The value of an enzyme-linked immunosorbent assay for the diagnosis of schistosomiasis mansoni myeloradiculopathy

The role of serological tests on cerebrospinal fluid (CSF) in the diagnosis of neuroschistosomiasis has not been fully elucidated; the condition is essentially diagnosed on the basis of circumstantial evidence, which may lead to an erroneous diagnosis, especially in highly endemic areas. We therefore carried out a prospective case-control study in which we compared the concentrations of immunoglobulin G (IgG) specific for schistosome soluble egg antigen (SEA) present in the CSF of 54 patients with schistosomiasis mansoni myeloradiculopathy (SMMR) with those observed in a control group consisting of 41 patients with epidemiological and serological evidence of exposure to schistosomes, and with other neurological disorders that result in mild to moderate impairment of the blood-brain barrier. Anti-SEA IgG was estimated by an enzyme-linked immunosorbent assay. The sensitivity, specificity and positive and negative predictive values were 56%, 95%, 94% and 62% respectively. Likelihood ratios and the corresponding post-test probabilities were determined for 4 levels of anti-SEA IgG in CSF. A value below 0.1 micrograms/mL practically excluded the possibility of SMMR (post-test probability < 5%), a value above 1.4 micrograms/mL practically confirmed the diagnosis of SMMR (post-test probability > 96%), values of 0.1 to 0.5 microgram/mL had no diagnostic value (post-test probability approximately 45%), and values of 0.6 to 1.4 micrograms/mL were useful in some situations (post-test probability approximately 70%). We conclude that the estimation of anti-SEA IgG in the CSF is useful for the diagnosis of SMMR.

[Beta-2 microglobulin in cerebrospinal fluid in neurology]

OBJECTIVES

beta 2-microglobulin (beta 2-m) is a small molecular weight protein (11 800 Daltons) which can transudate into the cerebrospinal fluid (CSF) in the same manner than albumin. Intrathecal synthesis is a sign of local immuno-stimulation and is correlated with immunoglobulin G. The aim of this study was to ascertain the relationship between beta 2-microglobulin levels in the CSF and neurological diseases.

METHODS

beta 2-microglobulin was assayed in the CSF and blood using an immunoenzyme method in 64 patients with multiple sclerosis (n = 14), human immunodeficiency virus (HIV) infection (n = 5), meningitis (n = 12) or a peripheral neurological disease (n = 10) and in 7 control subjects.

RESULTS

There was no overall correlation between beta 2-m in the CSF and blood levels (r = 0.35). In controls, beta 2-m CSF and blood levels were respectively 0.94 +/- 0.22 and 1.46 +/- 0.83 mg/l. beta 2-m was significantly higher in the CSF of patients with meningitis and in the HIV positive patients (4 +/- 3.5 and 3.69 +/- 2.06 mg/l respectively) (p < 0.05). Type of meningitis (bacterial or non-bacterial) had no effect on the CSF level. For the HIV patients, the CSF/blood ratio for beta 2-m was similar to that in controls due to a rise in both blood and CSF. Finally, in patients with multiple sclerosis, there was no significant change in CSF level of beta 2-m.

CONCLUSION

beta 2-microglobulin in cerebrospinal fluid was not found to be correlated with the neurological diseases studied and cannot be used as a diagnostic test.

Heat shock protein immunoreactivity in CSF: correlation with oligoclonal banding and demyelinating disease

