Blood-cerebrospinal fluid (CSF) barrier dysfunction means reduced CSF flow not barrier leakage - conclusions from CSF protein data

BACKGROUND

Increased concentrations of serum proteins in cerebrospinal fluid (CSF) are interpreted as blood-CSF barrier dysfunction. Frequently used interpretations such as barrier leakage, disruption or breakdown contradict CSF protein data, which suggest a reduced CSF flow rate as the cause.

RESULTS

Even the severest barrier dysfunctions do not change the molecular size-dependent selectivity or the interindividual variation of the protein transfer across barriers. Serum protein concentrations in lumbar CSF increase with hyperbolic functions, but the levels of proteins that do not pass the barrier remain constant (brain proteins) or increase linearly (leptomeningal proteins). All CSF protein dynamics above and below a lumbar blockade can also be explained, independent of their barrier passage, by a reduced caudally directed flow. Local accumulation of gadolinium in multiple sclerosis (MS) is now understood as due to reduced bulk flow elimination by interstitial fluid (ISF). Nonlinear change of the steady state in barrier dysfunction and along normal rostro-caudal gradients supports the diffusion/flow model and contradicts obstructions of diffusion pathways. Regardless of the cause of the disease, pathophysiological flow blockages are found in bacterial meningitis, leukemia, meningeal carcinomatosis, Guillain-Barré syndrome, MS and experimental allergic encephalomyelitis. In humans, the fortyfold higher albumin concentrations in early fetal development decrease later with maturation of the arachnoid villi, i.e., with beginning CSF outflow, which contradicts a relevant outflow to the lymphatic system. Respiration- and heartbeat-dependent oscillations do not disturb net direction of CSF flow.

CONCLUSION

Blood-CSF and blood-brain barrier dysfunctions are an expression of reduced CSF or ISF flow rate.

Free light chain kappa and the polyspecific immune response in MS and CIS - Application of the hyperbolic reference range for most reliable data interpretation

OBJECTIVES

Free light chain kappa (FLC-k) in cerebrospinal fluid (CSF) is involved in intrathecal immune responses and is being investigated frequently for its diagnostic sensitivity. The objective of this study was the application and interpretation of FLC-k data in quotient diagrams with a hyperbolic reference range and to confirm the superior evaluation in comparison with another proposed reference method and cut-off values. Secondly, the performance of the FLC-k quotient diagram was analyzed in respect to MS and CIS patients and in relation to the polyspecific immune response.

MATERIALS AND METHODS

FLC-k was analyzed in a control cohort (n = 302) and in patients with MS/CIS (n = 98) using a nephelometric FLC-k kit. The intrathecal fraction of FLC-k based on the hyperbolic reference range was calculated in comparison to various linear FLC-k indices and routine CSF parameters [oligoclonal bands (OCB), polyspecific antiviral immune response].

RESULTS

Using the new hyperbolic reference range, intrathecal FLC-k synthesis was found in 20 / 302 OCB negative controls. The sensitivity in the definitive MS cohort was 100%, compared to 93% positive OCB. The linear FLC-k Index interpretation with similar sensitivity for MS, however, bares the risk for the control samples,depending on the reference range, of false positive interpretations (up to 7 at low QAlb) or false negative interpretations (up to 17/20 FLC-k positives at high QAlb). The quantitative mean intrathecal FLC-k synthesis in the CIS cohort (later MS) was even slightly higher than in initially definitive MS questioning a pathophysiological difference. A positive MRZ reaction found in 53% percent of CIS patients with intrathecal FLC-k synthesis could have allowed diagnosis of MS immediately, i.e. earlier than with the Mc Donald criteria.

CONCLUSIONS

The evaluation of FLC-k with hyperbolic reference range in quotient diagrams is superior to other analytical methods like the linear FLC-k index. We suggest a sequential CSF testing with FLC-k Reibergram evaluation, potentially followed by isoelectric focusing. With the MRZ reaction we obtain highest specificity for MS diagnosis.

Diagnostic relevance of free light chains in cerebrospinal fluid - The hyperbolic reference range for reliable data interpretation in quotient diagrams

BACKGROUND

Free light chains, type kappa (FLC-K), in cerebrospinal fluid (CSF) were compared to oligoclonal IgG in many studies for sensitive detection of immune reactions in brain. The missing consensus about CSF data interpretation prevents reliable conclusions. This can be overcome by a theory-based hyperbolic reference range in CSF/serum quotient diagrams.

METHODS

Mean Quotients for FLC-K, Q_Kappa, and albumin, QAlb, of grouped, biochemically defined controls (N = 433) are fitted with the hyperbolic function Q_Kappa(mean) = a/b (QAlb² + b²)^0.5 - c by a generally applicable procedure excluding outliers.

