Plasma cells obtained from bone marrow samples of 45 patients with MM, eight patients with MGUS, eight patients with Waldenström's macroglobulinaemia (WM), one patient with immunocytoma, and 12 controls were characterized by immunophenotyping, estimation of DNA content, and labeling index, as well as by morphological analysis. Plasma cells from 37/45 myeloma and 5/8 MGUS patients expressed CD38 and CD56 (N-CAM) on their surface but were negative for other NK cell-associated antigens such as CD16 (Fc gamma RIII) or CD2. All tumor cells of less-differentiated cell type (WM, immunocytoma) and normal polyclonal plasma cells were negative for CD56. CD56-specific mRNA was demonstrated in myeloma cells by northern blot analysis. Another adhesion molecule, ICAM-1 (CD54), was found on plasma cells from all patients and controls examined. Coexpression of CD19 (1/45), CD20 (9/45), or CD33 (3/45) was rare and CD10 with CD14 was expressed by a small tumor cell subpopulation of only one myeloma patient. The individual pattern of surface marker expression was not associated with a special-type myeloma protein isotype, stage or status of disease, LI or histological classification; however, a correlation between CD56 expression or histological classification and DNA content of the tumor cells was found.

The evaluation of thyroid autoantibodies during cytokine therapy could be a useful prognostic marker for patients with renal cell carcinoma who benefit from cytokine treatment. IL-2- and IFN-alpha2-induced tumor control and prolonged survival may require breaking of immunologic tolerance against self-antigens.

One hundred twenty-one anemic, transfusion-dependent patients with multiple myeloma (MM) or low-grade non-Hodgkin's lymphoma (NHL) were randomly allocated to receive (a) recombinant human erythropoietin (rhEPO) 10,000 U/d subcutaneously 7 days a week (fixed dose group) (n = 38), or (b) rhEPO 2,000 U/d subcutaneously for 8 weeks followed by step- wise escalation of the rhEPO dose (titration group) (n = 44), or (c) no rhEPO therapy (control group) (n = 39). The total treatment period was 24 weeks. There were no differences between the three groups with regard to baseline clinical, demographic, or health status measures. The cumulative response frequency, defined as elimination of the transfusion need in combination with an increase in the hemoglobin concentration by >20 g/L, was 60% in both rhEPO treatment groups and 24% in the control group (P = .01 and .02, respectively, log rank test). For patients in the titration group the response rate on the first dose level (2,000 U/d) was only 14%. Cox's univariate regression analysis revealed that an inadequately low endogenous erythropoietin concentration in relation to the degree of anemia and a baseline platelet concentration > or = 100 x 10(9)/L were significant predictors for response to rhEPO therapy (P < .01). Multivariate regression analysis showed that relative erythropoietin concentration was the most important factor and the platelet count had no additional influence on response. Treatment with rhEPO was well tolerated. We conclude that treatment with rhEPO may be indicated in anemic MM and NHL patients with a relative erythropoietin deficiency. An initial dose of 5,000 U/d subcutaneously may be recommended.

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