The detection of raised immunoglobulin and the presence of oligoclonal bands (OCBs) on electrophoresis of multiple sclerosis (MS) CSF has been a useful diagnostic test, but a universal antigen to which these MS antibodies are directed has yet to be found. Potentially immunogenic heat shock proteins (HSPs) are preferential expressed in vitro in human oligodendrocytes compared with other glia, and in situ in oligodendrocytes found within the plaques of MS. Immunoreactivity directed against HSPs might therefore contribute to the immune-mediated demyelinating process found in MS. We examined this possibility by quantitatively (ELISA) measuring antibodies directed against a recombinant human HSP (HSP60) in CSF from 18 MS patients, and compared them with eight patients with acute disseminated encephalomyelitis, 12 with demyelinating peripheral neuropathies, and 59 with other neurologic diseases. Immunoblotting was used to confirm the specificity of the antibodies for binding to HSP60. We found a statistically significant correlation between antibody titers to HSP60 and the presence of OCBs in CSF. These results support the notion that HSP expression in the CNS, such as that observed in MS, may be immunogenic, leading to localized HSP antibody secretion. Such HSP-directed immunoreactivity could play a role in the pathogenesis of MS and other immune-mediated disorders of the nervous system.

Effect of betaine on S-adenosylmethionine levels in the cerebrospinal fluid in a patient with methylenetetrahydrofolate reductase deficiency and peripheral neuropathy

A 16-year-old Japanese girl with 5,10-methylenetetrahydrofolate reductase deficiency showed peripheral neuropathy. There were no significant responses to vitamin B6, vitamin B12 or folate, given alone or in combination. With the addition of betaine monohydrate, she has been free from gait disturbance and muscle weakness. The concentration of S-adenosylmethionine in cerebrospinal fluid, which was undetectable before receiving betaine monohydrate, increased to about the normal level 24 months after treatment with betaine monohydrate.

Laboratory diagnosis of radicular and pseudoradicular syndromes in cerebrospinal fluid (CSF): reliability of methods in consideration of pathogenetic aspects. Report on section "CSF diagnosis" of 4th Klagenfurter Neurology Workshop Conference on radicular and pseudoradicular syndromes, Klagenfurt, Austria, August 28-29, 1992

Laboratory tests may be used to confirm the clinical differentiation of pseudoradicular syndromes and radicular syndromes. In the presence of pseudoradicular syndromes, CSF and blood samples yield no positive results with either non-specific or specific methods. Radicular syndromes give rise to positive findings; using non-specific methods they can be subdivided into inflammatory and non-inflammatory forms, with and without blood-nerve barrier impairment. Non-specific quantities of CSF routine diagnosis are total protein, albumin, leukocyte counts and differential cell count, L-lactate, intrathecal -IgG, -IgA, -IgM and immunoglobulin-class oligoclonal bands. Oligoclonal bands enable the highly sensitive differentiation of non-inflammatory from subacute-chronically inflammatory forms of radicular syndromes. Most of the specific quantities are the subject of current research, e.g. bacterial antigens, D-lactate, cultivation tests, polymerase chain reaction tests and pathogen-specific oligoclonal bands. Pathomechanisms affecting the permeability of the blood-nerve barrier to increasing concentrations of protein and to leukocyte subsets possibly explain the CSF findings in radicular and pseudoradicular syndromes.

Paraneoplastic sensorimotor neuropathy associated with breast cancer

Paraneoplastic sensorimotor neuropathy occurs in association with many different types of cancer. The clinical findings are heterogeneous, and the pathogenesis is unknown. We have encountered 9 women with breast cancer and shared neurological features that suggest a distinct paraneoplastic syndrome. The syndrome is characterized by upper and lower extremity paresthesias and numbness, itching, muscle weakness and cramps, and in some, radicular symptoms and signs. Serum and CSF inflammatory changes suggested an immune pathogenesis but none had detectable antibodies directed at nervous system elements. Six patients presented with neuropathy 2 months to 8 years before the discovery of the breast cancer. In 7 the neoplastic disease was localized to the breast and axillary lymph nodes. The neurologic course was chronic in all, and while symptoms were annoying, disability was minimal until late. One improved transiently with plasmapheresis, and three had mild transient improvement with treatment of the cancer. Recognition of this paraneoplastic syndrome may forewarn the physician of an underlying breast malignancy.

Accelerated neuropathy of renal failure

OBJECTIVE

To describe a syndrome of rapidly evolving polyneuropathy in patients with severe renal failure.

