The significance of serum oligoclonal bands in neurological diseases

Diagnostic significance of IgG and albumin indices versus oligoclonal band types in demyelinating disorders

AIMS

The laboratory diagnosis of demyelinating inflammatory disorders (DIDs) relies on both intrathecal oligoclonal band (OCB) positivity and IgG index. Although OCB typing remains the gold-standard test for DIDs, it can be laborious and ambiguous, complicating diagnostics, and unduly increasing diagnostic time. We examined whether serum or cerebrospinal fluid (CSF) parameters can classify OCB types and, thus, be used as a replacement test to standard OCB typing.

METHODS

We retrospectively analysed >1000 prospectively collected samples of patients with DIDs and quantified albumin and IgG levels in the CSF and serum. We determined OCB types by isoelectric focusing combined with immunofixation and evaluated the diagnostic accuracies of IgG and albumin indices in discriminating OCB types by receiver operating characteristic curves and multinomial regression.

RESULTS

An IgG index cut-off of 0.589 differentiated types 2/3 from types 1/4 (area under the curve 0.780, 95% CI 0.761 to 0.812, p<0.001; specificity: 71.10%, sensitivity: 73.45%). Albumin quotient cut-off values of 6.625 and of 6.707 discriminated type 1 from type 4 and type 2 from type 3, respectively (specificity: <55%, sensitivity: <75%). Female sex, age, IgG index, CSF IgG and serum albumin were associated with different OCB types.

CONCLUSIONS

Our study reveals that IgG and albumin index can differentiate OCB types with adequate accuracy, especially if refined by age and gender.

Cerebrospinal Fluid and Clinical Profiles in Adult Type 2-3 Spinal Muscular Atrophy Patients Treated with Nusinersen: An 18-Month Single-Centre Experience

BACKGROUND AND OBJECTIVES

Nusinersen was approved as the first disease-modifying therapy in spinal muscular atrophy (SMA). Our aim was to analyse therapy-related changes in cerebrospinal fluid (CSF) and serum parameters of adult type 2-3 SMA and to correlate biochemical data with motor functional status.

METHODS

Nine adult SMA type 2-3 patients and ten control subjects without neurodegenerative diseases were included in our single-centre study. Cross-sectional analysis of CSF routine parameters, CSF neurofilament light chain, CSF Tau, CSF phospho-Tau and serum creatinine was performed between SMA patients at baseline (T0) and control subjects. The above-mentioned fluid parameters were longitudinally analysed in the SMA cohort after loading dose (T1) and after four maintenance doses (T2, T3, T4, T5). Hammersmith Functional Motor Scale Expanded (HFMSE), Revised Upper Limb Module (RULM) and the 6-minute walking test (6MWT) were used to evaluate motor outcomes.

RESULTS

Improvements in HFMSE, RULM and 6MWT were observed only after the loading dose of nusinersen. No significant differences in routine CSF parameters and CSF markers of neurodegeneration were found between SMA patients and control subjects. Serum creatinine levels were significantly lower in SMA patients than in control subjects. CSF/serum albumin ratio (Qalb) significantly increased from T0 to each time point, without any further increase after the maintenance doses. Persistent systemic oligoclonal bands (OCBs) were found in five patients from baseline. Three more patients developed persistent systemic OCBs from T1; one patient showed intrathecal OCBSs from baseline to T5. Markers of neurodegeneration did not change during the follow-up and did not correlate with motor scores at baseline and at each timepoint. Serum creatinine levels significantly correlated with HFMSE and RULM at each time point.

CONCLUSIONS

The increase of the Qalb values and the development of systemic OCBs in some SMA patients could be due to repeated lumbar puncture and to the immunogenic effect of nusinersen. On the other hand, the presence of OCBs in serum and/or CSF at baseline should be further investigated. Furthermore, biomarkers of neurodegeneration did not play a prognostic role in our cohort of adult SMA patients.

Subacute Cognitive Impairment in Individuals With Mild and Moderate COVID-19: A Case Series

Background: Previous reported neurologic sequelae associated with SARS-CoV-2 infection have mainly been confined to hospital-based patients in which viral detection was restricted to nasal/throat swabs or to IgM/IgG peripheral blood serology. Here we describe seven cases from Brazil of outpatients with previous mild or moderate COVID-19 who developed subacute cognitive disturbances.

Methods: From June 1 to August 15, 2020, seven individuals 18 to 60 years old, with confirmed mild/moderate COVID-19 and findings consistent with encephalopathy who were observed >7 days after respiratory symptom initiation, were screened for cognitive dysfunction. Paired sera and CSF were tested for SARS-CoV-2 (IgA, IgG ELISA, and RT-PCR). Serum and intrathecal antibody dynamics were evaluated with oligoclonal bands and IgG index. Cognitive dysfunction was assessed by the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and the Clock Drawing Test (CDT).

Results: All but one of our patients were female, and the mean age was 42.6 years. Neurologic symptoms were first reported a median of 16 days (IQR 15–33) after initial COVID-19 symptoms. All patients had headache and altered behavior. Cognitive dysfunction was observed mainly in phonemic verbal fluency (MoCA) with a median of six words/min (IQR 5.25–10.75) and altered visuospatial construction with a median of four points (IQR 4–9) (CDT). CSF pleocytosis was not detected, and only one patient was positive for SARS-Co

Conclusions: A subacute cognitive syndrome suggestive of SARS-CoV-2-initiated damage to cortico-subcortical associative pathways that could not be attributed solely to inflammation and hypoxia was present in seven individuals with mild/moderate COVID-19.

