTS

We genotyped for the FcgammaRIIA-R/H131, the FcgammaRIIIB-Na1/Na2, and the FcgammaRIIIA-F/V158 polymorphisms in 882 patients undergoing diagnostic coronary angiography. Significant CAD was defined as >/=50% lumen diameter stenosis in at least one coronary artery. In the analysis, no association was found between the FcgammaRIIA and FcgammaRIIIB genotypes and CAD, whereas the FcgammaRIIIA genotype was strongly related. Compared to those being heterozygous, or homozygous for the F allele, patients homozygous for the V allele had significantly reduced risk: OR, 0.53; (CI, 0.32-0.90). Additional adjustment for classical risk factors and sedimentation rate did not affect the results. The V/V genotype was also inversely related to the extent of CAD defined as no CAD, single, double or triple vessel disease (P trend=0.002).

CONCLUSIONS

Our data provide evidence for an association between FcgammaRIIIA allelic variants and coronary atherosclerosis. Genetic variation in this IgG-receptor may influence the clearance of antibodies by monocyte-derived macrophages involved in the pathogenesis of CAD.

Pyridoxal phosphatase is a novel cancer autoantigen in the central nervous system

Autoantibodies against many proteins are common in sera from patients with various types of cancer. These antibodies are sometimes involved in the development of conditions associated with cancer, such as paraneoplastic neurologic disorders. We used a human brain cDNA expression library and serum from a paraneoplastic neurologic disorder patient to search for new autoantigens in the nervous system. Pyridoxal phosphatase was identified as a novel autoantigen. Expression studies showed that pyridoxal phosphatase was strongly expressed in various parts of the central nervous system. Sera contained antibodies against pyridoxal phosphatase in 22 of 243 (9.1%) patients with lung cancer and eight of 113 (7.1%) with other forms of cancer vs two of 88 (2.3%) healthy control subjects. In addition, 2-4% of patients with different autoimmune diseases had autoantibodies against pyridoxal phosphatase. None of the antipyridoxal phosphatase-positive patients were known to have a paraneoplastic neurologic disorder. Hence, autoantibodies against pyridoxal phosphatase correlate with cancer but not necessarily with the subset of patients with paraneoplastic neurological disorders although serum from such a patient was used to screen the cDNA library. This study showed that yet another enzyme involved in pyridoxal 5'-phosphate metabolism is an autoantigen. Thus, pyridoxal 5'-phosphate seems to be a common denominator for autoantigens involved in autoimmune diseases.

Paraneoplastic antibodies detected by isoelectric focusing of cerebrospinal fluid and serum

Patients with paraneoplastic neurological syndromes often produce intrathecal antibodies. We have employed isoelectric focusing and peroxidase-labeled anti-IgG or 35S-labeled Hu or Yo antigens to identify oligoclonal bands (OCB) representing either total IgG or Hu or Yo antibodies in serum and CSF of patients with paraneoplastic encephalomyelitis (PEM) or paraneoplastic cerebellar degeneration (PCD). OCBs representing paraneoplastic antibodies were found in all CSF, but in only three sera. Yo antibodies represented the majority of IgG bands in PCD-CSF, which may reflect a limited immune response, whereas in PEM/SN, there were numerous additonal IgG bands of unknown specificity, indicating a broader immune response in these patients.