DESIGN

Retrospective case series of four patients.

SETTING

In-hospital evaluations and personal examinations of patients.

PATIENTS

Four patients with severe or end-stage renal failure who were receiving peritoneal dialysis.

RESULTS

These patients had an acute or subacute syndrome characterized by generalized limb weakness over days or weeks, severe imbalance, diminished reflexes, and numbness. Spinal fluid protein levels were elevated and some demyelinating features were noted on electrophysiological testing. Improvement occurred with more frequent peritoneal dialysis in one patient and transplantation in another, but the neuropathy progressed in the other two in whom diabetes may have played a role.

CONCLUSION

This partly reversible acute uremic neuropathy, which is probably caused by the metabolic disturbances of end-stage renal failure, simulates Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy and may be complicated by diabetic neuropathy.

Elevation of human cerebrospinal fluid clusterin concentration is associated with acute neuropathology

Clusterin is a serum glycoprotein which is an inhibitor of complement and is expressed in many tissues in cell injury and death. It has been identified normal and pathological brain tissue and is a component of normal human cerebrospinal fluid (CSF). We have measured the clusterin concentration of 115 abnormal and normal human CSF samples and related these data to the patient's clinical diagnoses. CSF clusterin levels in patients with neurodegenerative and meningeal disease were within the normal range. Twelve of 15 patients with demyelination, however, had significant elevation of CSF clusterin concentration. This was not a specific finding for multiple sclerosis as elevated clusterin levels were also seen in patients with other acute neuropathology. Determination of CSF clusterin concentration may be of clinical value in neurological diagnosis.

Assessment of reliability and biological significance of glutamate levels in cerebrospinal fluid

The published information on glutamate levels in cerebrospinal fluid (CSF) and modifications in neurological disorders is controversial. In the present study, we demonstrated a metabolic instability of glutamate in untreated CSF and a spurious elevation of its levels by the current methods of CSF acidification. These findings may explain the discrepancies observed with different methods of CSF processing and analysis. We suggest a method of inactivating CSF enzymes that yields stable glutamate levels under different storage conditions. Use of such a method may be necessary for clinical studies.

The significance of serum oligoclonal bands in neurological diseases

The presence of oligoclonal bands (OCBs) of immunoglobulin G (IgG) in CSF provides evidence for the occurrence of a humoral immune response, but it is not always appreciated that the oligoclonal IgG may have originated in the serum. To determine the diagnostic significance of serum OCBs 146 patients with serum OCBs were identified among 1874 patients with suspected neurological disorders (7.6%). Clear diagnoses had been made in 112 of these patients: in 56 identical CSF and serum bands were present, revealing a systemic immune response, while in 46 additional unique CSF bands indicated that intrathecal IgG synthesis was also occurring. In the first group neoplasia and peripheral neuropathies accounted for over 50% of the diagnoses, infections and systemic inflammatory disorders for 32%, and multiple sclerosis was diagnosed in only one case. These figures contrast considerably with those reported for patients with CSF OCBs alone. Diagnoses in the second group of patients, with unique CSF OCBs in addition to serum OCBs, resembled those among patients with CSF OCBs alone. Examining CSF and serum in parallel for OCBs of IgG provides more diagnostic information than examining CSF alone, and the latter is potentially misleading.

Cerebrospinal fluid norepinephrine, 3-methoxy-4-hydroxyphenylglycol and neuropeptide Y levels in Parkinson's disease, multiple system atrophy and dementia of the Alzheimer type