Atypical case of Miller-Fisher syndrome presenting with severe dysphagia and weight loss

A 71-year-old man developed dysphagia, bilateral lower extremity muscle weakness and weight loss. He was admitted to the hospital after a failed formal swallow evaluation, nearly 3 weeks after symptom onset. In addition to dysphagia and weakness, physical examination was notable for hypophonia, dysarthria, diplopia, horizontal ophthalmoparesis, ptosis, ataxia and hyporeflexia. Cerebrospinal fluid was notable for albuminocytological dissociation and serum anti-GQ1b antibody titre was elevated (1:200). A diagnosis of Miller-Fisher syndrome (MFS) was made, and the patient was treated with intravenous immunoglobulin (0.4 g/kg/day) for 5 days, which resulted in resolution of symptoms. This is an atypical case of MFS, in that the presenting symptom was progressive dysphagia rather than the ophthalmoplegia and ataxia that are normally seen in MFS. Patients who present with dysphagia should receive a thorough neurological examination, with particular attention to extraocular movements, reflexes and gait stability, to rule out MFS as a potential cause.

Distinguishing neurosarcoidosis from multiple sclerosis based on CSF analysis: A retrospective study

OBJECTIVE

To characterize a cohort of patients with neurosarcoidosis with particular focus on CSF analysis and to investigate whether CSF values could help in distinguishing it from multiple sclerosis (MS).

METHODS

This retrospective cohort study enrolled 85 patients with a diagnosis of neurosarcoidosis (possible, probable, or definite). CSF total protein, white cell count, and angiotensin-converting enzyme levels were measured. CSF and serum oligoclonal immunoglobulin G (IgG) patterns were analyzed with the use of odds ratios and binary logistic regression.

RESULTS

Eighty patients had a probable (nonneural positive histology) or definite (neural positive histology) diagnosis of neurosarcoidosis. Most frequent findings on MRI were leptomeningeal enhancement (35%) and white matter and spinal cord involvement (30% and 23%). PET scan showed avid areas in 74% of cases. CSF analysis frequently showed lymphocytosis (63%) and elevated protein (62%), but CSF-selective oligoclonal bands were rare (3%). Serum ACE levels were elevated in 51% of patients but in only 14% of those with isolated neurosarcoidosis. Elevated CSF ACE was not found in any patient.

CONCLUSIONS

Large elevations in total protein, white cell count, and serum ACE occur in neurosarcoidosis but are rare in MS. The diagnostic use of these tests is, however, limited because minimal changes may occur in both. MS clinical mimics in neurosarcoidosis are not common, and intrathecal synthesis of oligoclonal IgG is a powerful discriminator because it is rare in neurosarcoidosis but occurs in 95% to 98% cases of MS. We suggest caution in making a diagnosis of neurosarcoidosis when intrathecal oligoclonal IgG synthesis is found.

Validation and Implementation of an Ordering Alert to Improve the Efficiency of Monoclonal Gammopathy Evaluation

OBJECTIVES

To evaluate the use of a provider ordering alert to improve laboratory efficiency and reduce costs.

METHODS

We conducted a retrospective study to assess the use of an institutional reflex panel for monoclonal gammopathy evaluation. We then created a clinical decision support (CDS) alert to educate and encourage providers to change their less-efficient orders to the reflex panel.

RESULTS

Our retrospective analysis demonstrated that an institutional reflex panel could be safely substituted for a less-efficient and higher-cost panel. The implemented CDS alert resulted in 79% of providers changing their high-cost order panel to an order panel based on the reflex algorithm.

CONCLUSIONS

The validated decision support alert demonstrated high levels of provider acceptance and directly led to operational and cost savings within the laboratory. Furthermore, these studies highlight the value of laboratory involvement with CDS efforts to provide agile and targeted provider ordering assistance.

The diagnostic value of IgG index versus oligoclonal bands in cerebrospinal fluid of patients with multiple sclerosis

Background

Diagnostic criteria for multiple sclerosis have been developed to guide the diagnostic process. In the latest revision of the McDonald criteria, the presence of oligoclonal bands may replace the need for dissemination in time. The aim of this study is to investigate if the less time-consuming analysis of immunoglobulin G index in cerebrospinal fluid can safely predict the findings of oligoclonal bands.

Methods

This is a retrospective study of patients with multiple sclerosis at three hospitals in South-East Norway where lumbar puncture is performed routinely. We included patients diagnosed with multiple sclerosis after 2005 with known oligoclonal band status and an immunoglobulin G index score.

Results

Of 1295 patients diagnosed during or after 2005, 93.8% were oligoclonal band positive at diagnosis. Of 842 multiple sclerosis patients with known immunoglobulin G index and oligoclonal band status, 93.3% were oligoclonal band positive and 76.7% had an elevated immunoglobulin G index. The positive predictive value of a high immunoglobulin G index when oligoclonal bands are positive was 99.4% (95% confidence interval 98.4–99.8%). The negative predictive value of a normal immunoglobulin G index when oligoclonal bands are negative was 26.5% (95% confidence interval 23.5–29.9%).

Conclusion

An immunoglobulin G index >0.7 has a positive predictive value >99% for oligoclonal bands. An elevated immunoglobulin G index adds diagnostic value versus oligoclonal bands and saves time in the diagnostic process.

