title: Cytobiological studies in multiple myeloma.
abstract: Multiple myeloma (MM) is a heterogeneous disease in which the median survival time varies from a few months to more than 10 years. Clinical, kinetic, and immunological studies reflected such a heterogeneity. In clinical studies beta 2-microglobulin (beta 2-M), which is a well-known prognostic factor, was evaluated as an expression of tumor burden: a linear increase has been observed from stage I to stage III. No clear cutoff was detected between monoclonal gammopathy of undetermined significance (MGUS) and stage I MM. Kinetic studies have been performed by 3[H]thymidine or 5-bromo-2-deoxyuridine incorporation in bone marrow plasma cells. An analysis has been carried out between beta 2-M and the labeling index (LI). No correlation has been observed between these 2 parameters which identify different subgroups of poor prognosis patients. MGUS always showed an LI less than 1% allowing a clear distinction from stage I MM. A reduced survival time has been observed in patients with an LI greater than 2%. A subgroup of MM patients characterized by an LI greater than 2% and a decrease of M component greater than 50% within 3 months (early responders) has been identified. These patients showed a median survival time of about 10 months. Immunological studies identified a sharp decrease of 5' nucleotidase (5'NT) enzymatic activity in peripheral blood lymphocytes. This enzymatic defect is the biochemical marker of the expansion of a T subpopulation expressing low levels of 5'NT. This subpopulation was characterized by monoclonal antibodies and is represented by activated suppressor cells (OKM1+, DR+). Such an unbalancement in the T cell subpopulation was evident in poor prognosis patients. Clinical, kinetic and immunological studies identified new prognostic parameters that will be useful in the future therapeutic strategy of MM.
authors.affiliation: Cattedra di Ematologia, Università di Torino, Italia.
authors.forename: A
authors.initials: A
authors.lastname: Pileri
authors.forename: M
authors.initials: M
authors.lastname: Massaia
authors.forename: U
authors.initials: U
authors.lastname: Dianzani
authors.forename: P
authors.initials: P
authors.lastname: Omedè
authors.forename: M
authors.initials: M
authors.lastname: Boccadoro
mesh_terms: D015720:5'-Nucleotidase; D003937:Diagnosis, Differential; D006801:Humans; D008940:Mitotic Index; D009101:Multiple Myeloma / Q000032:analysis / Q000175:diagnosis / Q000473:pathology*; D009363:Neoplasm Proteins / Q000032:analysis; D009708:Nucleotidases / Q000032:analysis; D010265:Paraproteinemias / Q000175:diagnosis; D011379:Prognosis; D013601:T-Lymphocytes / Q000145:classification; D001613:beta 2-Microglobulin / Q000032:analysis
chemical_list: D009363:Neoplasm Proteins; D001613:beta 2-Microglobulin; D009708:Nucleotidases; D015720:5'-Nucleotidase