Neuropeptide Y, one of the most abundant polypeptides within the nervous system, is co-stored with catecholamines, especially norepinephrine (NE), thus suggesting its possible involvement in pathologies characterized by a noradrenergic impairment. In Parkinson's disease (PD), as well as in multiple system atrophy (MSA), a central noradrenergic deficit has been demonstrated, and in the dementia of Alzheimer type (DAT) an impaired noradrenergic transmission has been postulated. In this study we determined CSF NE and MHPG levels in 29 PD, 15 MSA, 22 DAT patients and in 36 controls, while CSF NPY-immunoreactivity (NPY-ir) levels were measured in 10 PD, 7 MSA, 10 DAT patients and 20 controls. PD, MSA, and DAT patients showed a significant reduction in CSF NPY-ir and NE levels compared with controls, while CSF MHPG levels resulted in a reduction in only the MSA group. Furthermore, an inverse correlation between either NE or MHPG levels and the duration of the orthostatic hypotension was found in MSA patients while for DAT patients the MHPG levels were directly correlated to the severity of cognitive impairment, and inversely to the duration of illness.

Experimental peripheral neuropathy decreases the dose of substance P required to increase excitatory amino acid release in the CSF of the rat spinal cord

Partial ligation of the sciatic nerve of rats produces hyperalgesia similar to that seen in humans following nerve injury. In this study, we used microdialysis of the spinal cord cerebral spinal fluid (CSF) to test the hypothesis that hyperalgesia is due to an enhanced release of excitatory amino acids (EAA) in response to substance P (SP). Intrathecal SP caused release of aspartate and glutamate in the CSF of rats with partial sciatic ligation at a dose of SP that did not cause release in sham operated animals. Neonatal capsaicin pretreatment blocked SP-induced EAA release in both sham and sciatic ligated animals. Release of EAAs in ligated animals was not significantly different from release in sham-operated animals following higher doses of SP or chemical nociceptive stimulation. These results demonstrate a partial sciatic ligation-induced decrease in the dose of SP required to initiate EAA release in the CSF of the spinal cord, a change which could play an important role in hyperalgesia.

Gangliosides of human cerebrospinal fluid in various neurologic diseases

Simultaneous profile determination and quantification of human cerebrospinal fluid (CSF) gangliosides in various neurologic diseases (n = 71) was examined. Gangliosides were extracted with methanol/chloroform from clinically available amounts of CSF (4-5 ml), then separated and quantified by high-performance thin-layer chromatography (HPTLC) and direct densitometry. Based on chromatographic comparison with standards, the percentage of lipid-bound NeuAc positive fractions in 'normal' CSF samples were: GM1 (II3 NeuAc-GgOse4Cer) (3%); GD3 (II3 NeuAc2-Lac-Cer) (4%); GD1a (IV3 NeuAc, II3 NeuAc-GgOse4 Cer) (15%); X1 (3%); GD1b (II3(NeuAc)2-GgOse4 Cer) (16%); X2 (4%); GT1b (IV3 NeuAc, II3(NeuAc)2-GgOse4-Cer) (40%); and GQ1b (IV3(NeuAc)2, II3(NeuAc)2-GgOse4-Cer (15%). Similarity between CSF and CSF and human cerebellar cortex, particularly in proportion of "b" series gangliosides (GQ1b, GT1b, GD1b), could be observed. A higher proportion of GD1a ganglioside, with decreased GQ1b was found in infancy. The total ganglioside content (mean +/- 2 SD) varied between 645-894 micrograms/l. Significant alterations of the CSF ganglioside profile, with an increase in less polar gangliosides, GM3 and GD3, correlated with the blood-brain barrier dysfunction (CSF hemorrhages, compressive syndrome), or some malignant processes (metastatic brain melanoma). A statistically significant increase in the content of total CSF gangliosides was found in the following groups of patients as compared to controls: (1) ischemic cerebrovascular accident (CVI) with good outcome (P less than 0.02); (2) peripheral neuropathy and polyneuropathy (P less than 0.001) and (3) intravertebral discopathy (P less than 0.05). A significant decrease in the content of total CSF gangliosides was found in CVI group with lethal outcome (P less than 0.05).