Oligoclonal bands and levels of interleukin 4, interleukin 10, and tumor necrosis factor alpha in idiopathic intracranial hypertension Egyptian patients

Background

Idiopathic intracranial hypertension (IIH) is a neurological disorder of unknown pathophysiology with many proposed theories that involve CSF dynamics but recently, involvement of inflammatory and autoimmune processes has been postulated.

Objectives

To investigate presence of oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and serum cytokine level in patients with IIH.

Methods

This study was conducted on 27 IIH female patients and 21 age- and sex-matched control groups. Patient and control groups were subjected to measurement of interleukin-4 (IL-4), IL-10, and tumor necrosis factor α (TNF-α) levels in serum, and CSF oligoclonal bands was measured in the IIH patient group. Body mass index (BMI) was measured to both patients and control.

Results

Serum levels of IL-4, IL-10, and TNF alpha were significantly higher in IIH patients than controls (p <  0.001); 22% of IIH patients had positive OCB in CSF. There was a statistically significant difference regarding TNF-α level in OCB-positive and OCB-negative patients being higher in positive patients. No statistically significant correlation was found between serum levels of IL-4, IL-10, TNF-α, and BMI.

Conclusion

Autoimmune inflammatory process may play a role in pathophysiology of IIH.

Estimation of intrathecal IgG synthesis: simulation of the risk of underestimation

Objective

The low level of passively diffused IgG through the blood–brain barrier is sufficient to blur the estimation of intrathecal IgG synthesis (ITS). Therefore, this estimation requires a mathematical calculation derived from empirical laws, but the range of normal values in healthy controls is wide enough to prevent a precise calculation. This study investigated the precision of various methods of ITS estimations and their application to two clinical situations: plasma exchange and immune suppression targeting ITS.

Methods

Based on a mathematical model of ITS, we constructed a population of healthy controls and applied a tunable ITS.

Results

We demonstrate the following results: underestimation of ITS is common at individual level but true ITS is well fitted by cohorts; Q_IgG increases after plasma exchange; IgG_Loc calculation based on Qlim falsely increases when Q_Alb decreases; the sample size required to demonstrate a decrease in ITS increases exponentially with larger Q_Alb.

Interpretation

Studies evaluating changes in ITS level should be adjusted to Q_Alb. Low amounts of ITS could be largely underestimated.

The Complex Diagnostic Challenge in Children With Non-Central Nervous System Cancer and Cerebellar Mutism

Multiple etiologies should be considered in the differential diagnosis of immunocompromised patients with non-central nervous system cancer and viral infections who develop mutism. Acute cerebellitis, caused by infections or by neurotoxicity resulting from chemotherapy; paraneoplastic cerebellar degeneration; atypical posterior reversible encephalopathy syndrome; and acute disseminated encephalomyelitis may all cause mutism in such patients. This condition warrants prompt recognition and may require treatment with immunotherapy, as it may be an immune-mediated process. We present 2 patients with leukemia and viral illness who developed cerebellar mutism in the setting of acute cerebellitis and responded to immunotherapy, suggesting that the condition involved a parainfectious immune-mediated response.

Serum Free Light Chain Assay and κ/λ Ratio: Performance in Patients With Monoclonal Gammopathy-High False Negative Rate for κ/λ Ratio

Background

Serum free light chain assay (SFLCA) and κ/λ ratio, and protein electrophoretic methods are used in the diagnosis and monitoring of monoclonal gammopathies.

Methods

Results for serum free light chains, serum and urine protein electrophoreses and immunofixation electrophoreses in 468 patients with a diagnosis of monoclonal gammopathy were compared. The results of the two methods were graded as concordant, non-concordant or discordant with the established diagnoses to assess the relative performance of the methods. Results of κ/λ ratio in samples with monoclonal protein detectable by electrophoretic methods were also analyzed.

Results

Protein electrophoreses results were concordant with the established diagnoses significantly more often than κ/λ ratio. The false negative rate for κ/λ ratio was higher than that for electrophoretic methods. κ/λ ratio was falsely negative in about 27% of the 1,860 samples with detectable monoclonal immunoglobulin. The false negative rate was higher in lesions with lambda chains (32%) than those with kappa chains (24%). The false negative rate for κ/λ ratio was over 55% in samples with monoclonal gammopathy of undetermined significance. Even at first encounter, the false negative rates for κ/λ ratios for monoclonal gammopathy of undetermined significance, smoldering myeloma and multiple myeloma were 66.98%, 23.08%, and 30.15%, respectively, with false negative rate for lambda chain lesions being higher.

Conclusions

Electrophoretic studies of serum and urine are superior to SFLCA and κ/λ ratio. Abnormal κ/λ ratio, per se, is not diagnostic of monoclonal gammopathy. A normal κ/λ ratio does not exclude monoclonal gammopathy. False negative rates for lesions with lambda chain are higher than those for lesions with kappa chains. Electrophoretic studies of urine are underutilized. Clinical usefulness and medical necessity of SFLCA and κ/λ ratio is of questionable value in routine clinical testing.

Serum Free Light Chain Assay and κ/λ Ratio Performance in Patients Without Monoclonal Gammopathies: High False-Positive Rate

OBJECTIVES

Serum free light chain assay is a recommended screening test for monoclonal gammopathies. Anecdotal observations indicated a high rate of false-positive abnormal κ/λ ratios. This study was undertaken to ascertain the magnitude of the false-positive rate and factors contributing to the error rate.

