Increased levels of tau-like protein in patients with Down syndrome

Tau-like protein levels from 40 Down syndrome (DS) persons (31-70 years old), 40 non-DS age-matched normal controls, 18 non-DS mentally retarded (MR) persons (26-91 years old), 25 probable Alzheimer disease (AD) patients (55-99 years old) and 24 non-demented elderly controls (54-79 years old) were measured using a sandwich enzyme linked immunosorbent assay. The levels were detected in 22 of 40 DS persons and were significantly higher in DS than any other group (P < 0.0001). There was no relationship between tau-like protein levels and age, gender or apolipoprotein E phenotypes in any of the five groups.

Plasma amyloid beta-peptide 1-42 and incipient Alzheimer's disease

Mutations in the amyloid precursor protein and presenilin 1 and 2 genes result in elevated plasma levels of the amyloid beta-peptide species terminating at amino acid residue 42 (A beta1-42). In a longitudinal study of unrelated elderly individuals, those who subsequently developed Alzheimer's disease had higher plasma levels of A beta1-42 at entry than did those who remained free of dementia. The results indicate that elevated plasma levels of the released A beta peptide A beta1-42 may be detected several years before the onset of symptoms, supporting that extracellular A beta1-42 plays an important role in the pathogenesis of late-onset Alzheimer's disease.

Improved discrimination of AD patients using beta-amyloid(1-42) and tau levels in CSF

OBJECTIVE

To evaluate CSF levels of beta-amyloid(1-42) (Abeta42) alone and in combination with CSF tau for distinguishing AD from other conditions.

METHODS

At 10 centers in Europe and the United States, 150 CSF samples from AD patients were analyzed and compared with 100 CSF samples from healthy volunteers or patients with disorders not associated with pathologic conditions of the brain (CON), 84 patients with other neurologic disorders (ND), and 79 patients with non-Alzheimer types of dementia (NAD). Sandwich ELISA techniques were used on site for measuring Abeta42 and tau.

RESULTS

Median levels of Abeta42 in CSF were significantly lower in AD (487 pg/mL) than in CON (849 pg/mL; p = 0.001), ND (643 pg/mL; p = 0.001), and NAD (603 pg/mL; p = 0.001). Discrimination of AD from CON and ND was significantly improved by the combined assessment of Abeta42 and tau. At 85% sensitivity, specificity of the combined test was 86% (95% CI: 81% to 91%) compared with 55% (95% CI: 47% to 62%) for Abeta42 alone and 65% (95% CI: 58% to 72%) for tau. The combined test at 85% sensitivity was 58% (95% CI: 47% to 69%) specific for NAD. The APOE e4 gene load was negatively correlated with Abeta42 levels not only in AD but also in NAD.

CONCLUSIONS

The combined measure of CSF Abeta42 and tau meets the requirements for clinical use in discriminating AD from normal aging and specific neurologic disorders.

Decreases in plasma A beta 1-40 levels with aging in non-demented elderly with ApoE-epsilon 4 allele

This report examines plasma amyloid beta proteins A beta 40 and A beta 42 and apolipoprotein E (apoE) levels and their relationships with age in non-demented older adults with (N = 32) or without the apoE-epsilon 4 allele (N = 94). A beta levels did not differ between the groups whereas the epsilon 4 allele was associated with a significant reduction in plasma apoE. In subjects with the epsilon 4 allele, increasing age was associated with significant reduction in plasma A beta 40. Subjects without the epsilon 4 allele showed a significant positive correlation between A beta 40 and A beta 42 levels. There was also a significant correlation between plasma A beta 40 and apoE levels in all subjects.

Traumatic brain injury increases beta-amyloid peptide 1-42 in cerebrospinal fluid

The beta-amyloid peptides, A beta1-42 and A beta1-40, were quantified in ventricular CSF taken daily for up to 3 weeks from six individuals with severe traumatic brain injury (TBI). There was considerable interindividual variability in the levels of A beta peptides, but in general A beta1-42 levels equalled or exceeded those of A beta1-40. Averaging the daily totals of our trauma cohort revealed that the levels of A beta1-42 and A beta1-40 rose after injury, peaking in the first week and then declining toward control levels over the next 2 weeks. A beta1-42 levels were on average two to three times higher in the trauma cohort than in CSF from nontrauma samples. Compared with nontrauma samples, the A beta1-40/A beta1-42 ratio decreased about fivefold in the trauma patients, further indicative of increased A beta1-42 levels. The ratio remained low at all time points studied. No change was measured in the levels of beta-amyloid precursor protein during the same interval. These results suggest that A beta1-42 becomes elevated in the CSF after severe brain trauma.