Class II antigen expression in peripheral neuropathies

The expression of class II antigen was studied in sural nerve biopsies from patients with peripheral neuropathies. These included patients with chronic demyelinating polyradiculoneuropathy (CIDP), non-immune mediated neuropathies of diverse etiologies and controls without evidence of neuropathy. The major finding in CIDP was a marked increase in class II expression on Schwann cells. Endoneurial Schwann cell staining to the same degree as in CIDP was seen in diabetic symmetric proximal motor neuropathy, neuropathies associated with monoclonal gammopathies and hereditary sensory and autonomic neuropathy type 1. In the control nerves and the other non-immune mediated neuropathies class II expression was mainly restricted to endothelial and perineurial cells. Increased endoneurial expression of class II antigen was found to correlate with elevated cerebrospinal fluid (CSF) protein levels but not with other clinical variables or demyelination as defined by electrophysiologic criteria or teased fiber analysis. The increased expression of class II antigen on Schwann cells may be indicative of a breakdown in immunological tolerance but should not be used as a diagnostic marker for dysimmune neuropathies due to overlap with non-immune mediated neuropathies.

[Serotonin and monoamine metabolites in cerebrospinal fluid in children: interrelationships and the influence of age, sex and precursor]

Cerebrospinal fluid and blood were taken from 15 non-neurologic children. Tryptophan(Trp), 5-HTP, 5-HT, 5-HIAA, HVA, MHPG in CSF, and 5-HT, free and total Trp(F-Trp and T-Trp) in serum were determined by HPLC method. Results showed that Trp, 5-HTP, 5-HT, 5-HIAA in CSF were positively correlated significantly. Good correlations were also found between F-Trp in serum and Trp in CSF (C-Trp), 5-HIAA and HVA, 5-HTP and MHPG. C-Trp, 5-HTP, 5-HT, 5-HIAA and HVA declined significantly with increasing age. MHPG was higher in male than in female children.

Antibodies to myelin-associated glycoprotein are found in cerebrospinal fluid in polyneuropathy associated with monoclonal serum IgM

Antibodies to myelin-associated glycoprotein (MAG) have been demonstrated in the serum samples from about half the patients with polyneuropathy associated with serum IgM monoclonal component. We examined cerebrospinal fluid (CSF) and serum samples from 13 patients with this disease by enzyme-linked immunosorbent assay for anti-MAG IgM antibodies. We detected these antibodies in both CSF and serum samples in 10 of the patients; in three of them the antibodies were at higher levels in the CSF. The remaining three patients had anti-MAG IgM antibodies in the CSF only. Intrathecal production of anti-MAG IgM antibodies is thus common in polyneuropathy associated with IgM monoclonal component. In three patients, examined on two occasions from 1 to 7 years, high anti-MAG IgM antibody levels persisted in CSF and serum samples. Among 165 patients with other neurologic diseases, including 60 with multiple sclerosis and 60 control subjects with tension headache, anti-MAG IgM antibodies were detected in the CSF from three patients (two with multiple sclerosis, one with aseptic meningitis), and in the serum sample of one patient with multiple sclerosis. Whether the frequent occurrence of anti-MAG IgM antibodies in CSF and their intrathecal synthesis has pathogenetic relevance for the development of polyneuropathy associated with IgM monoclonal component is unsure.

Peripheral neuropathy associated with eosinophilia-myalgia syndrome

In 1989, the Centers for Disease Control recognized the existence of an epidemic illness characterized by myalgia and eosinophilia in individuals taking preparations containing L-tryptophan. We evaluated 3 patients with eosinophilia-myalgia syndrome who presented with subacute progressive neuropathies. The neuropathies were predominantly motor and maximal in the lower extremities. Two patients were confined to a wheelchair and one was ventilator-dependent and bedridden. Sensory loss predominantly involved small fiber modalities. Electrophysiological studies showed multifocal marked conduction slowing and conduction block indicating segmental demyelination, with associated axonal degeneration that was accentuated distally. Examination of sural nerve biopsy specimens demonstrated axonal degeneration in all 3 patients and perivascular infiltrates in 2. Levels of quinolinic acid, a neurotoxic metabolite of L-tryptophan, were elevated in the cerebrospinal fluid in the 2 patients in whom it was measured. The cause of the neuropathy is unknown but may include immune mechanisms or toxicity of eosinophils, L-tryptophan, its metabolic products, or contaminants within L-tryptophan preparations.

