[Gammopathies with oligoclonal electrophoretic patterns. Incidence, immunochemical nature and association with neoplastic pathology].

Electrophoretic study of 680 cases of human sera containing monoclonal bands showed an oligoclonal pattern in 92 cases (13.5%). Immunoelectrophoretic analysis of 52 oligoclonal cases showed various patterns: polyclonal in 12 cases, monoclonal in 23 cases, monoclonal with associated Bence Jones proteinemia in four cases, and biclonal in only 13 cases. In cases lacking immunoelectrophoretic evidence for the oligoclonal nature of gammopathy, a restricted heterogeneity in molecular weight of subunits was evidenced in 12 out of 27 cases. Associated diseases were investigated comparatively in the monoclonal and the oligoclonal groups. A significant increase in cancer aetiology was found in the oligoclonal group (p less than 0.0005).