METHODS

Results of serum protein electrophoresis, serum free light chains, and related tests, usually done for investigation of suspected monoclonal gammopathy, were reviewed retrospectively for 270 patients and 297 observations.

RESULTS

Using the conventional κ/λ ratio, 36.4% of the ratios were abnormal, in the absence of monoclonal gammopathy. When the renal κ/λ ratio was used, the rate of abnormal κ/λ ratios was 30.1%. In patients with a γ-globulin concentration of 1.6 g/dL or more, the usual κ/λ ratio was abnormal in 54.8% of the patients. Urine protein electrophoresis was used in 53 (19.6%) instances, whereas bone marrow examination was done in 65 (24.1%) cases.

CONCLUSIONS

Usual κ/λ ratio was abnormal in 36.4% of the observations in patients without evidence of monoclonal gammopathy, and an abnormal κ/λ ratio should not be used as the sole indicator for diagnosis of neoplastic proliferation of the lympho-plasmacytic system. Hypergammaglobulinemia is associated with a higher rate of false-positive abnormal κ/λ ratios. Examination of urine for monoclonal immunoglobulins may be underused, and recommendations by some to use serum free light chain assay in place of, rather than as an adjunct to, urine electrophoresis are not warranted.

Audit of Use and Overuse of Serum Protein Immunofixation Electrophoresis and Serum Free Light Chain Assay in Tertiary Health Care: A Case for Algorithmic Testing to Optimize Laboratory Utilization

OBJECTIVES

Overuse of laboratory tests is a persistent issue. We examined the use and overuse of serum immunofixation electrophoresis and serum free light chain assays to develop an algorithm for optimizing utilization.

METHODS

A retrospective review of all tests, for investigation of monoclonal gammopathies, for all patients who had any of these tests done from April 24, 2014, through July 25, 2014, was carried out. The test orders were categorized as warranted or not warranted according to criteria presented in the article.

RESULTS

A total of 237 patients were tested, and their historical records included 1,503 episodes of testing for one or more of serum protein electrophoresis, serum immunofixation electrophoresis, and serum free light chain assays. Only 46% of the serum immunofixation and 42% serum free light chain assays were warranted. Proper utilization, at our institution alone, would have obviated $64,182.95/year in health care costs, reduced laboratory cost of reagent alone by $26,436.04/year, and put $21,904.92/year of part B reimbursement at risk.

CONCLUSIONS

Fewer than half of the serum immunofixation and serum free light chain assays added value. The proposed algorithm for testing should improve utilization. Risk to part B billing may be a disincentive to reducing test utilization.

Oligoclonal bands and increased cytokine levels in idiopathic intracranial hypertension

OBJECTIVES

The pathogenesis of idiopathic intracranial hypertension (IIH) is currently unknown and there are speculations about the contribution of some immunologic factors. The aim of this study is to investigate the presence of oligoclonal bands (OCBs) and cerebrospinal fluid (CSF) and/or serum cytokine levels in patients with IIH.

METHODS

Patients fulfilling revised diagnostic criteria for IIH were included. Their demographic, clinical, ophthalmologic and laboratory features were examined. Serum and CSF samples were detected by isoelectric focusing and immunoblotting for OCBs. The samples of IIH patients and control groups were investigated by ELISA for cytokine levels.

RESULTS

We detected OCBs in eight (30.77%) patients diagnosed with IIH. There were no other obvious clinical and laboratory differences of IIH profiles between the patients with and without OCBs, but frequency of vision loss was significantly higher in the group with OCBs in comparison to OCB negatives (p = 0.038). Patients with IIH had highly elevated TNF-α, IFN-γ, IL-4, IL-10, IL-12, IL-17 in their sera compared to patients with multiple sclerosis (MS) and healthy controls. Furthermore, all cytokines except TNF-α in the CSF were found significantly higher in IIH patients compared to MS controls.

CONCLUSION

The presence of OCBs and elevated cytokine levels in IIH patients may support an immunologic background in the pathophysiological pathway of this disorder.

Impairments in Episodic-Autobiographical Memory and Emotional and Social Information Processing in CADASIL during Mid-Adulthood

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) - is the most common genetic source of vascular dementia in adults, being caused by a mutation in NOTCH3 gene. Spontaneous de novo mutations may occur, but their frequency is largely unknown. Ischemic strokes and cognitive impairments are the most frequent manifestations, but seizures affect up to 10% of the patients. Herein, we describe a 47-year-old male scholar with a genetically confirmed diagnosis of CADASIL (Arg133Cys mutation in the NOTCH3 gene) and a seemingly negative family history of CADASIL illness, who was investigated with a comprehensive neuropsychological testing battery and neuroimaging methods. The patient demonstrated on one hand severe and accelerated deteriorations in multiple cognitive domains such as concentration, long-term memory (including the episodic-autobiographical memory domain), problem solving, cognitive flexibility and planning, affect recognition, discrimination and matching, and social cognition (theory of mind). Some of these impairments were even captured by abbreviated instruments for investigating suspicion of dementia. On the other hand the patient still possessed high crystallized (verbal) intelligence and a capacity to put forth a façade of well-preserved intellectual functioning. Although no definite conclusions can be drawn from a single case study, our findings point to the presence of additional cognitive changes in CADASIL in middle adulthood, in particular to impairments in the episodic-autobiographical memory domain and social information processing (e.g., social cognition). Whether these identified impairments are related to the patient's specific phenotype or to an ascertainment bias (e.g., a paucity of studies investigating these cognitive functions) requires elucidation by larger scale research.

