On cerebrospinal fluid immunoglobulin-G (IgG) quotients in multiple sclerosis and other diseases : A review and a new formula to estimate the amount of IgG synthesized per day by the central nervous system

Abstract

This review of the cerebrospinal fluid (CSF) changes in multiple sclerosis has brought together relevant recent advances in CSF physiology and some aspects of the pathology of MS as they relate to the CSF IgG quotients.A defense of the hypothesis that an elevated CSF IgG value in MS is the result of a basic mechanism of the CNS which does not operate normally, i.e., that IgG diffuses through the ECS of the CNS into the CSF from sites of synthesis of IgG in the CNS, but it is contained inside the blood-CNS-CSF barrier which is only accasionally slightly abnormal is presented. It is proposed that this basic mechanism underlies the elevated CSF IgG quotients (IgG/total protein and IgG/albumin); other diseases which induce the CNS to become an immunological organ, i.e., to produce IgG, are clinically infrequent and are easily differentiated on clinical grounds from MS; thus the elevated CSF IgG quotient found in over two-thirds of the cases of MS becomes of value in supporting the diagnosis of MS.Finally, a formula is presented which estimates the amount of IgG, expressed in mg, which is synthesized per day by the MS CNS. The average amount synthesized per day by a MS patient is 16 mg with a range of 0-100 mg.