Immunoglobulin-containing cells in multiple-sclerosis plaques.

An immunoperoxidase method has been used to study the content of immunoglobulin-containing cells in 100 multiple sclerosis (M.S.) plaques and 100 adjacent areas of normally myelinated tissue obtained post mortem from ten patients with M.S. Immunoglobulin-containing cells were significantly more numerous in plaques than in non plaques and in recent plaques as compared with old plaques. More of the cells in plaques contained demonstrable light chain than heavy chain, and the kappa/lambda ratio was significantly higher in recent and moderately recent plaques than in normally myelinated tissue. 92% of the demonstrable heavy chain present in cells was IgG, 7-3% was IgA, and 0-7% IgM. It is suggested that each plaque in M.S. may be associated with local proliferation (a clone or small number of clones of immunoglobulin-producing cells, producing predominantly IgG heavy chains with kappa light chains, and occasionally with lambda light chains.