RESULTS

With Q_Kappa(mean), the coefficient of variation CV (22.5%) and the reference range (Q_Kappa(mean) ± 3 CV) we got the discrimination line Q_Kappa(lim) = (3.27(QAlb² + 33)^0.5-8.2) ×10^-3 in a FLC-K Reibergram. Intrathecal FLC-K was found in 8% of another control group without OCB (N = 388) but was missed in 7% of patients with definite Multiple sclerosis (N = 95). In MS the mean intrathecal fraction was threefold larger for FLC-K (95%) compared to total IgG (36%). Similar mean quantities of intrathecal FLC-K contradict an immunological conversion between a Clinically isolated syndrome and MS.

DISCUSSION

The hyperbolic reference range is superior to linear FLC-K Index (10 to 15% false negatives) and exponential curves (30% false positive interpretations for controls) in the analytical range of MS data, with excellent data fit for up to ten-fold larger QAlb values. Dynamics of the small molecule FLC-K contribute to the understanding of molecular size dependent barrier functions.

Polyspecific antibodies without persisting antigen in multiple sclerosis, neurolupus and Guillain-Barré syndrome: immune network connectivity in chronic diseases

The polyspecific antibody synthesis in multiple sclerosis (MS) gained diagnostic relevance with the frequent combination of measles-, rubella- and varicella zoster antibodies (MRZ-antibody reaction) but their pathophysiological role remains unknown. This review connects the data for intrathecal polyspecific antibody synthesis in MS and neurolupus with observations in the blood of patients with Guillain-Barré syndrome (GBS). Simultaneously increased antibody and autoantibody titers in GBS blood samples indicate that the polyspecific antibodies are based on a general property of an immune network, supported by the deterministic day-to-day concentration variation of antibodies in normal blood. Strongly correlated measles- and rubella- antibody variations point to a particular connectivity between the MRZ antibodies. The immune network, which provides serological memory in the absence of an antigen, implements the continuous change of the MRZ pattern in blood, not followed by the earlier immigrated B cells without corresponding connectivity in the brain. This may explain the different antibody patterns in cerebrospinal fluid, aqueous humor and blood of the individual MS patient. A complexity approach must implement a different view on causation in chronic diseases and causal therapies.

Knowledge-base for interpretation of cerebrospinal fluid data patterns. Essentials in neurology and psychiatry

The physiological and biophysical knowledge base for interpretations of cerebrospinal fluid (CSF) data and reference ranges are essential for the clinical pathologist and neurochemist. With the popular description of the CSF flow dependent barrier function, the dynamics and concentration gradients of blood-derived, brain-derived and leptomeningeal proteins in CSF or the specificity-independent functions of B-lymphocytes in brain also the neurologist, psychiatrist, neurosurgeon as well as the neuropharmacologist may find essentials for diagnosis, research or development of therapies. This review may help to replace the outdated ideas like "leakage" models of the barriers, linear immunoglobulin Index Interpretations or CSF electrophoresis. Calculations, Interpretations and analytical pitfalls are described for albumin quotients, quantitation of immunoglobulin synthesis in Reibergrams, oligoclonal IgG, IgM analysis, the polyspecific ( MRZ- ) antibody reaction, the statistical treatment of CSF data and general quality assessment in the CSF laboratory. The diagnostic relevance is documented in an accompaning review.

Cerebrospinal fluid data compilation and knowledge-based interpretation of bacterial, viral, parasitic, oncological, chronic inflammatory and demyelinating diseases. Diagnostic patterns not to be missed in neurology and psychiatry

The analysis of intrathecal IgG, IgA and IgM synthesis in cerebrospinal fluid (CSF) and evaluation in combined quotient diagrams provides disease-related patterns. The compilation with complementary parameters (barrier function, i.e., CSF flow rate, cytology, lactate, antibodies) in a cumulative CSF data report allows a knowledge-based interpretation and provides analytical and medical plausibility for the quality assessment in CSF laboratories. The diagnostic relevance is described for neurological and psychiatric diseases, for which CSF analysis can't be replaced by other diagnostic methods without loss of information. Dominance of intrathecal IgM, IgA or three class immune responses give a systematic approach for Facial nerve palsy, Neurotrypanosomiasis, Opportunistic diseases, lymphoma, Neurotuberculosis, Adrenoleucodystrophy or tumor metastases. Particular applications consider the diagnostic power of the polyspecific antibody response (MRZ-antibodies) in multiple sclerosis, a CSF-related systematic view on differential diagnostic of psychiatric diseases and the dynamics of brain- derived compared to blood-derived molecules in CSF for localization of paracytes.

