Monoclonal IgM K antibody precipitating with chondroitin sulfate C from patients with axonal polyneuropathy and epidermolysis

Abstract
We studied two patients with an axonal type of polyneuropathy, epidermolysis, and IgMK plasma cell dyscrasia. The IgMK was deposited in the dermis, was absorbed from the serum by axonal micelle preparations, and was precipitated with chondroitin sulfate in highly purified agarose in 0.15 M NaCl with 0.01 M phosphate buffer, pH 7.8. In contrast, we found none of these abnormalities in three patients with IgM plasma cell dyscrasia and demyelinating neuropathy. Of 78 other macroglobulinemic serum samples from patients without neuropathy, 7 precipitated with a sulfated polysaccharide. This reaction occurred at low ionic strength, 0.05 M barbital buffer, pH 8.1, but did not occur in the higher ionic strength of 0.01 M phosphate with 0.15 M NaCl (PBS). The interaction of the IgM with chondroitin sulfate at relatively high ionic strength could cause both the axonal polyneuropathy and the epidermolysis.