SELECTION OF PATIENTS WITH MONOCLONAL GRAMMOPATHY OF UNDETERMINED SIGNIFICANCE IS MANDATORY FOR A RELIABLE USE OF INTERLEUKIN-6 AND OTHER NONSPECIFIC MULTIPLE-MYELOMA SERUM MARKERS

Serum levels of various immunochemical markers of clinical interest, a s interleukin-6 (IL-6), C-reactive protein (CRP) and beta(2)-microglob ulin (beta(2)M), were measured in sera from 98 subjects affected with monoclonal gammopathy of undetermined significance (MGUS; 80% of which bearing cancer too) and from 39 patients with multiple myeloma (MM). In addition, the ratio between serum IgG/IgA amounts (GAR) was also ca lculated in monoclonal gammopathies of IgG type. Consistent with our p revious investigations, we found that tumor presence significantly inf luenced the serum levels of the various markers (except GAR) in MGUS p atients; in fact, only when comparing MGUS without tumor and MM patien ts, was a clear difference observed for all markers considered. The da ta presented discourage the use of IL-6, CRP and beta(2)M as discrimin ant indices between MGUS and MM patients, unless a careful selection o f MGUS subjects is performed. Further investigations on these potentia l markers are therefore needed for a more rational clinical applicatio n.