Cerebrospinal fluid neopterin is brain-derived and not associated with blood-CSF barrier dysfunction in non-inflammatory affective and schizophrenic spectrum disorders

Many psychiatric patients have a minor blood-CSF barrier dysfunction and increased Cerebrospinal fluid (CSF) neopterin concentrations. The source of normal CSF neopterin, a biomarker in inflammatory and non-inflammatory neurological diseases, has never been shown explicitly, a precondition for sensitive detection of pathologically increased CSF neopterin. Neopterin concentrations (ELISA) in CSF and serum of normal controls (n = 26) are evaluated by inter-individual variation propagation. Normal CSF neopterin is brain-derived: The inter-individual variation of CSF neopterin in the control group does not depend on serum neopterin concentration variation (coefficient of variation, CV-CSF = 9.7% < CV-serum = 24.5%). Additionally individual normal CSF neopterin concentrations are invariant to the variation of the albumin quotient, QAlb, i.e. CSF neopterin does not derive from leptomeninges. Subsequently CSF neopterin was interpreted with reference to its absolute concentration in CSF (cut off = 5.5 nmol/l). Patients (N = 44), retrospectively selected from a larger group with schizophrenic and affective spectrum disorder, are characterized by the absence of any clinical and neurochemical signs of inflammation. In this group 30% had an increased CSF neopterin concentration and 30% had an increased QAlb with only 7% combined pathologies. Increased CSF neopterin did not correlate with the blood-CSF barrier dysfunction. In the discussion we point to possible sources of both independent pathologies, connected either with reduced CSF flow rate (QAlb) or microglial activation (neopterin). With CSF neopterin analysis earlier in vitro studies about microglia activation in schizophrenic spectrum disorders or corresponding therapeutic efforts could get a more direct, in-vivo analytical tool.

Stage progression and neurological symptoms in Trypanosoma brucei rhodesiense sleeping sickness: role of the CNS inflammatory response

BACKGROUND

Human African trypanosomiasis progresses from an early (hemolymphatic) stage, through CNS invasion to the late (meningoencephalitic) stage. In experimental infections disease progression is associated with neuroinflammatory responses and neurological symptoms, but this concept requires evaluation in African trypanosomiasis patients, where correct diagnosis of the disease stage is of critical therapeutic importance.

METHODOLOGY/PRINCIPAL FINDINGS

This was a retrospective study on a cohort of 115 T.b.rhodesiense HAT patients recruited in Eastern Uganda. Paired plasma and CSF samples allowed the measurement of peripheral and CNS immunoglobulin and of CSF cytokine synthesis. Cytokine and immunoglobulin expression were evaluated in relation to disease duration, stage progression and neurological symptoms. Neurological symptoms were not related to stage progression (with the exception of moderate coma). Increases in CNS immunoglobulin, IL-10 and TNF-α synthesis were associated with stage progression and were mirrored by a reduction in TGF-β levels in the CSF. There were no significant associations between CNS immunoglobulin and cytokine production and neurological signs of disease with the exception of moderate coma cases. Within the study group we identified diagnostically early stage cases with no CSF pleocytosis but intrathecal immunoglobulin synthesis and diagnostically late stage cases with marginal CSF pleocytosis and no detectable trypanosomes in the CSF.

CONCLUSIONS

Our results demonstrate that there is not a direct linkage between stage progression, neurological signs of infection and neuroinflammatory responses in rhodesiense HAT. Neurological signs are observed in both early and late stages, and while intrathecal immunoglobulin synthesis is associated with neurological signs, these are also observed in cases lacking a CNS inflammatory response. While there is an increase in inflammatory cytokine production with stage progression, this is paralleled by increases in CSF IL-10. As stage diagnostics, the CSF immunoglobulins and cytokines studied do not have sufficient sensitivity to be of clinical value.

Mannan-binding lectin in cerebrospinal fluid: a leptomeningeal protein

BACKGROUND

Mannan-binding lectin (MBL), a protein of the innate immune response is attracting increasing clinical interest, in particularly in relation to its deficiency. Due to its involvement in brain diseases, identifying the source of MBL in CSF is important. Analysis of cerebrospinal fluid (CSF) can provide data that discriminates between blood-, brain-, and leptomeninges-derived proteins. To detect the source of MBL in CSF we need to consider three variables: the molecular size-dependent concentration gradient between CSF and blood, the variation in transfer between blood and CSF, and the CSF MBL concentration correlation with the albumin CSF/serum quotient (QAlb), i.e., with CSF flow rate.