The effects of age, apolipoprotein E phenotype and gender on the concentration of amyloid-beta (A beta) 40, A beta 4242, apolipoprotein E and transthyretin in human cerebrospinal fluid

OBJECTIVE

To test whether the concentrations of amyloid-beta (A beta) 40, A beta 42, apolipoprotein E (apoE) and transthyretin in the CSF of normal individuals, are linked to three factors which modulate the risk of Alzheimer's disease (AD): chronological age, gender, and the presence of the apoE4 allele.

METHODS AND RESULTS

Proteins were measured by enzyme-linked immunosorbent assays except for transthyretin, which was assayed by radial immunodiffusion. The apoE phenotype was determined by isoelectric focusing. While the CSF levels of A beta 42, apoE, and transthyretin are reported to be reduced in AD, we found no relationship between age, gene, or apoE phenotype and the level of any of these proteins in the CSF of nondemented individuals. The concentration of A beta 40 was not modulated by gender or apoE phenotype, but did decline significantly with age.

CONCLUSION

These results indicate that the changes observed in the CSF of AD patients are specific to the disease itself rather than the known risk factors.

Longitudinal study of cerebrospinal fluid amyloid proteins and apolipoprotein E in patients with probable Alzheimer's disease

Levels of soluble amyloid beta protein (sAbeta), amyloid beta precursor protein (APP) and apolipoprotein E (apoE) were examined in cerebrospinal fluid (CSF) obtained twice, at baseline and after 3-year follow-up, from 25 patients with probable Alzheimer's disease (AD). Levels of sAbeta and apoE from patients with the apoE4 allele decreased with time, whereas the levels were similar in patients without apoE4 allele. Changes of sAbeta and apoE concentrations correlated significantly with those of mini-mental state examination (MMSE) scores. Levels of sAbeta did not change with time in patients with mild dementia, whereas they decreased significantly in patients with moderate dementia. ApoE concentrations decreased in both groups whereas APP levels were similar. We conclude that measurements of CSF sAbeta and apoE levels may be helpful in monitoring progression of the disease.

Free light chains in multiple sclerosis urine

We measured free kappa (kappa) and lambda (lambda) light chains in urine from patients with definite multiple sclerosis (MS), other neurologic diseases (OND), and normal controls by using an enzyme linked immunosorbent assay. Both kappa and lambda light chains were higher in MS than OND or controls. In seven of eight relapsing-remitting (R-R) MS patients serial studies showed that urinary kappa chains were elevated during periods of worsening, and decreased during clinical recovery. In contrast, the levels of kappa chains did not correlate with clinical activity in 10 progressive (P) MS patients. Further correlation of urinary light chains with neurologic evaluations in R-R and P MS patients over a longer period are needed to determine their clinical and biological relevance.

Increased plasma amyloid beta protein 1-42 levels in Down syndrome

Amyloid beta protein 1-40 (A beta40) and A beta42 levels were quantitated in plasma from 43 persons with Down syndrome (DS; 26-68 years of age), 43 age-matched normal controls, and 19 non-DS mentally retarded (MR) persons (26-91 years of age) by using a sandwich enzyme linked immunosorbent assay. A beta40 levels were higher in DS and MR than controls, but were similar between DS and MR groups. A beta42 levels were higher in DS than controls or MR persons. The ratios of A beta42/A beta40 were higher in DS than controls or MR persons. The findings are consistent with those seen in DS brains.

Intrathecal production of measles-specific IgA in subacute sclerosing panencephalitis

OBJECTIVE

We measured measles-specific IgA in matched pairs of cerebrospinal fluid (CSF) and sera of patients with subacute sclerosing panencephalitis (SSPE), multiple sclerosis (MS), other central nervous system (CNS) infectious diseases (INF) and other neurological diseases (OND) by using enzyme linked immunosorbent assay.

MATERIALS AND METHODS

CSF and sera from 23 patients with SSPE, 15 with MS, 14 with INF, and 15 with OND were included in the study.

RESULTS

The ratios of measles-specific IgA in CSF to serum were increased in SSPE patients compared to patients with MS, INF or OND.

