Thymus histology and concomitant autoimmune diseases in Japanese patients with muscle-specific receptor tyrosine kinase-antibody-positive myasthenia gravis.

BACKGROUND AND PURPOSE: The differences in the characteristics of thymus histology, coexisting autoimmune diseases and related autoantibodies between anti-muscle-specific receptor tyrosine kinase (MuSK)-antibody (Ab)-positive myasthenia gravis (MG) patients, and anti-acetylcholine receptor (AChR)-Ab-positive MG patients are not clearly defined. METHODS: The types of thymus histology, coexisting autoimmune diseases and associated Abs in 83 MuSK-Ab-positive patients nationwide were investigated and were compared with those in AChR-Ab-positive patients followed at our institute (n = 83). As for the autoantibodies associated with thymoma, titin Abs were measured. RESULTS: Thymoma was not present in any of the MuSK-Ab-positive patients but presented in 21 patients (25.3%) amongst the AChR-Ab-positive patients. Titin Abs were absent in MuSK-Ab-positive patients but positive in 25 (30.1%) of the AChR-Ab-positive patients. Concomitant autoimmune diseases were present in eight MuSK-Ab-positive patients (9.6%) amongst whom Hashimoto's thyroiditis and rheumatoid arthritis predominated, whereas 22 AChR-Ab-positive patients (26.5%) had one or more concomitant autoimmune diseases of which Graves' disease predominated. CONCLUSIONS: Differences in frequency of thymoma and thymic hyperplasia, coexisting autoimmune diseases and autoantibody positivity between MuSK-Ab-positive and AChR-Ab-positive MG were indicated, suggesting that, in contrast with AChR-Ab-positive MG, thymus does not seem to be involved in the pathogenic mechanisms of MuSK-Ab-positive MG.

Anti-cyclic citrullinated peptide antibody (anti-CCP antibody) is present in the sera of patients with dementia of Alzheimer's type in Asian.

BACKGROUND: In the hippocampi of Alzheimer's disease (AD) patients, aberrant expression of citrullinated proteins and peptidylarginase 2 (PADI2) has been identified. We explored the functional roles of these proteins by means of detection of serum anti-cyclic citrullinated peptide antibody (anti-CCP antibody) in patients with dementia of Alzheimer's type (DAT). METHODS: Sera were obtained from 42 patients with DAT, 30 patients with other neurological disorders and 42 healthy controls. Gender ratio and age were comparable among the three groups. The level of anti-CCP antibody in sera was examined by ELISA. FINDINGS: Anti-CCP antibody was not found in the 30 patients with other neurological disorders, and only one of the 42 healthy controls (2.4%) was positive. However, surprisingly, anti-CCP antibody was clearly detected in eight of the 42 DAT patients. INTERPRETATION: Anti-CCP antibody appears to be a simple and early serologic biomarker for DAT among dementia patients. Additionally, our data imply that citrullinated proteins accumulated in the astrocytes of AD patients acquire neo-antigenicity, inducing anti-CCP antibody production.

Experimental autoimmune myasthenia gravis: a sequential and quantitative study of the neuromuscular junction ultrastructure and electrophysiologic correlations.

Neuromuscular junction ultrastructure in rat forelimb digit extensor muscle was sequentially and quantitatively investigated in experimental autoimmune myasthenia gravis (EAMG). Experimental animals were immunized with highly purified eel electroplax acetylcholine receptor protein plus complete Freund's adjuvant and B pertussis vaccine; control animals received only adjuvant and vaccine. During the first 7 days (latent period) after immunization end-plate structure and neuromuscular transmission remained normal in the experimental group. Between day 7 and 11 (acute phase) mononuclear cells infiltrated those regions of muscle where the end-plates were located and there was intense degeneration of the postsynaptic regions with splitting away of abnormal junctional folds from the underlying muscle fibers. Macrophages entered the gaps thus formed and removed the degenerating folds by phagocytosis. The nerve terminals were displaced from their usual location but maintained their structural integrity. Neuromuscular transmission was blocked in many muscle fibers. Miniature end-plate potentias (MEPPs), detectable in only a few fibers, were of abnormally low amplitude. After day 11 (chronic phase) the nerve terminals returned to the highly simplified postsynaptic folds became reconstituted and again degenerated. Immature junctions with poorly differentiated postsynaptic regions and nerve sprouts near end-plates were also observed. In two animals relapsing during the chronic phase degeneration of the postsynaptic folds was more intense than in the other chronic-phase animals. The posysynaptic membrane length and length per unit area and the MEPP amplitudes were significantly decreased in all chronic phase animals and the decreases were greater in the relapsing than in the non-lapsing animals. Minor morphometric alterations were also observed in the nerve terminals. These might have been secondary to the postsynaptic changes. The postsynaptic region is the primary target of the autoimmune reaction in EAMG. The ultrastructural, morphometric and electrophysiological abnormalities of the end-plate in chronic EAMG resemble those which have been observed in human myasthenia gravis.