METHODS

MBL was assayed in samples of CSF and serum with an ELISA, coated with anti MBL antibodies. Routine parameters such as albumin-, immunoglobulin- CSF/serum quotients, oligoclonal IgG and cell count were used to characterize the patient groups. Groups comprised firstly, control patients without organic brain disease with normal CSF and normal barrier function and secondly, patients without inflammatory diseases but with increased QAlb, i.e. with a blood CSF barrier dysfunction.

RESULTS

MBL concentration in CSF was at least five-fold higher than expected for a molecular-size-dependent passage from blood. Secondly, in a QIgM/QAlb quotient diagram (Reibergram) 9/13 cases showed an intrathecal fraction in some cases over 80% of total CSF MBL concentration 3) The smaller inter-individual variation of MBL concentrations in CSF of the control group (CV = 66%) compared to the MBL concentrations in serum (CV = 146%) indicate an independent source of MBL in CSF. 4) The absolute MBL concentration in CSF increases with increasing QAlb. Among brain-derived proteins in CSF only the leptomeningeal proteins showed a (linear) increase with decreasing CSF flow rate, neuronal and glial proteins are invariant to changes of QAlb.

CONCLUSIONS

MBL in CSF is predominantly brain-derived and all results pointed to the leptomeningeal cells as the source of the protein. The evaluation of this protein requires the interpretation of its absolute concentrations in CSF as a function of the albumin quotient, QAlb. This recognition of MBL in brain cells opens a new field of discussion about the function of the innate immune response in CNS in cases of acute and chronic neurological diseases.

Mannose-binding lectin deficiency with eosinophilic meningoencephalitis due to Angiostrongylus cantonensis in children: a case series

INTRODUCTION

Eosinophilic meningitis, a potentially fatal disease caused by Angiostrongylus cantonensis, is considered an emerging infectious disease.

CASE PRESENTATION

Three Caucasian boys (aged five-years-old, 10-years-old and six-years-old) with a diagnosis of eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis were studied. Serum immunoglobulin A (IgA), IgM, IgG, and complements C3c and C4 levels were quantified by using an immunodiffusion technique. Immunoglobulin E in serum was quantified by nephelometry and mannose-binding lectin by time-resolved fluorometry. Mannose-binding lectin deficiency was observed in the three patients. The first patient showed a reduction in the levels of IgA and IgM and an increase in the values of IgE and C4. The second patient showed a reduction in mannose-binding lectin level with increased IgG, C4 and IgE levels, and the third patient showed a decrease in mannose-binding lectin level and increased levels of IgM and complement C3c as well as a low level of C4.

CONCLUSIONS

To the best of our knowledge, this is the first report of mannose-binding lectin deficiency associated with Angiostrongylus cantonensis meningoencephalitis in children, and it may contribute to the understanding of the participation of this component of the lectin pathway in the development of the disease.

Intrathecal IgM synthesis in pediatric MS is not a negative prognostic marker of disease progression: quantitative versus qualitative IgM analysis

Background: Intrathecal IgM synthesis is reported to be associated with a worse prognosis in adults with multiple sclerosis (MS).

Objective: To study the predictive value of intrathecal IgM synthesis for the clinical course of pediatric MS.

Methods: Seventy children with onset of MS before the age of 16 years and followed for a median period of 10.4 years (range: 0.4–22.8 years) were studied. The two subgroups with ( n = 44) or without ( n = 26) intrathecal IgM synthesis were distinguished by a new, very sensitive, evaluation of quantitative analysis in cerebrospinal fluid (CSF)/serum quotient diagrams (Reibergrams). The clinical course and EDSS (Expanded Disability Status Scale) scores at five and ten years were compared with IgM frequencies between both groups with a new statistics program for CSF data.

Results: The cohort of children without intrathecal IgM production had higher numbers of attacks in the first two years and shorter time intervals between first and second attack, although this was not statistically significant ( p = 0.04, p = 0.15 respectively). In addition there was also a trend for girls without intrathecal IgM synthesis to have a higher EDSS score after 10 years compared with the group with IgM synthesis.

Conclusion: Intrathecal IgM synthesis is not associated with a more rapid progression of disability in pediatric MS. Reevaluation of data from previous reports about the negative predictive value of intrathecal IgM synthesis in adult MS with a CSF statistics tool show that the apparent contradiction is due to a methodological bias in the qualitative detection of ‘oligoclonal’ IgM or linear IgM index.