Zinc, copper and magnesium concentration in serum and CSF of patients with neurological disorders

Zinc (Zn), copper (Cu) and magnesium (Mg) concentrations in cerebrospinal fluid (CSF) and serum were determined with atomic absorption spectrophotometry in 74 patients suffering from various neurological diseases, and in 28 healthy controls. Increased CSF zinc levels were found in the group of peripheral nervous system diseases (P less than 0.01) and in the cases of different neurological syndromes with increased CSF protein concentration (P less than 0.001). Increased CSF and serum copper levels were found in the cases with increased CSF protein levels (P less than 0.05). It is probable that the damaged blood-brain-barrier (BBB) permits the passage of the trace elements Zn, Cu and of Mg into the subarachnoid space. Decreased serum Cu levels (P less than 0.01) were found in the group of multiple sclerosis (MS). The findings are correlated to those of previous communications.

Evidence of central nervous system involvement in chronic demyelinating neuropathies associated with "benign" gammopathies

Recent papers underline the possible involvement of the central nervous system when an acquired peripheral demyelinating disease occurs and vice-versa. We describe five patients with chronic polyneuropathy and "benign" gammopathy, monoclonal (IgM-K, IgA-k, IgG-k) in three cases and polyclonal (IgG, IgM) in two cases; the monoclonal gammopathies were detected in cases of peripheral nerve disease. Three patients showed tremor and signs of pyramidal system impairment when the peripheral damage had improved or was stable. All cases underwent a longitudinal assessment according to clinical, CSF, EMG-ENG, neuroradiological and pathological criteria. The MRI finding always showed multiple alterations of encephalic white matter. When related to neurophysiological and pathological data supporting a chronic demyelinating neuropathy, such results point to possible encephalic involvement in chronic polyneuropathies due to a pathogenetic mechanism common to both.

Cerebrospinal fluid immunoreactive substance P and somatostatin in neurological patients with peripheral and spinal cord disease

We have measured substance P-like (SPLI) and somatostatin-like (SLI) immunoreactivities in cerebrospinal fluid of 49 patients with peripheral (polyneuropathy, lumboischialgia) and spinal cord disease and in 16 control patients. The patient groups showed significantly higher CSF SPLI levels than controls while the mean SLI levels were unchanged. Fractionated sampling of CSF (total volume 30 ml) in 20 patients with various neurological diseases showed no significant differences between early and late fractions for SLI. In contrast, lumbar-cisternal concentration gradients were negative for SPLI, total protein and IgG, and positive for the dopamine metabolite homovanillic acid and the serotonin metabolite 5-hydroxyindolacetic acid. This suggests that SPLI may be released into the lumbar CSF from lower levels of the neuraxis, presumably the spinal cord and spinal ganglia, whereas SLI stems from diffuse CSF secretion without spinal preponderance.

[Isoelectric focusing in neurological diagnosis]

The cerebrospinal fluid (CSF) of 1673 neurological patients in whom conventional agar electrophoresis failed to provide conclusive results was analyzed by isoelectric focusing (IEF). The primary aim of the study was not to analyze the frequency of oligoclonal immunoglobulins in the CSF of patients with inflammatory diseases of the central nervous system (CNS) but to answer the question how often, and in which particular disturbances, gamma-globulin changes typical of inflammatory processes are found in conditions which do not primarily belong to the group of inflammatory CNS diseases. It is shown that oligoclonal IgG bands in these circumstances are not common but did occasionally occur in most diagnostic groups. Results suggest increased frequency in certain groups such as Guillain-Barré polyradiculitis and in various neoplastic disorders. The diagnostic difficulties resulting from these findings and the advantages of IEF over the more generally favoured "Ig-index" are discussed. In addition, we report on the occasional appearance of monoclonal IgG gammopathies either associated with inflammatory CNS reactions or - more frequently - as an isolated and unexplained finding.