Systemic complement activation following human acute ischaemic stroke

The brain tissue damage after stroke is mediated partly by inflammation induced by ischaemia-reperfusion injury where the complement system plays a pivotal role. In the present study we investigated systemic complement activation and its relation to C-reactive protein (CRP), a known complement activator, and other inflammatory mediators after acute ischaemic stroke. Sequential plasma samples from 11 acute stroke patients were obtained from the time of admittance to hospital and for a follow-up period of 12 months. Nine healthy gender- and age-matched subjects served as controls. The terminal SC5b-9 complement complex (TCC), CRP, soluble adhesion molecules (L-, E- and P- selectin, ICAM, VCAM) and cytokines [tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-8] were analysed. All parameters were within normal values and similar to the controls the first hours after stroke. Terminal complement complex (TCC) increased significantly from 0.54 to 0.74 AU/ml at 72 h (P = 0.032), reached maximum at 7 days (0.90 AU/ml, P < 0.001), was still significantly increased at 12 days (0.70 AU/ml, P = 0.009) and thereafter normalized. CRP increased significantly from 1.02 to 2.11 mg/l at 24 h (P = 0.023), remained significantly increased for 1 week (2.53-2.94 mg/l, P = 0.012-0.017) and thereafter normalized. TCC and C-reactive protein (CRP) correlated significantly (r = 0.36, P < 0.001). The increase in TCC and CRP correlated to the size of infarction (r = 0.80 and P = 0.017 for TCC; r = 0.72 and P = 0.043 for CRP). No significant changes were seen for adhesion molecules and cytokines. In conclusion, transitory systemic complement activation takes place after stroke. The early rise in CRP and the following TCC increase suggest a possible role for CRP in complement activation, which may contribute to inflammation after stroke.

Paraneoplastic antibodies against HuD detected by a sensitive radiobinding assay

Patients with paraneoplastic encephalomyelitis(subacute sensory neuronopathy) (PEM/SSN), most commonly associated with small-cell lung cancer (SCLC), frequently harbor Hu antibodies, which are usually detected by indirect immunohistochemistry or immunoblot. We developed a new radioimmunobinding assay to detect Hu antibodies based on in vitro transcribed and translated (ITT) HuD. High levels of Hu antibodies were detected in all seven PEM/SSN patients tested, but not in any of 15 patients with other paraneoplastic syndromes, 20 patients with Sjögren's syndrome, 20 patients with miscellaneous tumors and 99 of 100 blood donors. One of the blood donors had low levels of Hu antibodies. The radiobinding assay detected Hu antibodies in 45 of 191 (24%) patients with SCLC, in comparison with immunofluorescence and immuno dot blot, where only 34 of 191 (18%) were detected. All patients with Hu antibodies detected by immunofluorescence and immuno dot-blot were also positive by the radioimmunobinding assay. The results demonstrate that this assay is very specific and sensitive for the detection of Hu antibodies.

Hu and voltage-gated calcium channel (VGCC) antibodies related to the prognosis of small-cell lung cancer

PURPOSE

Hu antibodies previously have been associated with longer survival of patients with small-cell lung cancer (SCLC). Voltage-gated calcium channel (VGCC) antibodies play a pathogenic role in Lambert Eaton myasthenic syndrome, which is also associated with SCLC. These antibodies may reduce tumor growth in patients with the neurologic disease, but it is not clear whether they provide prognostic information in those without neurologic symptoms.

PATIENTS AND METHODS

Two hundred patients with SCLC (age 39 to 79 years; mean, 62.3 years; 129 males and 71 females) receiving chemotherapy were studied for the presence of Hu and VGCC antibodies. Sera were examined for Hu antibodies by an in vitro transcription-translation-based immunoprecipitation technique and by immunohistochemistry/dot blot. VGCC (P/Q subtype) antibodies were detected by radioimmunoassay. Survival analysis was used to analyze the data. Results Hu antibodies were detected in 51 of 200 patients (25.5%) by in vitro transcription-translation-based immunoprecipitation and in 37 of 200 patients (18.5%) by immunohistochemistry or dot blot, whereas VGCC antibodies were detected in only 10 of 200 patients (5%). The presence of Hu antibodies did not correlate with VGCC antibodies, and there was no association between Hu or VGCC antibodies and the extent of disease or survival.

CONCLUSION

Hu and VGCC antibodies are found in a proportion of SCLC patients, irrespective of neurologic symptoms, but their presence does not correlate with the prognosis of the SCLC.