Paediatric and adult multiple sclerosis: age-related differences and time course of the neuroimmunological response in cerebrospinal fluid

We investigate common pathophysiology in paediatric and adult multiple sclerosis (MS) by comparison of cerebrospinal fluid (CSF) data. We compared cerebrospinal fluid (CSF) data from eight patient groups with onset of MS at 7 to 29 years (n = 184). A new statistics program allows sensitive detection, quantifies the mean amount of intrathecal Ig synthesis in groups based on the 96% reference range of 4100 non-inflammatory controls, corrects for age-related increase of blood-derived albumin and immunoglobulins in CSF, and presents graphical data interpretation in Reibergrams. Already at onset of MS before puberty (< or =10 years) the frequency of intrathecal IgG synthesis (oligoclonal IgG) was 100% like in adults with 98%, but the amount of intrathecal IgG increases twofold during puberty. Intrathecal IgM synthesis is most frequent before and during puberty (in 57-67% of patients) compared with 41% in adults. The amount of intrathecal IgM synthesis before puberty is only 30% of that in adults. IgG and IgM Index are biased evaluations not suitable for characterizing age-related dynamics. A twofold age-related increase of the albumin quotient, Q(Alb), as a measure of the blood-CSF barrier function, represents normal physiological growth. Cell counts in CSF are low. The pre-puberty gender ratio is about 1:1. Intrathecal antibodies against measles, rubella and/or varicella zoster virus are detected in 73% of patients before puberty compared with 89% of adults. Individual paediatric patients (n = 17), with sequential punctures over 2-5 years, show constant quantities of intrathecal IgM and specific antibodies. In conclusion, paediatric MS already at first clinical manifestation shows the complete, neuroimmunological data pattern in CSF, i.e. inflammatory signs are not gradually evolving. Paediatric and adult MS differ quantitatively but not qualitatively in neuroimmunological patterns which does not allow for discrimination between 'early' and 'late' onset MS. CSF analysis may help to discriminate between acute and mono-symptomatic chronic inflammatory disease already at earliest clinical manifestation.

Treatment failure related to intrathecal immunoglobulin M (IgM) synthesis, cerebrospinal fluid IgM, and interleukin-10 in patients with hemolymphatic-stage sleeping sickness

Human African trypanosomiasis treatment is stage dependent, but the tests used for staging are controversial. Central nervous system involvement and its relationship with suramin treatment failure were assessed in 60 patients with parasitologically confirmed hemolymphatic-stage Trypanosoma brucei gambiense infection (white blood cell count of or=1.9 mg/liter (OR, 11.7; 95% CI, 2.7 to 50), a CSF end titer by the LATEX/IgM assay of >or=2 (OR, 10.4; 95% CI, 2.5 to 44), and a CSF interleukin-10 concentration of >10 pg/ml (OR, 5; 95% CI, 1.3 to 20). The sensitivities of these markers for treatment failure ranged from 43 to 79%, and the specificities ranged from 74 to 93%. The results show that T. brucei gambiense-infected patients who have signs of neuroinflammation in CSF and who are treated with drugs recommended for use at the hemolymphatic stage are at risk of treatment failure. This highlights the need for the development and the evaluation of accurate point-of-care tests for the staging of human African trypanosomiasis.

Quantitation of intrathecal antibodies in cerebrospinal fluid of subacute sclerosing panencephalitis, herpes simplex encephalitis and multiple sclerosis: discrimination between microorganism-driven and polyspecific immune response

The detection of intrathecal antibody synthesis by qualitative methods or the Antibody-Index (AI) is a relevant tool for diagnosis of inflammatory neurological diseases. An increased AI can be observed for a causative antigen as well as part of a polyspecific immune response. The quantitation of the intrathecal antibody fraction in cerebrospinal fluid (CSF), F(S), helps to discriminate both cases. In contrast to AI, F(S) needs an absolute antibody concentration detected in the ELISA in mg/L. The intrathecally synthesized, "local" antibody concentration in CSF (AB(Loc)) is expressed as the specific fraction of the intrathecally synthesized total IgG (IgG(Loc)) in CSF with F(S)=AB(Loc)/IgG(Loc) x 100 in %. F(S) for HSV or measles has about 20- to 60-fold higher values in virus-caused antibody synthesis in acute herpes simplex encephalitis (mean HSV-F(S)=8.9%) or subacute sclerosing panencephalitis (mean measles-F(S)=18.8%) compared to the polyspecific immune response against these antigens e.g., in multiple sclerosis (0.14% or 0.52%, correspondingly). F(S) helps also to avoid misinterpretations of an increasing AI in cases of therapy control, and allows direct comparison of relative antibody concentrations (R(S)) in blood and intrathecally synthesized fractions in CSF (F(S)): In multiple sclerosis patients F(S):R(S) has a mean ratio of about 3 for the measles, rubella and VZV antibodies. Together with the large variability we find by ranking that about two third of MS patients have no direct correlation of the relative concentrations in serum and intrathecal synthesis. So this concept gains increasingly relevance for analysis of the polyspecific immune response in brain.