Increased adherence of T cells to human endothelial cells in patients with human T-cell lymphotropic virus type I-associated myelopathy.

We investigated the adherence of T cells to human umbilical vein endothelial cells in seven patients with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy. The adherence of T cells to endothelial cells increased significantly in all the patients with HTLV-I-associated myelopathy when compared with the adherence in the seronegative controls (1.3- to 2.8-fold) and compared with the adherence in the anti-HTLV-I-seropositive non-HTLV-I-associated myelopathy carriers (1.4- to 2.8-fold). Prior treatment of the endothelial cell monolayer with recombinant interferon gamma (50 IU/mL) enhanced the T cell-endothelial cell adhesion in both the controls and patients with HTLV-I-associated myelopathy. However, values after prior treatment in the patients with HTLV-I-associated myelopathy were significantly higher than those in seronegative controls and carriers. The results suggest that the significantly increased T cell-endothelial cell adherence may be related to the initial stages of lymphocyte migration from the blood to the central nervous system in patients with HTLV-I-associated myelopathy.

Characterization of HTLV-I in a T-cell line established from a patient with myelopathy.

We have established an interleukin 2-dependent, OKT4-positive T-cell line, named HCT-1, from cells in the cerebrospinal fluid obtained from a patient with human T-cell lymphotropic virus type I (HTLV-1)-associated myelopathy. Antigens for HTLV-I were detected in HCT-1 cells by indirect immunofluorescence and Western blot testing, and type C virus particles were detected by electron microscopy. Southern blot analysis of HCT-1 cellular DNA, using an HTLV-I probe, revealed that the integrated provirus genome could not be distinguished from the HTLV-I genome in adult patients with T-cell leukemia.

Retrovirus from human T-cell leukemia virus type I-associated myelopathy is the same strain as a prototype human T-cell leukemia virus type I.

A retrovirus was isolated from a T-cell line that was established from lymphocytes in the cerebrospinal fluid of a patient with human T-cell leukemia virus type I-associated myelopathy (HAM), and its genome was sequenced. The nucleotide sequence of the 3' half of the total genome was identical in 99.5% of the nucleotides to that of the prototype human T-cell leukemia virus type I that was derived from a patient with adult T-cell leukemia. These results indicate that the same retrovirus human T-cell leukemia virus type I is associated with both a neurological disease, HAM, and a lymphoproliferative disease, adult T-cell leukemia.

Exaggerated messenger RNA expression of inflammatory cytokines in human T-cell lymphotropic virus type I-associated myelopathy.

OBJECTIVE: To investigate the expression of inflammatory cytokine messenger RNA (mRNA) in peripheral blood mononuclear cells of patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM). PATIENTS: Seventeen patients with HAM, 18 HTLV-I-seropositive carriers, and 10 seronegative individuals were studied. MAIN OUTCOME MEASURE: We compared the expression of tumor necrosis factor alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon alpha (IFN-alpha), IFN-beta, and IFN-gamma, and interleukin 1 alpha (IL-1 alpha) and IL-1 beta by reverse transcriptase-polymerase chain reaction. RESULTS: In patients with HAM, the reverse transcriptase-polymerase chain reaction products of TNF-alpha, GM-CSF, IFN-gamma, and IL-1 alpha were detected in significantly higher incidences than in HTLV-I-seropositive carriers and seronegative controls. Furthermore, simultaneous mRNA expression of three or more of these four cytokines was detected in all patients with HAM compared with only 21.4% of HTLV-I-seropositive carriers. By contrast, there was no significant difference in mRNA expression of IFN-alpha, IFN-beta, and IL-1 beta among patients with HAM, HTLV-I-seropositive carriers, and HTLV-I-seronegative controls. CONCLUSIONS: An exaggerated mRNA expression of several inflammatory cytokines, including TNF-alpha, GM-CSF, IFN-gamma, and IL-1 alpha, was demonstrated in peripheral blood mononuclear cells of patients with HAM. Moreover, transcripts of these cytokines were simultaneously up-regulated in patients with HAM, suggesting that an inflammatory state in the central nervous system may be related to the pathogenesis of HAM.