CONCLUSION

The data indicate a local production of measles-specific IgA in the CNS of SSPE patients.

Leukocytes in neuronal ceroid-lipofuscinoses: function and apoptosis

The neuronal ceroid-lipofuscinoses (NCL) are a group of progressive encephalopathies with a fatal course that are mostly of autosomal recessive inheritance. The pathophysiological mechanisms causing the diseases are not known. The characteristic histomorphological feature of the NCL is an abnormal lysosomal accumulation of lipopigments in neural and extraneural cells, including peripheral blood leukocytes. We studied the function of peripheral venous blood immunocompetent cells in ten patients with NCL and in age- and sex-matched controls to determine how, if at all, the accumulation of intracytoplasmic storage material influences the functional capacity of affected tissue. Our results did not reveal any functional impairment of affected cells, but rather suggested a higher turnover rate in NCL. Apoptosis was increased, suggesting that abnormally controlled programmed cell death might play an important role in the pathogenesis of NCL.

Increased levels of interleukin-1beta and soluble intercellular adhesion molecule-1 in cerebrospinal fluid of patients with subacute sclerosing panencephalitis

Proinflammatory cytokines (interleukin [IL]-1beta, tumor necrosis factor [TNF]-alpha, and IL-6) and soluble intercellular adhesion molecule-1 (sICAM-1) were measured in paired cerebrospinal fluid (CSF) and serum samples from patients with subacute sclerosing panencephalitis (SSPE), multiple sclerosis (MS), or other neurologic diseases (OND) by ELISA. IL-1beta was significantly increased in CSF of the SSPE group compared with levels in the MS or OND group. IL-1beta CSF/serum ratios were higher in the SSPE than in the MS or OND group. TNF-alpha and IL-6 levels were similar in the 3 groups. CSF sICAM-1 was higher in the SSPE group than in the MS or OND group. sICAM-1 CSF/serum ratios were higher in the SSPE than the OND group. The increased CSF/serum ratios of IL-1beta and sICAM-1 in SSPE indicate synthesis of IL-1beta and sICAM-1 in the central nervous system and may be important in the pathogenesis of disease.

Apolipoprotein E genotype and amyloid load in Alzheimer disease and control brains

We investigated the effect of apolipoprotein E (apoE) genotype on amyloid load in the frontal and cerebellar cortices of 24 patients with definite Alzheimer disease (AD) and 19 controls. Amyloid load was examined by using two methods: 1) acid-extractable amyloid beta-protein (A beta) and insoluble A beta levels of frontal and cerebellar cortices were measured by using enzyme-linked immunosorbent assay, and 2) all types of amyloid plaques and neurofibrillary tangles (NFT) in the frontal cortices were counted after silver staining. Acid-extractable A beta and insoluble A beta levels were higher in AD brains than controls, although there was an overlap between the groups. Acid-extractable A beta and insoluble A beta levels were higher from AD and controls with the apoE epsilon 4 alleles than those without such alleles. However, the differences did not reach statistical significance in AD group. There was no correlation between acid-extractable A beta or insoluble A3 levels and the number of amyloid plaques in AD and control brains. However, insoluble A beta levels correlated positively with the number of NFT in AD brains. Our results show that although apoE epsilon 4 influences the accumulation of A beta, multiple processes may be involved in deposition of A beta in the brain.

Apolipoprotein E (apoE) levels in brains from Alzheimer disease patients and controls

We measured apolipoprotein E (apoE) level in neutral and acidic pH extracts of the frontal, temporal and cerebellar cortices from patients with definite Alzheimer's disease (AD) and controls, and analyzed the relationship among apoE levels, clinical and neuropathological findings, and apoE genotype. Our data showed that the levels varied in different brain regions being lowest in the frontal cortex and highest in the cerebellum in Ad brains. ApoE levels in neutral pH extracts from the frontal cortex from AD patients were significantly lower than those of controls, and correlated negatively with the number of neurofibrillary tangles. ApoE genotype was not associated with the levels of apoE. There was no correlation between apoE levels and amyloid load or synaptophysin-immunoreactivity in the brain. We conclude that apoE levels are not increased in AD brains. However, apoE levels vary in different brain regions, and local factors related to the synthesis and metabolism of apoE may be crucial in the pathogenesis of AD.