Intrathecal polyspecific immune response to neurotropic viruses in multiple sclerosis: a comparative report from Cuban patients

OBJECTIVE

Intrathecal measles(M)- rubella(R)- and varicella zoster(Z)-antibody synthesis in German and Cuban multiple sclerosis (MS) patients are compared considering the different rubella epidemiology in the tropics.

PATIENTS AND METHODS

Twenty-three Cuban MS patients with a representative age distribution and gender ratio like the group of 177 German MS patients were analysed for albumin, IgG, IgA IgM, oligoclonal IgG and MRZ- antibodies in cerebrospinal fluid (CSF) and serum.

RESULTS

Cuban MS patients show similar CSF data patterns like German patients and high frequencies of intrathecal measles- (78/78%) and varicella zoster- (59/55%) antibody synthesis correspondingly. A lower frequency of intrathecal rubella antibody synthesis (rubella-AI >or= 1.5) in Cuban patients (30%, gender ratio of increased rubella - AI m:f = 1:6) compared with German patients (60%, m:f = 1:1.8) is explained by low incidence of rubella infections in Cuba. Only about 10% of the male population (not immunized before 1986, in contrast to females) had rubella antibodies compared to at least 60% in a European male population, representing the relation of increased rubella-AI in male MS patients.

CONCLUSION

In MS the frequency of intrathecal antibody synthesis is limited by the fraction of seropositives in the population. Natural infection or vaccination are a necessary and equivalent precondition contributing to the arguments against microorganisms as a cause of MS.

Immunoglobulins and virus-specific antibodies in patients with Creutzfeldt-Jakob disease

OBJECTIVES

Cerebrospinal fluid (CSF) pattern in patients with neuropathologically diagnosed Creutzfeldt-Jakob disease was analyzed.

MATERIAL AND METHODS

Routine tests included white blood cells count, protein, albumin, immunoglobulins and the presence of oligoclonal immunoglobulin G (IgG) in the CSF as well as the calculation of intrathecal synthesis of immunoglobulins by standard methods. In addition, antibodies against neurotropic viruses such as measles, rubella, varicella zoster and herpes simplex were measured and the specific antibody index was calculated.

RESULTS

A blood-CSF barrier dysfunction was observed in six of 25 cases. In CSF/serum quotient diagrams, no patient had intrathecally synthesized immunoglobulins, but in two of 25 patients oligoclonal bands were detected. Two patients had intrathecally synthesized antibodies against varicella zoster and three against herpes simplex virus.

CONCLUSION

In conclusion, in the routine diagnosis, the CSF in CJD is normal in most cases. In some patients, abnormalities include the blood-CSF barrier dysfunction, mild pleocytosis, oligoclonal bands and intrathecally synthesized viral antibodies.

CSF characteristics in early-onset multiple sclerosis

The authors studied CSF characteristics in 136 patients with multiple sclerosis (MS) with a disease onset before age 16. In the initial diagnostic lumbar puncture, CSF-pleocytosis was observed in 66%, blood-CSF barrier dysfunction in 13%, and oligoclonal IgG in 92% of the early-onset MS (EOMS) patients. CSF oligoclonal IgG supports the early diagnosis of MS in childhood with a sensitivity similar to adult-onset MS.

[Molecular diffusion/cerebrospinal fluid flow theory]

AIM

To review the fundamental aspects of the theory of the molecular flow/ cerebrospinal flux described recently and it can explained a group of events in the physiology of the cerebrospinal fluid and the physiopathology of neurological diseases.

DEVELOPMENT

This theory was based on the postulate that a decrease of the flux rate of the cerebrospinal fluid was accompanied by an increment of the protein concentration in it and in the nervous system tissue. The increment of the protein transport from the blood to the cerebrospinal fluid not require structural changes or an increase of permeability. The reibergram or Reiber's quotient diagram, with the discriminatory hyperbolic function with its theoretical basis and its clinical relevance confirm the acceptance of the present theory. This theory was based on the first and second Fick's diffusion laws The increment of the molecular diffusion is the cause of the non-linear decrease of the cerebrospinal flux rate because of the blood-cerebrospinal fluid barrier dysfunction.

CONCLUSIONS

This theory explain that an increase of the albumin quotient does not means a morphologic change on the barrier structures. The change in the cerebrospinal flux rate it has been considered the principal modulator of the protein concentration in cerebrospinal fluid in pathological conditions characterized by a blood-cerebrospinal fluid barrier dysfunction.

Fuchs heterochromic cyclitis: rubella virus antibodies and genome in aqueous humor

PURPOSE

To characterize the polyspecific intraocular antibody synthesis in aqueous humor of patients with chronic inflammatory diseases of the eye and to detect the causative antigen in Fuchs heterochromic cyclitis (FHC).