Active state properties of denervated and immobilized muscle: comparison with dystrophic muscle.

Possible roles of neurotrophic mechanisms and muscle activity in the contractile abnormalities of muscular dystrophy were studied by comparing human dystrophic muscle to denervated and immobilized muscle. As evident in denervated muscle from the decreased acceleration of twitch development (decreased active state intensity of shortening), and isoproterenol-induced decrease of twitch with shortened decay of the active state, part of the abnormality in the subcellular calcium transport system in dystrophic muscle seems to be influenced by disordered neural regulation. Other active state abnormalities relating to activation processes and contractile proteins in dystrophic muscle were also demonstrated in both denervated and immobilized muscle, with some being more marked in immobilized muscle. The findings indicate that a neurogenic hypothesis cannot entirely explain the pathogenesis of progressive muscular dystrophy.

Muscular dystrophy in six young girls.

Clinical and genetic studies were made on progressive muscular dystrophy in six young girls. No chromosome abnormality was observed in these patients. The pedigree of one case implied a sex-linked recessive trait, and clinical features were identical with Duchenne dystrophy. The clinical manifestations of two sisters in another family were less severe than in their brother with Duchenne dystrophy. The clinical differences among these three cases are well explained by the Lyon hypothesis. Three other cases were compatible with childhood muscular dystrophy of autosomal recessive inheritance.

Myasthenia gravis associated with Satoyoshi syndrome: muscle cramps, alopecia, and diarrhea.

We studied a woman who had evidence of myasthenia gravis at age 17. At age 19, she gradually developed alopecia and painful muscle spasms (Satoyoshi disease). Deposition of immune complexes (IgG, C3, and C9) was demonstrated at the motor endplates of limb muscle (biceps brachii); primary synaptic clefts were widened, and postsynaptic folds were simplified. This is the first case of myasthenia and Satoyoshi disease in the same patient.

Ultrastructural localization of acetylcholine receptor at the motor endplate: myasthenia gravis and other neuromuscular diseases.

Peroxidase-conjugated alpha-bungarotoxin (P-BGT) was used for the ultrastructural localization of the acetylcholine receptor in motor endplates. Brachial biceps muscle specimens were obtained from six patients with myasthenia gravis (MG) (two ocular and four generalized), five other patients with neuromuscular diseases (limb-girdle dystrophy, polymyositis, and amyotrophic lateral sclerosis) and two controls. In all patients with generalized MG, most of the endplates showed a marked decrease in P-BGT binding. In one of two patients with ocular MG, the amount and distribution of P-BGT binding appeared normal, whereas the other patient showed a slight decrease in P-BGT binding. There was a loose correlation between clinical severity of MG and acetylcholine receptor index or antiacetylcholine receptor antibodies. On the other hand, the amount and distribution of acetylcholine receptor in other neuromuscular diseases was well preserved, even at the endplates denuded of their nerve terminals in amyotrophic lateral sclerosis (ALS) cases.

Limb muscle endplates in ocular myasthenia gravis: quantitative ultrastructural study.

Motor endplate ultrastructure in the biceps brachii was quantitatively analyzed in five patients with ocular myasthenia gravis (56 endplates), six patients with generalized myasthenia gravis (83 endplates), and five controls (64 endplates). Ultrastructural changes of the motor endplates were observed in nonweak limb muscles of patients with ocular myasthenia gravis as well as in generalized myasthenia; these changes were mostly restricted to the postsynaptic region. Decrease of the mean presynaptic and postsynaptic membrane length, and postsynaptic membrane density, were more remarkable in generalized myasthenia than in ocular myasthenia. Widening of the primary and secondary synaptic clefts was also observed more frequently in generalized myasthenia. There was no correlation between ultrastructural alterations and the duration of symptoms or treatment, severity of disease, or titers of antiacetylcholine receptor antibody.

Diagnostic significance of IgG, C3, and C9 at the limb muscle motor end-plate in minimal myasthenia gravis.

