The clinical value of assaying proteins in the cerebrospinal fluid. A comparative study in methods

Asymptomatic neurosyphilis

Lumbar puncture was performed in 18 patients with latent syphilis to rule out asymptomatic neurosyphilis. In seven patients the CSF findings were abnormal. The parameters used in CSF were cell count, total protein, immunoglobulins (IgG, IgA, IgM), IgG index, and serologic tests for syphilis (VDRL, Kolmer, RPCF and FTA-ABS, including monospecific IgG and IgM conjugates). In three patients, the CSF findings 7-10 months after treatment are also given. Penicillin levels in serum and CSF were determined in two patients after aqueous procaine penicillin G im with and without oral probenecid. The effect of blood contamination on the differentiation between normal and abnormal CSF may not be significant.

[Cerebrospinal fluid proteins: III. Normal values of immunoglobulins G, A and M (variations related to race, sex and age)]

The literature on quantitation of immunoglobulins in normal CSF and variations of these values related to race, sex and age was reviewed. Immunoglobulins (Ig) G, A and M of normal CSF (sub-occipital puncture) of 116, 78 and 45 patients respectively, were measured by radial immunodiffusion, in order to verify variations related to race, sex and age, as well as to establish their normal limits. The results allowed us to conclude that: a) there are no differences between races with respect to the levels of IgG, A and M; b) variations related to sex or age on the CFS immunoglobulins content in children (1 to 11 years old) are not found; c) the mean IgG (mg/100 ml) level in children is lower than in adults, although the mean IgG percentage concentration in children is not different from that found in adults; the normal range for CSF IgG in children is 0.21 to 2.93 mg/100 ml; d) the mean IgA content (mg/100 ml and % of the total protein) in children are lower than in adults and in physiological conditions do not exceed 0.15 mg/100 ml (0.7% of the total protein); e) there are no differences related to sex or age with respect to the CSF levels of immunoglobulins in adults; the normal range of IgG in adults is 0.51 to 4.00 mg/100 ml; in children and adults the normal limits for the relative values of IgG are 3 to 12%; IgA is found in the CFS of adults in a concentration up to 0.32 mg/100 ml (0.9%); f) IgM is found in both children's and adults' CSF at very low levels, not exceeding 0.2 mg/100 ml (0.25%). Comparison of the results obtained in this work with those found in some publications was carried out and is briefly discussed.

[Immunoglobulins of the normal cerebrospinal fluid]

The most important methods and results found in literature on immunoglobulins of the normal cerebrospinal fluid (CSF) are reviewed. A study was made of immunoglobulins in the CSF of 50 individuals who suffered from chronic migraine but showed normal results for the physical and neurological examinations; electroencephalograph, CSF tests (sub-occipital puncture) and proteinogram of the serum also fell within the limits of normalcy in all of the 50 cases. The study of immunoglobulins was conducted through the radial immunodifusion method. Results obtained as to immunoglobulins of the CSF varied between 1,55 and 3,97 mg/100 ml, or 0,17 and 0,44 for IGG; values lay between 0 and 0,62 mg/100 ml, or 0,37 UI for IGA. Presence of IGM was not detected in any of the cases studied. Analysis of the results showed that, for the CSF of the cisterna magna in normal individuals, IGG is always found at an average concentration of 2,37 mg/100 ml and a standard deviation of 0,59. IGA is mostly found at an average concentration of 0,34 mg/100 ml and a standard deviation of 0,17. IGM is not demonstrable, under normal conditions, by the method chosen by the author.

Discrimination of elevated immunoglobulin concentrations in CSF due to inflammatory reaction of the central nervous system and blood-brain-barrier dysfunction

Inflammatory reactions of the central nervous system (CNS) are diagnosed by the determination of elevated immunoglobulin concentrations in cerebrospinal fluid (CSF) due to local production of immunoglobulins. However, unspecific disturbances of the blood-brain-barrier (BBB) can also cause an increase of CSF immunoglobulin concentration as a result of filtration from blood serum. The methods described here attempt a more precise characterization of immunoglobulins in CSF and to define that portion of CSF immunoglobulin derived from the CNS. Albumin and the immunoglobulin fractions IgG, IgA and IgM are determined in serum and CSF. The ratio of albumin in serum and CSF is taken as an indicator of BBB function. By the determination of quotients an overproportional immunoglobulin elevation in CSF as expression of an inflammatory reaction of the CNS can be detected. Methodological problems and the definition of normal ranges are discussed.