Les sous-classes d’IgG dans le LCR présentent-elles un réel intérêt ?

Abstract

AbstractSerum total IgG measurement is a common lab act in medical biology. More specialized, serum IgG subclasses measurement plays a key role in IgG4-Re- lated Disease but is also useful for second-line diagnosis in humoral immune deficiencies. In the cerebrospinal fluid (CSF), an index is used as an indicator of the relative amount of CSF IgG compared to serum. Any increase in the index reflects IgG production in the central nervous system. Regarding IgG subclasses in the CSF, medical laboratories are now getting demands, actually to find out if there is any IgG4 subclass. These IgG4 in CSF could be associated with IgG4-related hypertrophic pachymeningitis but without appropriate studies corroborating this, their measurement should be done only when tissue biopsy cannot be performed. Quantitative measurement on serum is validated with nephelometry and turbidimetry assays. Each laboratory has to validate the assays on CSF before giving results. In this mini review, we present the indications of total IgG and IgG subclasses on serum as well as the benefit of IgG subclasses in CSF and the techniques available in a medical laboratory.