CSF albumin and immunoglobulin analyses in childhood neurologic disorders

Objective:

To evaluate the utility of qualitative and quantitative analyses of CSF immunoglobulins as part of the diagnostic workup of CNS inflammatory conditions.

Methods:

One hundred eighty-nine children who underwent CSF investigation for their neurologic condition had CSF and serum testing to (1) qualitatively identify oligoclonal band (OCB) patterns and (2) quantitatively measure the immunoglobulin (Ig) G index and albumin quotient (Q_Alb). Case notes were retrospectively reviewed and patients were grouped according to whether their primary diagnosis was due to an inflammatory (n = 104) or noninflammatory (n = 85) etiology.

Results:

CSF-restricted OCBs were found in 20/104 (19%) of the inflammatory group compared with 4/85 (5%) of the noninflammatory group (p= 0.0036). Mirrored OCBs were found in 13/104 (12.5%) of the inflammatory group compared with 5/85 (6%) of the noninflammatory group (p = 0.14). IgG index and Q_Alb were significantly higher in patients with an inflammatory etiology. However, a raised IgG index (>0.85) and Q_Alb (>0.049) were seen in both groups, with Q_Alb abnormalities seen more frequently in the inflammatory group (p = 0.0028).

Conclusions:

Both methods were informative in identifying inflammatory mechanisms. Abnormalities were more commonly, but not exclusively, seen in primary inflammatory conditions. The qualitative and quantitative evaluation collectively revealed additional positive results than when done in isolation.

IgG4 specific to Toxoplasma gondii excretory/secretory antigens in serum and/or cerebrospinal fluid support the cerebral toxoplasmosis diagnosis in HIV-infected patients

Cerebral toxoplasmosis is the most common neurological opportunistic disease manifested in HIV infected patients. Excretory/secretory antigens (ESA) are serological markers for the diagnosis of reactivation of the infection in HIV-infected patients with cerebral toxoplasmosis. Immunosuppressed patients develop high antibody titers for ESA. However, little is known about the humoral response for these antigens. The present study analyzed the profile of antibody recognition against ESA in comparison with tachyzoite lysate antigen (TLA) in 265 sera and 270 cerebrospinal fluid (CSF) samples from infected patients with Toxoplasma gondii and or HIV and in sera of 50 healthy individuals. The samples of sera and CSF were organized in 8 groups. The sera sample groups were: Group I - Se/CT/AIDS (patients with cerebral toxoplasmosis/AIDS) with 58 samples; Group II - Se/ONinf/AIDS/PosT (patients with AIDS/other neuroinfections/positive toxoplasmosis) with 49 samples; Group III - Se/ONinf/AIDS/NegT (patients with AIDS/other neuroinfections/negative toxoplasmosis) with 58 samples; Group IV - Se/PosT/NegHIV (individuals with asymptomatic toxoplasmosis/negative HIV) with 50 samples and Group V - Se/NegT/NegHIV (healthy individuals/negative toxoplasmosis and HIV) with 50 samples. The CSF sample groups were: Group VI - CSF/CT/AIDS (patients with cerebral toxoplasmosis/AIDS) with 99 samples; Group VII - CSF/ONinf/AIDS/PosT (patients with AIDS/other neuroinfections/positive toxoplasmosis) with 112 samples, and Group VIII - CSF/ONinf/AIDS/NegT (patients with AIDS/other neuroinfections/negative toxoplasmosis) with 59 samples. Levels of IgM, IgA, IgE, IgG and subclasses were determined by ELISA against TLA and ESA antigens. IgM, IgA or IgE antibodies against ESA or TLA were not detected in sera from patients with toxoplasmosis suggesting that all patients were in chronic phase of the infection. High levels of IgG1 against TLA were found in sera samples from groups I, II and IV and in CSF samples from groups VI and VII; whereas IgG2, IgG3 and IgG4 levels were not detected in the same sera or CSF sample groups. However, patients from groups I and VI, that had tachyzoites circulating in blood and CSF respectively, produced a mix of IgG1 and IgG4 antibodies against ESA. IgG2 against ESA were predominant in serum from patients with the latent (non-active) T. gondii infection/HIV negative and in CSF samples from patients with other neuroinfections and positive toxoplasmosis (groups IV and VII, respectively). IgG4 levels against ESA were found to be significantly (P<0.05 and P<0.005) higher in patients with cerebral toxoplasmosis (groups I and VI, respectively) in comparison with groups II, IV and VII. This data suggest that IgG4 can be valuable for supporting the diagnosis of focal brain lesions, caused by T. gondii infection, in HIV-infected patients. This approach might be useful, mainly when molecular investigation to detect parasites is not available.

