Polyacrylamide-gel disc electrophoresis of native cerebrospinal fluid proteins with special reference to immunoglobulins and some clinical applications

Cerebrospinal Fluid Protein Concentration in Healthy Older Japanese Volunteers

The concentration of cerebrospinal fluid total protein (CSF-TP) is important for the diagnosis of neurological emergencies. Recently, some Western studies have shown that the current upper reference limit of CSF-TP is quite low for older patients. However, little is reported about the concentration of CSF-TP in the older Asian population. In this study, we retrospectively analyzed the CSF-TP concentrations in healthy older Japanese volunteers. CSF samples in 69 healthy Japanese volunteers (age range: 55–73 years) were collected by lumbar puncture, and the data of CSF were retrospectively analyzed. The mean (standard deviation) CSF-TP was 41.7 (12.3) mg/dL. The older group (≥65 years old) had higher CSF-TP concentration than the younger group (55–64 years old). The 2.5th percentile and 97.5th percentile of CSF-TP were estimated as 22.5 and 73.2 mg/dL, respectively, which were higher than the current reference range in Japan (10–40 mg/dL). Conclusions: The reference interval of CSF-TP in the older population should be reconsidered for the precise diagnosis of neurological emergencies.

Adult CSF total protein upper reference limits should be age-partitioned and significantly higher than 0.45 g/L: a systematic review

BACKGROUND

Cerebrospinal fluid total protein (CSF-TP) is measured in the diagnosis of a range of immune or infectious disorders of the nervous system. Most laboratories and the medical literature use an antiquated, age-independent upper limit of 0.45 g/L. Therefore, we performed a systematic review of reference studies in the medical literature, with the primary objective of determining the CSF total protein upper reference limit (URL). Secondary objectives were to assess the effects of age, gender, laboratory methods, and methodological quality.

METHODS

A pre-planned and peer-reviewed electronic search strategy was used to search Ovid Medline and EMBASE for 1960-2017. All records underwent title/abstract review, and potentially relevant records underwent independent full-text review by two researchers. The remaining studies underwent quality assessment using a modification of the QUADAS2 revised tool. CSF-TP upper reference limits extracted from these studies were used to compute weighted means.

RESULTS

Twenty-two articles were retained for qualitative analysis and 20 for quantitative analysis. The weighted average of CSF-TP URL was 0.55 g/L, in studies with high methodological quality. Studies that examined the effect of age reported consistent correlations with advancing age, and CSF-TP URL values incrementally exceeded 0.60 g/L after age 50. There were no meaningful differences according to gender, laboratory method, or quality assessment score.

CONCLUSIONS

There is concordance in available literature to recommend increasing CSF total protein upper reference limits, and to consider implementing age-adjusted values above 0.60 g/L starting at age 50. This information merits worldwide dissemination, to reduce the risk of over-diagnosis.

Adult CSF total protein: Higher upper reference limits should be considered worldwide. A web-based survey

BACKGROUND

The cerebrospinal fluid total protein level (CSF-TP) is commonly used as a potential marker of infectious or immune disease of the CNS and PNS. Recent laboratory reference studies indicate that the antiquated single upper reference limit of 0.45 g/L commonly used by hospital laboratories and widely quoted in medical literature is a significant underestimation.

METHODS

We distributed worldwide a web-based survey comprised of three questions: 1. What is the CSF-TP upper limit used at your institution? 2. What is the source of this upper limit? 3. Do you adjust your upper limit according to age?

RESULTS

A total of 473 unique responses were obtained from North America (37.5%), South America (5.5%), Europe (29.4%), Africa (4%), Asia (21.6%) and Oceania (1.7%). A strong preponderance (86.8%) of institutions reported an upper limit of 0.45 g/L or less. Only 4% reported making age-partitioned adjustments.

CONCLUSIONS

Worldwide, a strong majority of hospital laboratories presently use an underestimation of CSF-TP upper reference value, particularly for older adults. Recent well powered laboratory reference studies support higher values with age adjustment.

Transfer of specific IgG and IgG subclasses to herpes simplex virus across the blood-brain barrier and placenta in preterm and term newborns

The kinetics of virus-specific IgG subclasses (IgG 1-4) among newborns and their mothers has not yet been determined. In this report, we examined anti-herpes simplex virus IgG activities (HSV-IgG) and its subclasses in CSF and serum of premature or term newborns without HSV infection and in the serum of their mothers using ELISA. We found that CSF/serum ratios of HSV-IgG and IgG subclasses (IgG 1-4) in newborns with a gestational age less than 38 weeks were higher than those of term newborns. These findings indicate that the blood-brain barrier against HSV-IgG and IgG subclasses is insufficient in newborns. Furthermore, we found that HSV-IgG subclasses, which were transferred across the placenta and later transferred across the blood-brain barrier had a tendency to be proportional to each of the maternal HSV-IgG subclasses.