We detected deposits of IgG, C3, and C9 (immune complexes) at the limb muscle motor end-plates (biceps brachii muscle) in 16 of 19 patients who exhibited only ocular signs and symptoms of myasthenia gravis that were improved by intravenous injections of edrophonium chloride. Circulating anti-acetylcholine receptor (anti-AChR) antibodies were negative in 6 of the 16 patients, but the motor end-plate fine structure in the postsynaptic regions was abnormal in all 16. Single-fiber EMG revealed no abnormalities in 8 of 13 patients studied. Our results indicate that the detection of immune complexes at the limb muscle end-plate provides a highly sensitive and confirmative method for diagnosing patients with minimal or atypical myasthenia gravis who have no detectable anti-AChR antibodies in their serum.

Lewy body-type degeneration in cardiac plexus in Parkinson's and incidental Lewy body diseases.

Heart tissues of patients with PD or incidental Lewy body (LB) disease (ILBD) were examined by light and electron microscopy. LBs and alpha-synuclein-positive neurites were identified in the hearts from 9 of 11 patients with PD and from 7 of 7 patients with ILBD. LBs were present in both tyrosine hydroxylase-positive and -negative nerve processes, which are nerves of extrinsic sympathetic and intrinsic origin, respectively. These findings provide histologic evidence that the postganglionic sympathetic and intrinsic neurons in the heart are involved in the PD disease process.

Seronegative Lambert-Eaton myasthenic syndrome: study of 110 Japanese patients.

The authors characterized the clinical and immunologic features of 110 patients with Lambert-Eaton myasthenic syndrome (LEMS). Anti-P/Q-type voltage-gated calcium channels (VGCC) antibodies were detected in 85% of the patients (seropositive) but not in the rest (seronegative). Except for the indication that small cell lung carcinoma is less common in seronegative patients, no significant differences were found in the clinical characteristics of patients who had or did not have anti-P/Q-type VGCC antibodies. The results of passive transfer experiments suggest that seronegative LEMS is also an autoantibody-mediated disorder.

Active production of anti-human T-lymphotropic virus type I (HTLV-I) IgM antibody in HTLV-I-associated myelopathy.

We investigated the presence of anti-human T-lymphotropic virus type I (HTLV-I) IgM in sera and cerebrospinal fluid from patients with HTLV-I-associated myelopathy (HAM) by Western blot analysis. Analyses of 36 serum samples revealed that most patients (31/36; 86.1%) had anti-HTLV-I IgM, whereas only four of 23 (17.4%) HTLV-I carriers had it. In studies of cerebrospinal fluid, anti-HTLV-I IgM was detected in 24 of 36 (66.7%) HAM patients, whereas none was detected in nine HTLV-I carriers. The differences were statistically significant (p less than 0.01). These results suggest that persistent active replication of HTLV-I occurs in the central nervous system as well as in the peripheral blood of HAM patients, and may contribute to the development of HAM.

Loss of 123I-MIBG uptake by the heart in Parkinson's disease: assessment of cardiac sympathetic denervation and diagnostic value.

UNLABELLED: Myocardial imaging with 123I-metaiodobenzylguanidine (MIBG) was performed on 35 patients with Parkinson's disease and 24 control subjects to evaluate cardiac sympathetic function in patients with Parkinson's disease, verify this phenomenon and examine whether myocardial MIBG uptake and clearance are correlated with the clinical severity of Parkinson's disease. METHODS: We studied 35 patients with Parkinson's disease and 24 control subjects with other central nervous system diseases. The latter group consisted of 12 subjects with other neurodegenerative disorders (4 with spinocerebellar degeneration, 2 with amyotrophic lateral sclerosis, 3 with progressive supranuclear palsy and 3 with corticobasal degeneration and 12 patients with cerebral infarction (CI), 6 with vascular parkinsonism and 6 without it. Early and delayed images of the anterior view were obtained 15 min and 4 h after injection of 123I-MIBG, respectively. MIBG uptake was quantified by calculating a heart-to-mediastinum count (H/M) ratio. RESULTS: The H/M ratio was markedly reduced in the patients with Parkinson's disease (II to V on the Hoehn and Yahr scale) compared with the control subjects. None of the subjects with neurodegenerative diseases showed a marked decrease in myocardial MIBG uptake nor did any subject with CI. CONCLUSION: Our findings indicate that, in Parkinson's disease, a reduction in myocardial MIBG uptake is a very common, specific phenomenon that can be used to detect cardiac autonomic dysfunction to diagnose Parkinson's disease, particularly in patients without typical signs and symptoms.

The motor end plate in myasthenia gravis and in experimental autoimmune myasthenia gravis. A quantitative ultrastructural study.