Cerebrospinal fluid concentrations of soluble amyloid beta-protein and apolipoprotein E in patients with Alzheimer's disease: correlations with amyloid load in the brain

OBJECTIVE

To compare soluble amyloid beta-protein and apolipoprotein E levels in cerebrospinal fluid (CSF) and brain extracts from patients with definite Alzheimer's disease.

SETTING

University medical center.

PATIENTS

Nineteen patients with definite Alzheimer's disease.

MAIN OUTCOME MEASURES

Soluble amyloid beta-protein and apolipoprotein E levels in CSF, in neutral and low-pH brain extracts, and in formic acid-treated sections of the frontal, temporal, and cerebellar cortices, measured using enzyme-linked immunosorbent assay.

RESULTS

Soluble amyloid beta-protein and apolipoprotein E levels in CSF were significantly lower in patients with congophilic angiopathy than in those without angiopathy. The levels did not correlate with the number of amyloid plaques in the neocortex. There was, however, a tendency toward an inverse correlation between the amount of amyloid beta-protein in the frontal cortex extracts and the soluble amyloid beta-protein level in CSF.

CONCLUSION

Soluble amyloid beta-protein levels in CSF may reflect amyloid accumulation in brain blood vessels.

Apolipoprotein E (apoE) polymorphism and its influence on ApoE concentrations in the cerebrospinal fluid in Finnish patients with Alzheimer's disease

The apoE phenotype of 83 patients with probable Alzheimer's disease (AD) and of 164 non-demented controls was determined by isoelectric focusing and Western blotting. The proportion of the epsilon 4 allele was 0.548 in AD and 0.202 in controls (P < 0.0001). The effect was seen in both early-onset and late-onset AD patients. The risk of AD in epsilon 4 homozygotes was 18-fold greater than in individuals without the epsilon 4 allele. ApoE concentrations were measured in serum and cerebrospinal fluid (CSF) from a subgroup of patients with AD (n = 72) and controls (n = 84) by a sandwich enzyme-linked immunosorbent assay. Although serum apoE concentrations were lower in individuals with the epsilon 4 allele than in those without the epsilon 4 allele, CSF apoE concentrations did not vary in different phenotype groups. However, CSF apoE levels were lower in AD patients than in controls. We conclude that the inheritance of the epsilon 4 allele of apoE is a risk factor for AD in the Finnish population.

Soluble amyloid beta-protein in the cerebrospinal fluid from patients with Alzheimer's disease, vascular dementia and controls

Cerebrospinal fluid (CSF) soluble amyloid beta-protein (sA beta) concentrations from 69 patients with Alzheimer's disease (AD), 23 patients with vascular dementia (VD), and 76 non-demented controls were measured by a sandwich enzyme linked immunosorbent assay using two monoclonal antibodies (4G8 and 6E10) specific for A beta. sA beta concentrations were lower in CSF from patients with AD or VD compared to those in controls. CSF sA beta concentrations did not correlate with the Mini-Mental State Examination scores in patients with AD. VD patients with moderate to severe dementia had lower CSF sA beta concentrations than those with mild dementia. Because a considerable overlap of CSF sA beta levels existed between AD and control groups, the assay is not useful as a diagnostic test for AD.

Interaction of scrapie agent and cells of the lymphoreticular system

The current study focused on the role of lymphoid elements of the lymphoreticular system in scrapie pathogenesis. In the first experiment, adherent and non-adherent splenocytes from mice infected with the 139A scrapie strain were prepared. The level of infectivity on a per cell basis was significantly higher in the adherent cell population. In a second set of experiments, thymocytes, unfractionated splenocytes, T-cell enriched and T-cell depleted fractions of splenocytes were infected in vitro with ME7 scrapie strain. There was no evidence of replication of scrapie in ME7-exposed cells in any of the preparations during the first 5-14 days post-exposure. In assays done 5 days after infection, most of the infectivity was cell-associated. These data suggest that lymphoid cells are not involved in scrapie replication. The level of IgA in the serum of 139A-infected mice was markedly reduced compared to the levels in mice injected with normal mouse brain homogenate or with the ME7 scrapie strain. The reduction in IgA levels in 139A-infected mice was evident at each of the 4 time points tested. The final experiment dealt with the question of scrapie replication in the lymphoreticular organs in mouse strains with different incubation periods for 139A after intraperitoneal injection. The results in this experiment suggest that the difference in incubation periods is related to differences in time of access of infection to the central nervous system rather than to differences in the ability of agent to replicate in spleen.

