Limited response to idiotype vaccination in patients with myeloma suggests that there is a need to develop better immunotherapy strategies. It has been determined that the number of high-potency CMRF44 ؉ CD14 ؊ CD19 ؊ dendritic cells (DCs) in the blood of patients with myeloma (range, 0.03%-0.8% of mononuclear cells [MNCs]; n ‫؍‬ 26) was not significantly different from that in controls (range, 0.05%-0.8% of MNCs; n ‫؍‬ 13). Expression of the costimulatory molecules CD80 and CD86 on DCs from these patients (mean, 29%؎17% of MNCs and 85%؎10% of MNCs, respectively) was also normal (mean, 29%؎17% and 86%؎16% of MNCs, respectively). Up-regulation of CD80 expression in response to stimulation by human (hu)CD40LT ؉ interleukin (IL)-2 was significantly reduced on the DCs of patients with myeloma during stable disease (n ‫؍‬ 9) and was absent during progressive stages (n ‫؍‬ 7) of disease. Similar effects were seen on B cells but not on monocytes of the same group of patients. CD86 expression on DCs was high before (86%) and after (89%)

Summary. The presence of T-cell clones in peripheral blood has been previously shown to be associated with a survival advantage in patients with multiple myeloma and suggests that the expanded T-cell populations may be involved in an anti-tumour response. We studied the T-cell receptor (TCR) repertoire of 38 patients with myeloma to identify and characterize the expanded T-cell populations by flow cytometry. T-cell expansions were found in 79% of the patients. The expansions occurred randomly among the 21 variable regions of the TCR b chain (Vb) studied, representing 62% of the V-b repertoire, and were stable during an 18-month follow-up. The phenotype of the expanded V-b populations was predominantly CD8 1 , CD57 1 , CD28 2 and perforin 1 , which differed significantly from the other nonexpanded Vb populations. The expression of the apoptosis markers Fas (CD95) and bcl-2 were similar between the expanded and non-expanded Vb populations. In conclusion, expanded T-cell populations were frequent in patients with myeloma, they remained unchanged during follow-up and had phenotypic characteristics of cytotoxic T cells. These data add further support to the concept that the T-cell expansions may have an immunoregulatory role in myeloma.

Summary The c-myc oncogene has been extensively implicated in cell proliferation, cell differentiation and programmed cell death. Aberrant expression of the c-myc gene product has been observed in a range of tumours and has also been implicated in cisplatin (cis-dichlorodiammineplatinum)-mediated chemoresistance. A solid transplantable tumour model in syngeneic DA rats was subjected to treatment with cisplatin to determine the impact of such therapy on endogenous c-myc gene expression. Serially