Staphylococcal immune complexes and myelinolytic toxin in early acute multiple sclerosis lesions-An immunohistological study supported by multifactorial cluster analysis and antigen-imprint isoelectric focusing

Highly significant clinical, epidemiological and pathogenetic similarities between multiple sclerosis (MS) and nasopharyngeal sinusitis has led to the hypothesis that MS is caused by the inadvertent incorporation of the lymphatic drainage of the nasopharynx into the extracellular fluid circulation of the CNS. It has been postulated that, in response to antigenic and toxic products generated by the mucosal nasopharygeal flora, the leptomeninges and CNS parenchyma acquire the characteristics of a persistently stimulated lymphoid organ. Using an extensive panel of bacterial antibodies, tissues from exceptionally early cases, identified and classified using multifactorial cluster analysis, were screened for bacterial antigens using immunohistological methods. Anti-staphylococcal antibodies detected antigen co-locating with IgG/C3d immune complexes in pre-demyelinating and in primary lesions. The distribution of the antigen in relation to the morphogenesis of early acute MS lesions is detailed. Evidence for the intrathecal processing of staphylococcal antigen was obtained using isoelectric focusing and antigen imprinting to identify antigen-specific oligoclonal bands. Employing a combination of isoelectric focusing, western blotting and mass spectrometric analysis, evidence for the intrathecal processing of staphylococcal β-haemolysin (sphingomyelinase) was obtained using CSF from MS cases. While a myelinolytic transportable toxin may be an important component in the pathogenesis of demyelination, in oligodendrocyte apoptosis, and in deviant immune responses within the CNS, the detection of other as yet unidentified staphylococcal-positive and negative oligoclonal bands points to the involvement of a cocktail of transportable antigens leaking in a similar manner into the CNS from the paranasal sinus mucosal tissues where these molecules are conserved by the resident flora to manipulate and subvert the normal processes of local and systemic immunity. Evidence for the access of other bacterial transportables to the CNS in MS should now be sought. The presence of 'high-output' toxigenic bacterial strains within the nasopharyngeal flora of MS patients should also be explored. The use of tracer molecules to detect and quantify nose-to-brain transport in MS patients is clearly apposite.

Toxoplasma gondii infection and cerebral toxoplasmosis in HIV-infected patients

Cerebral toxoplasmosis is a major cause of morbidity and mortality among HIV-infected patients, particularly from developing countries. This article summarizes current literature on cerebral toxoplasmosis. It focuses on: Toxoplasma gondii genetic diversity and its possible relationship with disease presentation; host responses to the parasite antigens; host immunosupression in HIV and cerebral toxoplasmosis as well as different diagnostic methods; clinical and radiological features; treatment; and the direction that studies on cerebral toxoplasmosis will likely take in the future.

IL-15 is elevated in serum and cerebrospinal fluid of patients with multiple sclerosis

Interleukin-15 (IL-15) is a novel proinflammatory cytokine having similar biological activities to IL-2 which is implicated in the pathogenesis of multiple sclerosis. It is produced by activated blood monocytes, macrophages and glial cells. There is little information about the involvement of IL-15 in the development of multiple sclerosis (MS). The objective of our study was to measure IL-15 serum and cerebrospinal fluid (CSF) levels in MS patients and to correlate serum and CSF IL-15 concentrations with clinical parameters of the disease. CSF IL-15/Serum IL-15 ratio (c/s IL-15 ratio) was introduced to assess the origin of elevated IL-15 levels.

MATERIALS AND METHODS

We measured serum and CSF IL-15 levels in 52 patients with MS and 36 age and gender matched patients with inflammatory (IND) and non-inflammatory neurological diseases (NIND) studied as control groups. IL-15 levels were correlated with clinical parameters as duration, disability, MRI activity and clinical subtypes of the disease.

RESULTS

MS patients were found to have significantly higher serum IL-15 levels compared with IND (p=0.00016) and NIND patients (p=0.00045). Elevated levels of IL-15 were also found in CSF samples from MS patients compared with patients with IND (p=0.00034) and NIND (p=0.0003). Among MS subgroups there were no statistically different IL-15 serum and CSF concentrations. No significant correlation of serum and CSF IL-15 concentrations with MRI activity, disability assessed by EDSS score and duration of the disease were also found. C/S IL-15 ratio was found lower in MS patients compared with IND (p=0.01) and not significantly different compared with NIND patients (p=0.14) suggesting that systemic activation might be the source of high CSF IL-15 levels in MS patients.

CONCLUSIONS

Our findings suggest a possible role of IL-15 in the immunopathogenetic mechanisms of MS.

[Oligoclonal IgG bands in the cerebrospinal fluid of portuguese patients with multiple sclerosis: negative results indicate benign disease]

We assessed the frequency of cerebrospinal fluid (CSF) restricted oligoclonal IgG bands (IgG-OCB) in Portuguese multiple sclerosis (MS) patients and its relationship with outcome. Paired CSF/serum samples of 406 patients with neurological disorders were submitted to isoelectric focusing with immunodetection of IgG. Ninety-two patients had definite MS; non-MS cases were assembled in groups inflammatory/infectious diseases (ID, n=141) and other/controls (OD, n=173). We found in the MS group: mean duration, 38.9 months; clinically isolated syndromes, 24%; relapsing/remitting course (RR), 65%; in RR patients the mean EDSS was 2.1 and the mean index of progression was 0.31. Positive patterns significantly predominated in MS (82.6%; ID, 40.4%; OD, 3.5%). The sensitivity and the specificity of positive IgG-OCB for MS diagnosis was 82.6% and 79.9%, respectively. The sole statistically significant difference in the MS group was the lower progression index observed in negative cases. We conclude that the frequency of positive IgG-OCB patterns in our MS patients fits most values reported in the literature, and that negative results indicate benign disease.