Cerebrospinal fluid protein analysis in diseases of the nervous system

Electrophoretic studies of human CSF proteins from patients with diseases of the NS are reviewed. Various 1-DE methods are of similar value in identifying the non-specific OBs, which are helpful in the diagnosis of MS and recurrent GBS. In early and subclinical MS, OBs are of prognostic value, with IEF gels having the greater resolution. Silver-stained 2-DE gels provide the equivalent information to the OBs on 1-DE gels, with even greater sensitivity, and yield additional disease-associated protein data. Two proteins have proven to have diagnostic value in CJD and other changes that are still being evaluated have been identified in Parkinson's disease, GBS, Alzheimer's disease, schizophrenia and Herpes simplex encephalitis. The vastly improved CSF protein information obtained with silver-stained 2-DE gels heralds both a change from the relatively limited applications with 1-DE methods and also the need to adopt this approach in the routine clinical laboratory.

Cerebrospinal fluid paraproteins in neurological disorders

Paraproteins display a characteristic pattern of limited heterogeneity on isoelectric focusing. In a group of 50 patients with various neurological disorders and paraproteinaemia this pattern could be demonstrated in serum and cerebrospinal fluid simultaneously, regardless of the form of nervous system involvement or of the function of the blood-cerebrospinal fluid barrier. Although there were no qualitative differences in the pattern between paraproteins from benign and malignant cases, a distinct quantitative difference was found: Paraproteins from myeloma patients had significantly more subfractions extending over a wider pH range than paraproteins from patients with benign monoclonal gammopathy. Due to the high sensitivity of isoelectric focusing, more paraproteins could be detected in cases where other electrophoretic methods including immunoelectrophoresis were negative. A surprisingly high percentage of patients was found with benign monoclonal gammopathy and vascular lesions of the central nervous system.

Impairment of blood-cerebrospinal fluid barrier in multiple sclerosis

The blood-CSF barrier (BCB) function in active multiple sclerosis (MS) was studied by means of CSF proteins analysis using disc electrophoresis and immunofixation. Forty-five CSF samples were obtained by repeat lumbar punctures at various intervals, from four autopsy-proven cases and three male and nine female patients with clinically definite MS. When total protein content was increased, the percentages of prealbumin and tau fraction were decreased significantly in association with the presence of haptoglobin (Hp) polymers in nearly all the samples, as a result of increased permeability of the BCB. Even when the total protein content was normal, Hp polymers were detected in 56% of the samples, and the tau fraction tended to be decreased. Monoclonal immunoglobulin and Hp polymers were both recognized in some cases. The results suggested a more frequent occurrence of BCB impairment in MS than had formerly been revealed by CSF albumin analysis, and accorded with the recent reports of contrast-enhancing lesions of MS brain in computerized tomography.

Measurement of body fluid proteins by polyacrylamide gel electrophoresis

A development of the disc polyacrylamide gel electrophoretic system of Ornstein and Davis, which has been applied to the analysis of unconcentrated cerebrospinal fluid, is described. Modifications to the scanning densitometer have improved the signal:noise ratio of the gel scanning system. Using this technique, we have studied the dye-binding properties of albumin, and of beta- and gamma-globulins, and have shown that reproducible quantification of proteins can be achieved. The advantages of electrophoretic methods over immunochemical methods of quantification are discussed.

Characteristic protein fractions of cerebrospinal fluid disc electrophoretic analysis

The present work was undertaken to determine characteristic proteins of normal cerebrospinal fluid (CSF) by disc electrophoresis in polyacrylamide gel, and to evaluate their usefulness as indicators of blood-brain-CSF barrier disturbance. The technique has been applied to 1280 samples of unconcentrated CSF obtained from 27 reference subjects and 847 neurological patients, with a simultaneous analysis of 361 sera. The pre-albumin content (mean +/- S.D. as a percentage of total protein, 11.0 +/- 2.3%) was higher than formerly reported. One reason for this is that preliminary concentration was not necessary, and the second is related to the principle of protein resolution. The no. 5 protein band of the post-albumin group (3.9 +/- 1.1%) was characteristic, though it has not yet been identified. The no. 3 protein band of the post-transferrin group (5.2 +/- 1.7%) was highly specific to CSF; it was found to be closely related to transferrin, and may correspond to tau fraction obtained by other methods. Barrier dysfunction was easily recognizable by the appearance of polymers of haptoglobin 2-1 or 2-2, because only haptoglobin 1-1 was detected in normal CSF. The percentage of the main region of the G-zone (13.7 +/- 2.6%) was postulated as normal content of CSF immunoglobulins.

Polyacrylamide-gel disc electrophoresis of unconcentrated urine samples with special reference to Bence Jones proteins

The polyacrylamide-gel disc electrophoresis has been applied to the fractionation of 27 samples of unconcentrated urine obtained from the patients with monoclonal gammopathy. It was shown that 44% of the whole Bence Jones protein bands examined were detected in the area between 0.70 and 0.90 expressed in terms of relative migration based on transferrin. The method provided a satisfactory separation of native urine proteins with good reproducibility and few technical difficulties. It may become an efficient tool in clinical chemistry.