Intracortical multiple sclerosis lesions are not associated with increased lymphocyte infiltration

The present study examined the extent and distribution of lymphocyte infiltration in demyelinated lesions in the cerebral cortex of multiple sclerosis (MS) patients. Tissue sections from the brain of 10 MS patients and five patients without neurological disease were double labeled for myelin basic protein and the lymphocyte markers CD3, CD4, CD8, CD45RO, and CD20. The highest density of CD3-positive T cells was found in MS white matter lesions (40.4/10 high power fields (hpf)). Fewer T cells were detected in cortical lesions that extended through both white and gray matter (12.1/10 hpf; P < 0.001). The lowest number of T cells was detected in intracortical demyelinated lesions (1.1/10 hpf). This was equal to the lymphocyte density in nondemyelinated cerebral cortex within the same tissue block (1.1/10 hpf) or cerebral cortex in control brains (1.8/10 hpf). A similar distribution was found using the CD4, CD8, and CD45RO markers. CD20-positive B cells were scarce in all specimens examined. These data indicate that areas of intracortical demyelination in chronic MS are not associated with an increased number of lymphocytes, or an altered distribution of lymphocyte subsets, when compared with control areas in MS and control patients. This finding indicates that the extent of lymphocyte infiltration in MS lesions is dependent on lesion location.

Subpial demyelination in the cerebral cortex of multiple sclerosis patients

The extent and pattern of demyelination in the cerebral cortex was determined in 78 tissue blocks from the brains of 20 multiple sclerosis (MS) patients and 28 tissue blocks from 7 patients without neurological disease. Tissue blocks from 4 predetermined areas (cingulate gyrus, frontal, parietal, and temporal lobe) were studied, irrespective of macroscopically evident MS plaques. All tissue blocks contained cerebral cortex and periventricular and/or subcortical white matter. One hundred and nine demyelinating lesions were detected in the cerebral cortex, of which 92 (84.4%) were purely intracortical and 17 (15.6%) were lesions extending through both white and gray matter areas. In 5 of the 20 MS brains, subpial demyelination was extensive in the 4 widely spaced cortical areas studied, thus considered to represent a general cortical subpial demyelination. The percentage of demyelinated area was significantly higher in the cerebral cortex (mean 26.5%, median 14.1%) than in white matter (mean 6.5%, median 0%) (p = 0.001). Both gray and white matter demyelination was more prominent in the cingulate gyrus than in the other areas examined (p < 0.05). These results indicate that the cerebral cortex is likely to be a predilection site for MS lesions and identify general cortical subpial demyelination as a distinct pattern occurring in a significant subpopulation of MS patients.

GM1 antibodies in post-polio syndrome and previous paralytic polio

We studied the relationship between post-polio syndrome (PPS) and GM1 antibodies, since such antibodies have been associated with PPS and motor neuron disorders. Sera from 144 patients with previous poliomyelitis (105 paralytic, 22 nonparalytic and 17 PPS), 60 with previous Guillain-Barré syndrome, 44 with amyotrophic lateral sclerosis (ALS) and 22 healthy blood donors were analyzed with ELISA for GM1 IgM, IgG and IgA antibodies. GM1 antibodies were present in 14% of the PPS patients, but the prevalence did not differ significantly from that of the other groups. Our study does not support the hypothesis that GM1 antibodies are involved in the pathogenesis of PPS.

Interleukin-10 promoter polymorphisms in patients with Guillain-Barré syndrome

Interleukin-10 (IL-10) may have both pro- and anti-inflammatory effects in Guillain-Barré syndrome (GBS). The distribution of polymorphisms in the IL-10 gene (-1082 (G/A), -819 (T/C) and -592 (A/C)) was analysed to determine whether they could influence disease susceptibility or clinical course in GBS. The -592 CC and -819 CC genotypes associated with increased IL-10 response were more frequent in the GBS patients than in the controls (P=0.027), but the polymorphisms did not influence the clinical course of the disease.

