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. A correlation 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 the true for IgA. The Protein-A plaque method, adopted for 20 X 10(3) 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.