DESIGN

Retrospective case-control study.

METHODS

Intraocular antibody synthesis is detected in aqueous humor with the Antibody Index [AI] (improved Goldmann-Witmer Index) and quantified as specific antibody fraction, F(s) (intraocular specific antibody concentration in percent of intraocular total immunoglobulin G in aqueous humor). Virus detection is by nested polymerase chain reaction.

RESULTS

Fifty-two eyes of 52 patients with clinically defined FHC (aged 16-73 years) had an intraocular synthesis of rubella antibodies (AI > or =1.5). The rubella genome was detected in 5 (18%) of 28 aqueous humor samples investigated, or in 5 (56%) of 9 patients aged <40 years. Oligoclonal IgG was synthesized in 34 (87%) of 39 eyes. Unaffected fellow eyes (n = 3) or cerebrospinal fluid (n = 2) were normal. In FHC the median rubella AI = 20.6 (total range 1.5-309) was seven times higher than in multiple sclerosis (MS) patients (n = 15) with uveitis intermedia or periphlebitis retinae. In MS the intraocular rubella antibody synthesis (frequency 73%) is part of a polyspecific immune response (increased measles AI in 80%, varicella zoster virus AI in 47%, herpes simplex virus AI in 23%). The median rubella-F(s) = 2.6% in FHC (range = 0.14%-45.9%) was approximately 40 times higher than in MS, consistent with a virus-driven antibody response in FHC. Noninflammatory controls (50 senile cataracts) had neither an intraocular rubella antibody synthesis (normal AI < or =1.4) nor rubella antigen in aqueous humor. The rubella AI was normal in all patients with an intraocular toxoplasmosis (n = 24), anterior uveitis (n = 27), herpes simplex virus iritis (n = 25), and varicella zoster virus iritis (n = 14).

CONCLUSIONS

Fuchs heterochromic cyclitis is a rubella virus-driven disease with persistence of the virus preferentially detected in the younger patients. The proposed laboratory supported diagnosis of FHC is based on the increased rubella Antibody Index. The virus etiology gives a rationale for omitting the ineffective corticosteroid therapy of FHC.

Beta-trace protein as sensitive marker for CSF rhinorhea and CSF otorhea

OBJECTIVE

Beta-trace protein concentrations in cerebrospinal fluid (CSF), serum and nasal secretions are investigated with a new quantitative, immunonephelometric assay.

RESULTS

The mean beta-trace concentration of normal lumbar CSF (18.4 mg/l) and normal serum (0.59 mg/l), from n = 132 control patients, were 10% higher than reported earlier for smaller control groups. The reference range of beta-trace protein in nasal secretions is very low (median: 0.016 mg/l, range <0.003-0.12 mg/l, for n = 29 controls). Clinically confirmed cases of CSF rhinorhea (n = 20) showed beta-trace concentrations between 0.36 and 53.6 mg/l, with a median of 2.4 mg/l. We propose a cut-off value of 0.35 mg/l above which a CSF contamination in the secretion is plausible. A clinically confirmed CSF otorhea had a value of 1.75 mg/l.

CONCLUSION

This new beta-trace protein assay offers a fast, sensitive and reliable routine method to detect a CSF rhinorhea or otorhea.

Chlamydia pneumoniae in children with MS: frequency and quantity of intrathecal antibodies

The authors investigated the frequency and quantity of intrathecal antibody synthesis against Chlamydia pneumoniae and the presence of C pneumoniae antigen in 25 children with MS. C pneumoniae genome was present in two children. In seven children an intrathecal synthesis of C pneumoniae antibodies was detected, representing only a small part of the total intrathecal immunoglobulin G, suggesting that this intrathecal synthesis is part of a polyspecific, oligoclonal immune response.

Intrathecal immune response pattern for improved diagnosis of central nervous system involvement in trypanosomiasis

Diagnosis of central nervous system (CNS) involvement in human African trypanosomiasis is crucial in determination of therapy. Cerebrospinal fluid (CSF) and serum immunoglobulin concentrations, blood-CSF barrier dysfunction, pattern of intrathecal immunoglobulin synthesis, trypanosome-specific antibody synthesis, and CSF lactate concentrations were analyzed in 272 patients with Trypanosoma brucei gambiense infection. As part of the 2- or 3-class immune response, the predominant intrathecal IgM synthesis was the most sensitive (95%) marker for inflammation of the brain. We propose to replace the World Health Organization (WHO) criteria (white blood cell count >5 cells/microL and presence of trypanosomes in CSF) with a new approach for stage determination in trypanosomiasis: CNS involvement is diagnosed only in patients with >20 cells/microL or with intrathecal IgM synthesis, independent of the presence of trypanosomes in CSF. Compared with the use of these new criteria, the WHO criteria incorrectly classified 49 of 234 patients in the meningoencephalitic stage and 7 of 38 patients in the hemolymphatic disease stage. We also show that trypanosomiasis-related immunoglobulin patterns are of value in differential diagnosis.