Peptide repertoire of human cerebrospinal fluid: novel proteolytic fragments of neuroendocrine proteins

Polypeptides in human cerebrospinal fluid (CSF), isolated by phase separation in chloroform-methanol-water and reversed-phase HPLC, were characterised by sequence analysis and mass spectrometry. This identified the presence of peptide fragments of testican, neuroendocrine specific protein VGF, neuroendocrine protein 7B2, chromogranin B/secretogranin I, chromogranin A, osteopontin, IGF-II E-peptide and proenkephalin. The majority of these fragments were generated by proteolysis at dibasic sites, suggesting that they are derived by activities related to prohormone convertase(s). Several of the fragments have previously not been detected, and their functions in CSF or elsewhere are unknown. A characteristic feature of all these fragments is a very high content of acidic residues, in particular glutamic acid. In addition to the fragments of neuroendocrine proteins, endothelin-binding receptor-like protein 2, ribonuclease 1, IGF-binding protein 6, albumin, alpha1-acid glycoprotein 1, prostaglandin-H2 D-isomerase, apolipoprotein A1, transthyretin, beta2-microglobulin, ubiquitin, fibrinopeptide A, and C4A anaphylatoxin were found.

Infectious etiology in multiple sclerosis: the debate continues

‘Demonstrating Infectious Cause: Viral and Bacterial Infections in MS and Related Disorders’ was held in Brighton, UK, 23–25 August 1999.

Autoimmunity in Waldenström's macroglobulinaemia

Fifty-seven consecutive patients with Waldenström's Macroglobuliemia were studied retrospectively for autoimmune manifestations. 28 patients or 51% (16 women and 13 men) had clinical and/or serological autoimmune manifestations, two or more of these being concomitant in 20 (12 women and 8 men). The predominant findings were Coombs' positive autoimmune hemolytic anemia (16%), seropositive rheumatoid arthritis (16%), inflammatory gastric ulcer with parietal cell autoantibodies (12%), and IgM-cardiolipin syndrome (11%). 40% of the autoimmune manifestations were present at the time of diagnosis of the Waldenström's Macroglobulinaemia and 60% were observed over a mean period of 4.7 years. All patients had an IgM M-component. There was no correlation between autoimmunity and the size of the M-component or the degree of hypo-IgG and hypo-IgA gammaglobulinemia. The only correlation between autoimmunity and infection was found in patients with gastric ulcer and parietal cell autoantibodies, in whom the infection was caused by Helicobacter pylori.

Identification of IgG-specific oligoclonal banding in serum and cerebrospinal fluid by isoelectric focusing: description of a simplified method for the diagnosis of neurological disorders

Clinical laboratory procedures using cerebrospinal fluid (CSF) to assist in the diagnosis of multiple sclerosis (MS) are based essentially on the determination of oligoclonal bands (OB) in CSF and not in serum. To date, the techniques using isoelectric focusing (IEF) have represented one of the most efficient methods for detecting supernumerary bands in CSF but unfortunately were not always compatible with a routine use. Here, we describe a revised method of IEF suitable for the diagnosis of neurological disorders. The kit-based technique was simplified and the present procedure allowed an easier execution, reduced the overall analysis time and permitted an uncomplicated intepretation of oligoclonal profiles. Moreover, the technique developed was very sensitive and specific for the diagnosis of MS diagnosis. In conclusion, the IEF protocol described in this report is suitable for OB detection in any laboratory.

Advanced laboratory techniques for diagnosing Toxoplasma gondii encephalitis in AIDS patients: significance of intrathecal production and comparison with PCR and ECL-western blotting

The polymerase chain reaction (PCR) for detection of cerebral spinal fluid (CSF) Toxoplasma gondii DNA was combined with the study of intrathecal antibody synthesis by antibody specific index calculation (ASI) and the detection of specific oligoclonal IgG bands (OCB) by affinity mediated immunoblotting (AMI) in 11 AIDS patients with T. gondii encephalitis (TE) and in 20 control patients with or without neurological disorders. Enhanced chemiluminescence (ECL) western-blot technique was employed to evaluate the antigenic specificity of CSF-IgG towards individual T. gondii antigens. PCR was positive in all TE patients which displayed brain-derived or blood-derived specific OCB, even when comparative ASI failed. Four TE patients had a unique anti-T. gondii OCB restricted to the CSF and a strong antibody response toward the 29 kDa band by ECL western blot. This response could be an important marker to discriminate TE from other opportunistic central nervous system (CNS) infections in the course of AIDS.

Antigen-specific oligoclonal IgG in AIDS-related cytomegalovirus and toxoplasma encephalitis

We retrospectively studied serum and cerebrospinal fluid (CSF) specimens from AIDS patients with either Cytomegalovirus (2 cases) or Toxoplasma gondii (5 cases) encephalitis. The samples, which had previously proved to be negative for total IgG oligoclonal bands (OCBs), were investigated for antigen-specific OCBs directed to the disease-related opportunistic agent.

MATERIAL & METHODS

Paired serum and CSF samples from the given AIDS patients were considered. We undertook affinity immunoblotting of either virus- or protozoan-specific IgG onto antigen-coated nitrocellulose paper after protein separation by agarose isoelectric focusing (IEF).

RESULTS

Antigen-specific OCBs to the disease-related opportunistic agent were detected in serum and in CSF samples from all the patients.

CONCLUSIONS

During overt AIDS, routine IEF methods may fail to detect OCBs, probably because nonspecific polyclonal hypergammaglobulinemia, which is typical of this disease, reduces their visibility. Our IEF/immunoblotting profiles are characterized by identical serum and CSF bands. The detection of antigen-specific OCBs may support the diagnosis of some opportunistic infections of the central nervous system in AIDS.

