Serum-CSF protein gradients, the blood-CSF barrier and the local immune response.

For the majority of proteins there is a steady state equilbrium between the serum and the CSF compartment which depends upon the hydrodynamic radii of the passively transferred molecules. For clinical purposes the serum-CSF concentration ratios of albumin (Aalb) and alpha2-macroglobulin (Qalpha2 M) have proven to be a reliable barrier parameter, which is more sensitive than the total protein level in certain diseases, e.g. disk protrusions, degenerative processes and metabolic disorders. The immunoglobulins G and A cope with the passive transfer mechanism in both normal conditions and all degrees of pure barrier impairments but deviate in cases with local immunoglobulin production. The method described produces a quantitative differentiation between the locally synthesized and the serum-derived immunoglobulin fractions. A humoral immune response within the central nervous system was found in certain stages of acute infectious diseases and with chronic inflammatory processes such as subacute sclerosing panencephalitis, neurolues and multiple sclerosis.