The goal of immunotherapy in multiple sclerosis (MS) is to halt disease progression by correcting an immunologic abnormality. The experiments described here sought an abnormality of immunoregulation. Specifically, the immunosuppressive activity of adherent monocytes in an in vitro assay of immunoglobulin-secreting cells was tested. Although the peak response was slightly lower, the induction, development and shutdown of the response by MS cells reproduced that of control cells. Most importantly, adherent monocytes from patients with MS exerted the same maximal suppression as did monocytes from controls. Further experiments are required to determine if the adherent monocyte is an appropriate target for immunotherapy in MS.