Quality assurance for cerebrospinal fluid protein analysis: international consensus by an Internet-based group discussion

A group of neurologists and clinical neurochemists representing twelve countries worked towards a consensus on laboratory techniques to improve the quality of analysis and interpretation of cerebrospinal fluid (CSF) proteins. Consensus was approached via a virtual Lotus Notes-based TeamRoom. This new approach respecting multicultural differences, common views, and minority opinions, is available in http://www.teamspace.net/ CSF, presenting the implicit, complementary version of this explicit, printed consensus. Three key recommendations were made: CSF and (appropriately diluted) serum samples should be analyzed together in one analytical run, i.e., with reference to the same calibration curve. Results are evaluated as CSF/serum quotients, taking into account the non-linear, hyperbolic relation between immunoglobulin (Ig)- and albumin-quotients rather than using the linear IgG index or IgG synthesis rate. Controls should include materials with values within the reference ranges (IgM: 0.5-1.5 mg/l; IgA: 1-3 mg/l; IgG: 10-30 mg/l and albumin: 100-300 mg/l). The physiological, methodological and clinical significance of CSF/serum quotients is reviewed. We confirmed the previous consensus on oligoclonal IgG, in particular the usefulness of the five typical interpretation patterns. The group compared current external and internal quality assurance schemes and encouraged all members to maintain national or local traditions. Values for acceptable imprecision in the CSF quality assurance are proposed.

Proteins in cerebrospinal fluid and blood: barriers, CSF flow rate and source-related dynamics

Cerebrospinal fluid (CSF) routine analysis for diagnosis of neurological diseases is based on the concepts for discrimination of blood-derived and brain-derived immunoglobulin fractions in CSF. The actual molecular flux/CSF flow theory of the blood/CSF barrier function, which founded the hyperbolic discrimination lines in quotient diagrams, is derived from the laws of molecular diffusion combined with CSF flow rate. It emerged from this theory that the decrease of CSF flow rate is sufficient to explain quantitatively the increase of CSF protein concentrations as observed in many neurological diseases. With this concept of CSF flow rate as the modulator of the normal and pathological blood-CSF barrier function, we got for the first time a theoretical frame work to explain also quantitatively the dynamics of brain-derived proteins and their source related (neurons and glial cells or leptomeningal cells) differences. The review of the anatomical, physiological and biophysical knowledge points to the new interpretations: The changing albumin quotient is an indicator of changing CSF flow rate and not for a morphological "leakage" of the blood-brain barrier. As an application of these concepts the dynamics of brain-derived molecules in blood are discussed with two examples: beta trace protein, flowing with CSF into venous blood, and neuron-specific enolase, passing from tissue into blood the opposite direction of serum proteins, again a gradient-dependent protein diffusion across the intact blood vessel wall.

[Intrathecal synthesis pattern of immunoglobulins in meningoencephalitis epidemic due to echovirus 9]

INTRODUCTION

Epidemics of meningoencephalitis due to echovirus 9 were commonly occurred when a children population become susceptible for the first time in front the virus.

OBJECTIVE

To present the intrathecal synthesis pattern of immunoglobulins of the epidemic that affected Cuba in 1999 and to probe the usefulness of reibergram and antibody index in the diagnostic and characterization of the outbreak.

PATIENTS AND METHODS

23 pediatric patients suffering from viral meningoencephalitis due to echovirus 9 were studied in the income moment. Serum and cerebrospinal fluid IgA, IgM, IgG, albumin and glucose were quantified. Cerebrospinal fluid total protein content and lactate were quantified. Titles of antibodies against echo 9 and Coxsackie A9 and differential cell count were performed.

RESULTS

A mean of 555 cells/10 6 L mainly lymphocytes were obtained. Glucose in cerebrospinal fluid was over 50%, serum glucose and lactate levels below 2.1 mmol/L. In the reibergram an absence of intrathecal synthesis was predominant (15/23), IgM synthesis (6/23) and IgM+IgA (2/23). Blood cerebrospinal fluid dysfunction was observed in 15 patients. The mean antibody index was 1,8 for echo 9 and 0,9 for Coxsackie A9.

CONCLUSIONS

The intrathecal synthesis pattern of immunoglobulins was different from other enterovirus and from echovirus 9 in non epidemic situations before this epidemic, probably with alteration of viral genome.