Neuromuscular junction ultrastructure in rat forelimb digit extensor muscle was sequentially and quantitatively investigated in experimental autoimmune myasthenia gravis (EAMG). Experimental animals received a single dose of highly purified eel-electroplax acetylcholine receptor protein plus complete Freund's adjuvant and B. pertussis organisms. During the first 7 days (latent period) after immunization the experimental end plates remained normal. Between day 7 and 11 (acute phase) mononuclear cells infiltrated those regions of muscle where the end plates were located and the was sudden degeneration of the postsynaptic regions with splitting away of the abnormal junctional folds from the underlying muscle fibers. Macrophages entered the gaps arising between the muscle fibers and the separating postsynaptic folds and removed the degenerating folds by phagocytosis. The nerve terminals were displaced from their usual location but maintained their structural integrity. After day 11 (chronic phase) the inflammatory reaction subsided and the nerve terminals returned to the highly simplified postsynaptic regions. Subsequently the postsynaptic folds were reconstituted and again they degenerated. The degeneration involved especially the tips of the folds where acetylcholine receptor sites are concentrated. Immature junctions with poorly differentiated postsynaptic regions and nerve sprouts near end plates were also observed. In two animals that relapsed on day 27 and 33, respectively, degeneration of the postsynaptic folds was more intense than in the remaining animals that had not relapsed during the chronic phase. Morphometric analysis of the end plates demonstrated significant decreases in the postsynaptic membrane length, in the postsynaptic membrane density and in the postsynaptic to presynaptic membrane length ratio in chronic EAMG. In addition, the concentration of synaptic vesicles in the nerve terminals was increased in acute and chronic EAMG while the nerve terminal area was decreased in acute EAMG. The alterations in the nerve terminal may be secondary to the postsynaptic changes. The postsynaptic region is the primary target of the autoimmune reaction in EAMG and the ultrastructural and morphometric abnormalities of the end plate in the chronic phase of the syndrome closely resemble those which have been observed in human myasthenia gravis.

Specificity of omega-conotoxin MVIIC-binding and -blocking calcium channel antibodies in Lambert-Eaton myasthenic syndrome.

An immunoprecipitation assay was used to measure omega-conotoxin MVIIC (P/Q-type) binding and blocking calcium channel antibodies in 67 patients with Lambert-Eaton myasthenic syndrome (LEMS) and in a large control population. We first showed the presence of omega-conotoxin MVIIC-blocking antibody in LEMS patients. Binding antibodies were detected in 55 of 67 (82.1%) LEMS patients and in 2 of 296 (0.7%) controls. In contrast, blocking antibodies were positive in 14 of 67 (20.9%) LEMS patients and 8 of 171 (4.7%) controls. No LEMS patient had negative binding antibodies and positive blocking antibodies. The immunoprecipitation assay detected no antibodies against the whole P/Q-type calcium channel in either the paraneoplastic cerebellar degeneration or the amyotrophic lateral sclerosis sera. Neither the omega-conotoxin MVIIC-binding nor the -blocking calcium channel antibodies were correlated with clinical severity across the individuals, but longitudinal studies of some LEMS patients showed an inverse relation between binding antibody titre and disease severity. We concluded that the 125I-omega-conotoxin MVIIC assay for anti-P/Q-type voltage-gated calcium channel antibodies is highly specific for LEMS and that this sensitive binding antibody assay could be more valuable than the blocking antibody assay in the diagnosis of LEMS.

In vitro quantitative autoradiography of [125I]alpha-bungarotoxin binding at the motor end-plates of experimental autoimmune myasthenia gravis.

A quantitative evaluation was made of nicotinic acetylcholine receptors (AChR) at the motor end-plates in experimental autoimmune myasthenia gravis (EAMG). Female Lewis rats were immunized with AChR protein purified from electric organs of Narke japonica. The forelimb digit extensor muscle obtained in the chronic stage of the controls and EAMG were studied using [125I]alpha-bungarotoxin, in vitro and autoradiographically. The maximum binding capacity (Bmax) values of the controls and EAMG were calculated to be 237.7 +/- 13.0 fmol/mg (n = 4) and 42.0 +/- 4.1 fmol/mg (n = 4), respectively (P less than 0.001), and the dissociation constant (Kd) values were 11.7 +/- 1.6 nM and 7.6 +/- 0.9 nM, respectively. This in vitro autoradiographic method revealed a quantitative reduction of AChR at the motor end-plates in EAMG.