Immunoglobulin KM genes in Guillain-Barré syndrome

Guillain-Barré syndrome is associated with antecedent Campylobacter jejuni infection. Only a minority of the infected individuals, however, develops the disease, implying a role for genetic factors in conferring susceptibility. To determine the role of immunoglobulin KM genes (genetic markers of the constant region of kappa chains) in the etiology of this syndrome, we genotyped 83 patients and 196 healthy controls from Norway for KM1 and KM3 alleles by polymerase chain reaction-restriction fragment length polymorphism. The frequency of KM3 homozygotes was significantly increased in patients compared with controls (86.7% vs. 74%, P=0.01, odds ratio=2.3). Conversely, the frequency of KM1/KM3 heterozygotes was significantly decreased in patients compared with controls (13.3% vs. 26%, P=0.01, odds ratio=0.4). These results suggest that KM genes may be relevant to the etiology of Guillain-Barré syndrome.

Fcgamma receptor IIIA polymorphism as a risk factor for acute poliomyelitis

Poliomyelitis is a viral infection that causes flaccid paralysis in approximately 1% of cases. The Fc receptors for immunoglobulin G (FcgammaR) are associated with modifying effects of several infectious and autoimmune diseases. To assess the influence of FcgammaR polymorphisms on the acute and late course of poliomyelitis, 110 Norwegian patients with well-defined histories of acute poliomyelitis were genotyped, of whom 50 suffered from the postpolio syndrome (PPS). In comparison with healthy control subjects without a history of poliomyelitis, significantly fewer patients had the FcgammaRIIIA genotype V/V (P<.01). However, this genotype was not an independent risk factor for PPS. The FcgammaRIIA and IIIB genotypes and allele frequencies did not differ between the patients and control subjects. The FcgammaRIIIA V/V genotype may lower the risk for contracting acute poliomyelitis through better clearance of poliovirus.

Interleukin-10 promoter polymorphisms in patients with multiple sclerosis

The expression level of interleukin-10 (IL-10) is related to polymorphisms -1082 (G/A), -819 (T/C) and -592 (A/C) in the promoter region of the IL-10 gene. The distribution of these polymorphisms was analyzed to determine whether they could influence disease susceptibility or clinical course in multiple sclerosis (MS). The -1082 (G/A), -819 (T/C) and -592 (A/C) genotypes were similarly distributed between MS patients and the controls. The primary progressive MS patients with the low IL-10 expression haplotype showed a trend towards a worse clinical outcome than did patients with medium- or high-expression haplotypes (P = 0.056). The polymorphisms did not influence the clinical course in patients with relapsing-remitting MS.

TNF-alpha and -beta gene polymorphisms in multiple sclerosis: a highly significant role for determinants in the first intron of the TNF-beta gene

Tumor necrosis factor (TNF)-alpha and TNF-beta are proinflammatory cytokines that have been implicated in the pathogenesis of several autoimmune diseases. The aim of this investigation was to determine whether a determinant in the first intron of the TNF-beta gene (TNF-beta(+252)) and two promoter-region polymorphisms of the TNF-alpha gene (TNF-alpha(-308) and TNF-alpha(-238)) affect susceptibility to multiple sclerosis (MS). DNA samples from 133 Caucasian MS patients and 148 healthy controls from Norway were genotyped for several polymorphic determinants, using polymerase chain reaction-based restriction fragment length polymorphisms (PCR-RFLP) methods. TNF-beta(+252) genotypes were significantly associated with MS: The frequency of TNF-beta 2,2 was increased (p = 0.00009) while the frequency of TNF-beta 1,2 was decreased (p = 0.0012) in MS patients as compared to controls. TNF-alpha genotypes were not associated with MS. These results suggest that the TNF-beta gene plays a significant role in the etiopathogenesis of MS.

Immunoglobulin G fc-receptor (FcgammaR) IIA, IIIA, and IIIB polymorphisms related to disease severity in rheumatoid arthritis

OBJECTIVE

Fc receptors for IgG (FcyR) modulate immune responses. FcyR are expressed on various leukocytes and contain allelic polymorphisms with different capacity for IgG binding and phagocytosis. We investigated the distribution of FcgammaRIIA, FcgammaRIIIA, and FcgammaRIIIB polymorphisms in rheumatoid arthritis (RA) and whether they were related to disease expression and severity.

