[Benign monoclonal gammopathies: probable antibody specificity of monoclonal immunoglobulins]

40 patients with benign paraproteinemia have been studied in relation to their age and associated diseases. Significantly high frequency of liver diseases (CALD, cirrhosis, hepatoma, metastases) has been found (12 over 40 people) and increased incidence of idiopathic paraproteinaemia in the old age has been confirmed. 9 patients have been followed for 5 years, so that one could be sure that they had really benign paraproteinaemia: these patients have been then studied from an immunological point of view, in vivo by means of skin tests (PPD, Candida, Trichophyton, DNCB) and in vitro by searching for circulating immune complexes (using a new highly specific immuno-enzymatic method), and compared to controls without paraproteinaemia. Highly positive skin tests have been found only in 7 over 9 patients (even in old subjects) and 6 of them had circulating immune complexes (C.I.C.) in their sera; all the controls were negative both for skin tests and for C.I.C. Immune complexes have been found also in some cases of idiopathic paraproteinaemia, so that they do not seem to be in relation to the associated diseases. The Authors suggest that a genetically determined defect in regulator/suppressor T lymphocyte activity may cause the growth of a benign B cell neoplasm; and that monoclonal immunoglobulins most probably have antibody specificity and are directed against target antigens.