Qualitative assessment of intrathecal IgG synthesis by isoelectric focusing and immunodetection: interlaboratory reproducibility and interobserver agreement

Detection of intrathecal IgG synthesis is important in patients with suspected multiple sclerosis (MS). The recommended method for the detection of intrathecal synthesis of IgG is isoelectric focusing and immunodetection of oligoclonal bands. Recently "The Committee for European Concerted Action for Multiple Sclerosis" has recommended that the results of isoelectric focusing for the detection of intrathecal synthesis of oligoclonal bands should not only be stated as positive or negative for intrathecal synthesis; instead, the laboratory should provide a detailed description of the IgG pattern in both cerebrospinal fluid (CSF) and serum together with a conclusion concerning the presence of intrathecal synthesis. We studied the interlaboratory reproducibility and interobserver agreement of isoelectric focusing, and the recommended classification system for the assessment of intrathecal IgG synthesis, in two separate patient groups employing kappa statistics. We found a high degree of interlaboratory reproducibility (133 patients; kappa = 0.95 +/- 0.05) and interobserver agreement (356 patients; kappa = 0.97 +/- 0.04) when the presence or absence of intrathecal IgG synthesis was assessed. The agreement was less pronounced, although still fully satisfactory, when the results were classified according to the detailed system by two laboratories (133 patients; kappa = 0.86 +/- 0.08) and two observers (356 patients; kappa = 0.88 +/- 0.08). Two specific problems in the interpretation of isoelectric focusing patterns were identified: one related to the discrimination of a pattern with several closely spaced bands which may represent a monoclonal protein; the other related to determining whether systemic band synthesis was present. We conclude that isoelectric focusing and immunodetection is a very reproducible technique for the detection of intrathecal IgG synthesis. Well defined criteria and extensive standardization may, however, be necessary when more elaborate classification systems are employed.

A study of oligoclonal band negative multiple sclerosis

OBJECTIVES

To determine whether oligoclonal band (OCB) negative multiple sclerosis is a reliable diagnosis and, if so, whether it has a distinctive prognosis.

METHODS

Retrospective and matched prospective comparison of the clinical and laboratory features of patients with clinical definite multiple sclerosis with and without intrathecal synthesis of oligoclonal IgG.

RESULTS

Thirty four patients were identified with apparent OCB negative clinically definite multiple sclerosis. The results of oligoclonal banding proved to have been equivocal in 14 of 34; the clinical diagnosis of multiple sclerosis was questionable in 8 of 34. The remaining 12 patients with "true" OCB negative multiple sclerosis were significantly less disabled than matched OCB positive controls. Re-examination of CSF-serum pairs from six OCB negative patients showed that three remained OCB negative while three showed evidence of intrathecal synthesis of OCBs.

CONCLUSIONS

OCB negative clinically definite multiple sclerosis is rare and should be diagnosed with caution; in unequivocal cases it seems to have a relatively benign prognosis.

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Intrathecal synthesis of immunoglobulin G and Mycobacterium tuberculosis-specific humoral immune response in tuberculous meningitis

Local synthesis of immunoglobulin G (IgG) in the central nervous system was investigated in 10 patients with tuberculous meningitis (TBM), 15 patients with aseptic meningitis (AM), and 15 patients with pulmonary tuberculosis only (PTBO). The IgG synthesis rate for patients with TBM was 56.4 +/- 18.9 mg/day (mean +/- standard deviation), which was significantly higher than that for patients with AM (8.0 +/- 6.7 mg/day, P < 0.001) and that for patients with PTBO (7.5 +/- 4.4 mg/day, P < 0.001). Therefore, the increased IgG synthesis rate in the central nervous system provided supporting evidence for differentiating the diagnosis of TBM from that of AM (sensitivity, 100%; specificity, 83.3%). Simultaneous measurement by enzyme-linked immunosorbent assay of IgG seroreactivity to lipoarabinomannan and purified protein derivative antigens in cerebrospinal fluid (CSF) demonstrated seropositivity in all 6 patients with TBM, 4 of 15 patients with AM, and 4 of 10 patients with PBTO. All patients showing false-positive reactivity in CSF demonstrated seropositivity in sera and normal ranges for IgG synthesis rates in CSF. Also, the semiquantitive measurement of IgG antibody (Ab) titers in these patients demonstrated higher IgG Ab titers in serum than in CSF except for one patient with a highly elevated albumin quotient, suggesting a leaky blood-brain barrier. The results strongly suggested that the Mycobacterium tuberculosis-specific IgG Abs were diffusible through the blood-brain barrier, which addresses the pitfall of serological tests for the early diagnosis of TBM. The serological detection of IgG Abs to lipoarabinomannan and purified protein derivative antigens in CSF could be misleading in the presence of simultaneously elevated of IgG Abs in serum.

Lymphocytic meningitis following insertion of a porcine dermis dural graft

We describe a case of lymphocytic meningitis following insertion of a porcine dermis implant to repair an operative dural defect. Histology of the excised implant revealed local abscess formation with a granulomatous reaction. Oligoclonal Immunoglobulin G, part of which could be removed by absorbtion with the porcine dermis, was present in the patient's cerebrospinal fluid, and, to a less marked degree, in his serum. The cerebrospinal fluid glucose was markedly depressed. An unusual hypersensitivity reaction to the porcine implant was considered the most likely explanation for this meningitic illness. The patient went on to make a full recovery following excision of the implant.