Link between peripheral neuropathy and monoclonal dysglobulinemia: a study of 66 cases

The association of peripheral neuropathy (PN) and monoclonal dysglobulinemia has often been reported, although a direct link between the two is not readily established. Linkage is generally based on consideration of the clinical, electrophysiological and immunological findings along with details of the course. We report here a study of 66 of our own cases which benefitted from immunological and immunopathological analyses of serum. In 62 of these cases, histological and immunopathological examinations of nerve biopsy specimens were realized. Such a discussion about a link between the dysglobulinemia and the peripheral neuropathy is of clinical interest as it provides information for decisions about the continuation of potentially neurotoxic chemotherapy. In this prospective study conducted on a case by case basis, the origin of the neuropathy, whether due to the chemotherapy, the dysimmune process, the presence of abnormal immunoglobulins in the nerve, amyloid deposits, infiltration of nerve parenchyme by abnormal cells, or a combination of one or more of these mechanisms, could be determined in most cases. We divided our population of 66 patients into 4 etiological groups: group 1: direct link (56.1%), group 2: indirect link (12.7%), group 3: no link (10.6%), group 4: doubtful link (21.2%). In group 1 we found a statistically significant association between the peripheral neuropathy and an IgM kappa MGUS.