Immunoglobulin-producing cells in CSF and blood from patients with multiple sclerosis and other inflammatory neurological diseases enumerated by Protein-A plaque assay

Using the Protein-A plaque assay, numbers of IgG + IgA + IgM producing cells determined in patients with multiple sclerosis (MS) were 0.1–5% in CSF and 0.1–0.7% in peripheral blood; interestingly, 7 of 11 MS patients had IgM producing cells in CSF. In patients with aseptic meningitis (AM), the corresponding values were 0.04–7.5% in CSF and 0.4–2.4% in peripheral blood. There were more Ig producing cells in peripheral blood from patients with AM and MS than in healthy subjects. cocorrelation between numbers of IgG producing cells in CSF and the concentrations of intrathecally produced IgG (CSF IgG index) was registered in patients with AM: the same was true for IgA. The Protein-A plaque method, adopted for 20 × 10³ lymphocytes, makes possible enumeration of Ig-producing cells in CSF and discrimination among cells secreting different Ig classes, thereby being a powerful tool for studying immune reactions in the CNS-CSF compartment.