METHODS

Ninety-six controls and 114 patients fulfilling American College of Rheumatology (ACR) criteria for RA were genotyped for FcgammaRIIA, IIIA, and IIIB using polymerase chain reaction. Physician's global assessment of RA type estimated RA disease expression. In addition, usual measures of disease activity were recorded.

RESULTS

The genotype and allele frequencies did not differ significantly between the RA patients and the controls. Patients homo or heterozygous for the FcgammaRIIA arginine (R) allele had significantly more aggressive RA and swollen joints than patients homozygous for the FcgammaRIIA histidine (H) allele. Although there was a tendency of more severe disease among patients homo or heterozygous for the FcgammaRIIIA valine allele, there were no significant findings with the disease activity for the FcgammaRIIIA and FcgammaRIIIB genotypes.

CONCLUSION

FcgammaRIIA is implicated as a possible disease modifying gene in RA. Individuals homozygous for the FcgammaRIIA R allele have less efficient binding of IgG2 subclasses than individuals homozygous for the H allele. Less effective processing of circulating immune complexes in RA patients homozygous for the FcgammaRIIA R allele may therefore contribute to a more unfavorable course.

[Molecular genetic diagnosis of Charcot-Marie-Tooth disease and hereditary neuropathy with liability to pressure palsies]

Charcot-Marie-Tooth (CMT) disease is the most commonly inherited disorder of the peripheral nervous system; in Norway, the estimated prevalence is approximately one in 2,500. CMT has been classified into a demyelinating form (CMT1) and an axonal form (CMT2). Around 70-80% of CMT1 cases are caused by a dominantly inherited 1.5 Mb duplication at 17p11.2-12 (CMT1A), encompassing the peripheral myelin protein 22 (PMP22) gene. In contrast, hereditary neuropathy with liability to pressure palsies (HNPP) is caused by the reciprocal deletion of the same 1.5 Mb region. We recently developed a method by real-time quantitative polymerase chain reaction (PCR) for detecting CMT1A duplication and HNPP deletion. Real-time quantitative PCR is very sensitive for identifying PMP22 gene copy number in CMT1A duplication and HNPP deletion. We discuss molecular genetic testing of CMT1A duplication and HNPP deletion. Real-time quantitative PCR should find broad application in clinical and research settings, not only in CMT1A duplication and HNPP deletion, but also in other diseases involving gene copy number or gene expression.

Fcgamma receptor polymorphisms in populations in Ethiopia and Norway

Seventy-seven healthy Ethiopians were genotyped for polymorphisms in the immunoglobulin G Fc receptors (FcgammaR) FcgammaRIIa, FcgammaRIIIa and FcgammaRIIIb, including the SH allele. The genotype and allele frequencies were compared with those of 96 healthy Norwegians. Ethiopians had higher frequencies of the SH-FcgammaRIIIb (P = 0.001), FcgammaRIIIa-158 V (P = 0.026) and FcgammaRIIIb-Na2 (P = 0.046) alleles. The genotype distributions of FcgammaRIIa, FcgammaRIIIa and FcgammaRIIIb, however, did not differ significantly from those of the Norwegians. The data were also compared with those reported from studies on other ethnic groups. The variation of different polymorphisms both within and between ethnic groups may influence differences in the incidence rates of infectious and autoimmune diseases.

Fc receptors for immunoglobulin G--a role in the pathogenesis of Guillain-Barré syndrome and multiple sclerosis

Receptors for the Fc part of IgG (FcgammaR) constitute a family of cell-surface molecules expressed on almost every cell of the immune system. They are also present on non-lymphoid cells such as Schwann cells and endothelial cells. By linking humoral and cell-mediated responses, FcgammaR are key in defending against pathogens. Polymorphisms in some FcgammaR genes are associated with infectious and autoimmune diseases. It was found recently that certain FcgammaRIIA and FcgammaRIIIB allotypes are correlated with the disease course of Guillain-Barré syndrome (GBS) and multiple sclerosis (MS). This may imply that clearance of circulating autoantibodies and immune complexes is important in the pathogenesis of these diseases.