Alpha 1-antichymotrypsin and IL-1 beta are not increased in CSF or serum in Alzheimer's disease

Chronic inflammation associated with the amyloid plaques may represent an acute phase response in the brain. We quantitated the levels of two inflammatory markers; alpha 1-antichymotrypsin (alpha 1-ACT) and interleukin 1 beta (IL-1 beta) in paired serum and cerebrospinal fluid (CSF) samples from 40 patients with Alzheimer's disease (AD), 20 patients with Parkinson's disease (PD), and 42 age-matched controls. No differences in serum or CSF levels of either alpha 1-ACT or IL-1 beta were found between the groups. However, some AD patients had increased alpha 1-ACT index, suggesting an intrathecal production of alpha 1-ACT. Although alpha 1-ACT or IL-1 beta might be involved in the pathogenesis of AD, our results show that their measurement in serum or CSF is not valuable to support the clinical diagnosis of AD.

Urinary free kappa light chain levels in chronic progressive multiple sclerosis

Previous studies have shown elevated levels of free kappa light chains (FKLC) in the urine of patients with relapsing-remitting multiple sclerosis (MS). The levels correlated well with clinical relapses, indicating that they could serve as useful markers of disease activity. In this study, we performed monthly measurements of urinary FKLC in patients with the chronic progressive form of MS, and correlated them with clinical indicators of disease activity, as expressed by Kurtzke's expanded disability status scale (EDSS) and brain magnetic resonance imaging (MRI). We noted wide fluctuations in the FKLC levels, which correlated poorly with EDSS scores or MRI changes. Longer follow-up periods may be needed before definite conclusions can be drawn.

Immunoglobulin G subclasses in older persons with Down syndrome

IgG subclasses were measured in sera from 33 persons with Down syndrome (DS) (mean age 55 +/- 7 years) and 33 age- and sex-matched control individuals using a mouse monoclonal antibody based sandwich enzyme linked immunosorbent assay. Significantly higher levels of IgG1 and IgG3 and lower levels of IgG2 and IgG4 subclasses were found in the DS group compared to the control individuals. The higher levels of IgG1 and IgG3 subclasses found in DS persons were consistent with those seen in patients with autoimmune diseases and chronic viral infections; the lower levels of IgG2 and IgG4 subclasses were consistent with those seen in patients with recurrent infections. Our findings are similar to those reported in children with DS. We speculate that the subclass levels may have little or no relationship to the development of brain lesions typical of Alzheimer disease in older persons with DS. There were no significant differences between the levels of IgG subclasses of persons with DS showing signs of dementia of the Alzheimer type compared to those without such manifestations.

Increased levels of beta 2-microglobulin, soluble interleukin-2 receptor, and soluble CD8 in patients with subacute sclerosing panencephalitis

We measured beta 2-microglobulin (beta 2-M), soluble interleukin-2 receptor (sIL-2R), and soluble CD8 (sCD8) antigen levels in paired cerebrospinal fluid (CSF) and sera from patients with subacute sclerosing panencephalitis (SSPE), multiple sclerosis (MS), and other neurological diseases (OND) using enzyme-linked immunosorbent assay. beta 2-M was significantly increased in CSF of the SSPE group compared to the MS or the OND group. Similarly, beta 2-M in the MS versus OND group was significantly increased in CSF. Although serum levels of beta 2-M were similar in the three groups, the CSF/serum ratios were higher in SSPE versus the MS group and in the MS versus the OND group. Levels of sIL-2R and sCD8 were higher in SSPE CSF than OND CSF; however, there were no differences between levels in SSPE and MS CSF. The levels of sIL-2R were increased in SSPE sera compared to those of MS or the OND group, whereas levels of sCD8 in serum from the three groups were similar. The findings of increased CSF/serum ratio of beta 2-M and higher levels of serum sIL-2R and CSF sCD8 in SSPE patients are consistent with those seen in patients with acute and chronic viral infections. When the levels between the initial and follow-up CSF and serum samples from SSPE patients were compared, the data showed that CSF levels of sCD8 elevated during periods of clinical worsening and decreased during clinical improvement. In contrast, serum beta 2-M decreased during periods of worsening and increased during improvement. The measurement of serum beta 2-M and CSF sCD8 may be useful in SSPE patients as markers to monitor disease activity.