Syphilitic polyradiculopathy in an HIV-positive man

We report a case of syphilitic lumbosacral polyradiculopathy in an HIV-positive, 22-year-old bisexual man with a recent history of secondary syphilis treated with intramuscular penicillin. He presented with rapidly progressive pain and weakness, and muscle wasting in the legs. CSF was under increased pressure and showed a marked pleocytosis (1,130 cells/mm3), hypoglycorrhachia (19 mg/dl), and very elevated protein (1,000 mg/dl). Serum and CSF VDRL serologies were positive. In the legs, nerve conduction studies and needle EMG were consistent with an asymmetric lumbosacral polyradiculopathy with active denervation. His clinical state, CSF, and electrophysiologic studies all improved promptly and markedly after intravenous penicillin. This report documents an uncharacteristically aggressive case of neurosyphilis accompanied by marked changes in the CSF in an HIV-positive patient. While the immunologic effects of HIV and syphilis in combination are not yet fully understood, the cellular immunity defect associated with HIV may alter the natural history of syphilis in patients with concomitant infection, producing unusually aggressive forms or atypical presentations of neurosyphilis.

Long-term administration of 3'-azido-2',3'-dideoxythymidine to patients with AIDS-related neurological disease

3'-Azido-2',3'-dideoxythymidine (AZT) has been administered to 7 patients with human immunodeficiency virus-associated neurological disease: 3 with dementia, 2 with peripheral neuropathy, 1 with dementia and peripheral neuropathy, and 1 with T-10 paraplegia. Six of the patients showed improvement in their neurological dysfunction on being administered AZT, as assessed by clinical evaluation, neuropsychological testing, nerve conduction studies, and/or positron emission tomographic scans. Three of these 6 patients showed sustained improvement 5 to 18 months after the initiation of AZT therapy. These results suggest that certain human immunodeficiency virus-associated neurological abnormalities are at least partially reversible following the administration of antiretroviral therapy and provide a rationale for further studies using antiretroviral chemotherapy.

Visual evoked potentials in patients with neuropathy and macroglobulinemia

Visual evoked potentials were studied in 11 patients with neuropathy and macroglobulinemia. The P100 latency was increased bilaterally in 5 of the 6 patients whose IgM M-proteins reacted with myelin-associated glycoprotein (MAG) and in 1 of the other patients. In patients whose M-protein bound to MAG, abnormal visual evoked potentials correlated with the presence of the M-protein in the cerebrospinal fluid. Subclinical involvement of the central nervous system is frequent in patients with neuropathy and anti-MAG M-proteins and may be due to the binding of M-proteins to central nervous system myelin.

Variant transthyretin in cerebrospinal fluid in familial amyloidotic polyneuropathy

Structurally abnormal transthyretin is a precursor protein of amyloid fibrils in type I familial amyloidotic polyneuropathy (FAP). This variant transthyretin has an amino acid substitution of methionine for valine at position 30. The purpose of this study was to clarify whether this variant transthyretin also circulates in the cerebrospinal fluid (CSF) of patients with type I FAP. CSF transthyretin of the patients was purified and its primary structure determined. Sequence determination indicated that transthyretin consisted of a mixture of normal and variant transthyretin. Variant transthyretin was present in the CSF of all 5 Japanese FAP patients studied. The CSF concentration of variant transthyretin was high (0.72 +/- 0.15 mg/dl, mean +/- S.D.), suggesting that variant transthyretin is synthesized in the choroid plexus. Variant transthyretin was not present in any of 20 controls. The CSF concentration of total transthyretin in FAP patients was 1.74 +/- 0.42 mg/dl, which was not significantly different from controls.