Recombination breakpoints in the Charcot-Marie-Tooth 1A repeat sequence in Norwegian families

OBJECTIVE

To investigate the recombination breakpoint in a 3.2 kb junction fragment of the 24 kb CMT1A repeat sequences (CMT1A-REPs) on chromosome 17p11.2-12.

MATERIALS AND METHODS

Thirty-eight Norwegian CMT1 patients and 15 asymptomatic family members of 15 separate families including 10 normal controls were investigated using repeat (REP)-PCR.

RESULTS

Twenty-six (68.4%) of the CMT1 patients from 9 (60%) families were positive for the CMT1A duplication which was not found in any of the controls. In 89.9% of the REP-PCR positive families the recombination breakpoint was mapped to a 1.7 kb "hot-spot" region, and in 11.1% of the families to a 1.5 kb region telomeric to the 1.7 kb region.

CONCLUSION

The frequency and regions for CMT1A-REPs crossover events in Norwegian CMT1A cases are similar to what is found in other populations. REP-PCR is not, however, as sensitive as other diagnostic methods to detect the CMT1A duplication.

Molecular genetic analysis of Charcot-Marie-Tooth 1A duplication in Norwegian patients by quantitative photostimulated luminescence imaging

Around 70% of Charcot-Marie-Tooth 1 (CMT1) cases are caused by a dominantly inherited 1.5-Mb duplication at 17p11.2-12 (CMT1A). Using photostimulated luminescence (PSL) imaging of MspI Southern blots, hybridization signals of the probe pVAW409R3a in relation to cohybridized probe SF85a, were densitometrically quantified and an RFLP allele-band ratio determined. A total of 55 Norwegian CMT patients and 16 asymptomatic family members from 26 separate families, clinically and neurophysiologically classified as CMT1 (n=46) and CMT2 (n=9), were studied. Thirty-two of 46 CMT1 cases (69.6%), all heterozygous but one homozygous for the pVAW409R3a MspI polymorphism, from 12 of 21 families (57.1%) were positive for the CMT1A duplication. In autosomal dominant familial cases (n=30), 26 of 30 cases (86.7%), all heterozygous, from six of seven families (85.7%) were positive for duplication. None of the CMT2 patients, asymptomatic family members or healthy controls were positive for duplication. The CMT1A frequency of duplication in Norwegian CMT1 patients is in general agreement with those reported in other European countries and the present results show that quantitative densitometric PSL imaging is a highly reliable test in diagnosing CMT1A duplication.

[Neuromuscular complications of sepsis]

BACKGROUND

Neuromuscular complications are common in patients treated for sepsis and multiple organ dysfunction in critical care units. Failure to wean from the ventilator, due to involvement of the respiratory system, and severe muscular weakness are typical symptoms. Electrophysiological examination demonstrates fibrillation potentials and reduction of compound muscular action potential amplitudes.

MATERIAL AND METHODS

We report three patients with severe muscular weakness during treatment of critical illness.

RESULTS

Critical illness polyneuropathy was the main cause of weakness in two patients, with a presumed superimposed myopathy in one. A third patient had critical illness myopathy.

INTERPRETATION

Critical illness polyneuropathy and myopathy--either as separate or combined entities--are common causes of muscular weakness during treatment of critical illness. These disorders are often difficult to distinguish from each other, as the clinical and electrophysiological findings may overlap. Sepsis and multiple organ dysfunction are the main aetiological factors, but certain drugs may contribute in the pathogenesis. No specific treatment exists. In the most severe cases long-lasting physiotherapy and rehabilitation is needed.

[Neuromuscular complications of myxoma]

BACKGROUND

Myxomas are the most common type of primary cardiac tumours. As they are most often located in the left atrium, primary neurological manifestations are often multiple embolic infarcts in the central nervous system.

MATERIAL AND METHODS

We describe a patient with acute aphasia due to left temporal haemorrhage. Later he developed acute ataxia due to right cerebellar infarct.

RESULTS

Magnetic resonance also showed multiple supra- and infratentorial infarcts. Echocardiography revealed a myxoma in the left atrium which was treated by surgical excision. There were no signs of myxoma recurrence or embolic infarcts at follow-up.

INTERPRETATION

Echocardiography should be included in the diagnostic work-up of patients with cerebrovascular events, especially in young patients with multiple infarcts.

Neutralizing antibodies to interferon (IFN) alpha-2a and IFN beta-1a or IFN beta-1b in MS are not cross-reactive

Sera from patients with MS treated with recombinant interferon (rIFN) alpha-2a, rIFNbeta-1a, or rIFNbeta-1b were analyzed for cross-reacting neutralizing antibodies (NAB). Because cross-reactivity was not found, switching treatment from rIFNbeta-1a or rIFNbeta-1b to rIFNalpha-2a might provide a secondary treatment response in patients with NAB to rIFNbeta-1a or rIFNbeta-1b. A positive treatment response also might be achieved by switching NAB rIFNalpha-2a-positive patients to rIFNbeta-1a or rIFNbeta-1b.

Real-time quantitative polymerase chain reaction. A new method that detects both the peripheral myelin protein 22 duplication in Charcot-Marie-Tooth type 1A disease and the peripheral myelin protein 22 deletion in hereditary neuropathy with liability to pressure palsies

In Charcot-Marie-Tooth type 1A disease (CMTIA), heterozygosity for the peripheral myelin protein 22 (PMP22) duplication increases the gene dose from two to three, whereas, in hereditary neuropathy with liability to pressure palsies (HNPP), heterozygosity for the PMP22 deletion reduces the gene dose from two to one. Thirty-eight Norwegian patients with CMT1, 4 patients with HNPP, 15 asymptomatic family members, and 45 normal controls were studied using the ABI 7700 sequence detection system and the TaqMan method of real-time quantitative polymerase chain reaction (PCR). Using a comparative threshold cycle (Ct) method and albumin as reference gene, the gene copy number by PMP22 gene duplication or deletion on chromosome 17p11.2-12 was quantified. The PMP22 duplication ratio ranged from 1.50 to 2.21, the PMP22 deletion ratio ranged from 0.44 to 0.55, and the PMP22 ratio in normals ranged from 0.82 to 1.27. All samples were run in triplicate, with a mean standard deviation of 0.07 (range 0.01-0.17). Thirty-four of thirty-eight CMT1 patients (89.6%) had the PMP22 duplication and the four HNPP patients had the PMP22 deletion. This was not found in any of the asymptomatic family members or the controls. Real-time quantitative PCR is a sensitive, specific, and reproducible method for diagnosing PMP22 duplication and deletion. The method is fast, allowing 13 patients to be diagnosed in 2 h. It involves no radioisotopes and requires no post-PCR handling. In our opinion, real-time quantitative PCR is the first method of choice in diagnosing PMP22 duplication and deletion.

Oligoclonal bands in cerebrospinal fluid: a comparative study of isoelectric focusing, agarose gel electrophoresis and IgG index

OBJECTIVE

To compare the sensitivity and specificity of isoelectric focusing (IEF) with immunofixation, agarose gel electrophoresis (AGE) and the IgG index in detecting intrathecally synthesized IgG in multiple sclerosis (MS) and in other nervous system disorders.

MATERIALS AND METHODS

Cerebrospinal fluid (CSF) and serum from 147 patients with various nervous system diseases, 20 of whom had MS, were compared with IEF, AGE and the IgG index.

RESULTS

CSF-restricted oligoclonal bands (OCB) were found in 20 of 20 patients with MS using IEF and in 9 of 20 using AGE. OCB were found in 12 patients with other nervous system disorders (OND) using IEF and 4 using AGE. The mean IgG index was 0.50 in OND and 0.96 in MS (P< 0.0001). Of 20 MS patients, 9 had an IgG index above the defined cut-off value of 0.72.

CONCLUSIONS

IEF is about twice as sensitive as AGE in detecting OCB in MS. IEF is also far superior to the IgG index in determining intrathecal IgG synthesis.