Susanne Bergenbrant

Modulation of anti-idiotypic immune response by immunization with the autologous M-component protein in multiple myeloma patients.

Multiple myeloma is characterized by a proliferation of clonal B lymphocytes and plasma cells. The idiotypic structure of clonal immunoglobulin (Ig) expressed on the tumour B‐cell surface can be regarded as a tumour‐specific antigen and, as such, a potential target for anti‐idiotypic T and B cells in an immune regulation of the tumour‐cell clone. Active immunization using the autologous monoclonal Ig as a ‘vaccine’ was shown to induce tumour‐specific immunity in murine B‐cell tumours and in human B‐cell lymphoma. With the aim to induce or amplify an anti‐idiotypic response in multiple myeloma, five stage I–III patients were repeatedly immunized with the autologous monoclonal IgG. Induction of idiotype‐specific cellular immunity was analysed in vitro by an enzyme‐linked immunospot assay (interferon‐γ and interleukin‐4 secreting cells). B cells secreting anti‐idiotypic IgM antibodies were also analysed. An anti‐idiotypic T‐cell response was amplified 1.9–5‐fold in three of the five patients during immunization. The number of B cells secreting anti‐idiotypic antibodies also increased in these three patients. In two of the patients induction of idiotype‐specific immunity was associated with a gradual decrease of blood CD19+ B cells. The induced T‐cell response was eliminated during repeated immunization. Further studies are warranted to optimize the immunization schedule in order to achieve a long‐lasting T‐cell immunity against idiotypic determinants on the tumour clone. A role for immunity in controlling the tumour clone remains to be established.

Idiotype‐specific T cells in multiple myeloma stage I: an evaluation by four different functional tests

Idiotype-specific T cells were characterized in patients with multiple myeloma stage I by analysing idiotype-induced DNA synthesis (3H-thymidine incorporation), IL-2 and IFN-gamma production at the single cell level (ELISPOT) (in vitro tests) and delayed type hypersensitivity (DTH) skin reaction (in vivo test). In seven out of eight patients at least one of the four tests was positive. In five patients three or more tests were positive. One patient was negative in all four tests. Six patients had both IL-2 and IFN-gamma-secreting cells and three of them also a DTH response. Furthermore, those three patients with a proliferative response also had IL-2 and IFN-gamma-secreting cells induced by the idiotype. The data indicate that part of the idiotype-specific T cell fraction belongs to the CD4 Th1 cell population. Whether CD8-specific T cells also were present could not be ruled out. The present study provides further support for the existence of idiotype-specific T cells in multiple myeloma. Such cells might be an important target for an immune-mediated therapeutic approach.

Interleukin 6, tumour necrosis factor α, interleukin 1β and interleukin 1 receptor antagonist promoter or coding gene polymorphisms in multiple myeloma

Proinflammatory cytokines such as interleukin 6 (IL‐6), tumour necrosis factor α (TNF‐α) and IL‐1β are considered to be involved in the pathogenesis of multiple myeloma (MM). In the present study, we examined a G/C polymorphism at position −174 in the promoter region of IL‐6, a biallelic polymorphism at position −308 in the promoter region of TNF‐α, the TaqI restriction fragment length polymorphism in exon 5 of IL‐1β and a variable number of identical tandem repeat polymorphisms in intron 2 of IL‐1 receptor antagonist (IL‐1Ra) genes. The alleles of these loci are known to influence the level of production of the cytokines and the IL‐1Ra. Seventy‐three patients with MM, 27 with monoclonal gammopathy of undetermined significance (MGUS) and 129 healthy individuals were included. No difference was found between patients and healthy controls or between MM and MGUS patients in the distributions of genotypes and frequencies of alleles of the IL‐6 (−174), TNF‐α (−308), IL‐1βTaqI and IL‐1Ra gene polymorphisms. No associations between the polymorphisms at the loci under study and clinical factors such as age, sex, clinical stage at onset and M‐protein type were observed. Our results indicate that the cytokine (IL‐6, TNF‐α and IL‐1β) and IL‐Ra gene polymorphisms do not confer susceptibility to the development of MM.

Telomerase activity in plasma cell dyscrasias

Activation of telomerase is essential for in vitro cellular immortalization and tumorigenesis. In the present study, we investigated telomerase activation and its implications in plasma cell dyscrasias including monoclonal gammopathy of undetermined significance (MGUS), multiple myeloma (MM) and plasma cell leukaemia (PCL). All 5 patients with MGUS exhibited normal levels of telomerase activity in their plasma cells. Elevated telomerase activity was found in the samples from 21/27 patients with MM and 4/4 with PCL. In addition, 4 myeloma cell lines all expressed high levels of telomerase activity. The expression of telomerase reverse transcriptase (hTERT) and telomerase RNA template (hTER) was positively associated with the levels of telomerase activity in MM/PCL. Tankyrase expression was upregulated, concomitant with the induction of hTERT and activation of telomerase in MM/PCL. The present findings indicate that MGUS cells may not be immortalized and that activation of telomerase plays a role in the malignant transformation from MGUS to MM.

Anti-idiotypic T-cell activation in multiple myeloma induced by M- component fragments presented by dendritic cells

The monoclonal immunoglobulin (Ig) (M‐component) secreted by the tumour plasma cells in multiple myeloma (MM) has specific antigenic determinants (idiotypes; id) that can serve as tumour‐specific antigens. The intact Ig molecule is a weak antigen, and small fragments of id protein might be more immunogenic for the induction of id‐specific immunity. Dendritic cells (DC) have attracted attention as the most efficient antigen‐presenting cells and promising adjuvants for immunotherapy in tumours. In this study the in vitro T‐cell response against F(ab′)2 and Fab fragments, heavy and light chains of the M‐component was examined in five patients with MM clinical stage I. All fragments were able to stimulate T cells but F(ab′)2 or Fab fragments and heavy chains induced a stronger response than light chains. DC induced a significantly stronger id‐specific immune response than monocytes. Moreover, with DC as antigen‐presenting cells, a predominant interferon (IFN)‐γ (type‐1 T‐cell) response was seen in all patients. Both IFN‐γ and interleukin (IL)‐4 (type‐1 and type‐2 T‐cell) responses were noted when monocytes were used. Our study suggests that DC pulsed with idiotypic fragments such as F(ab′)2 fragment and heavy chain can be used for the induction of type‐1 anti‐idiotypic T‐cell response for immunotherapy in MM.

Anti-idiotypic antibodies in patients with monoclonal gammopathies: relation to the tumour load

Summary The production of anti‐idiotypic antibodies from Epstein‐Barr virus transformed peripheral blood lymphocytes was analysed in 12 patients with multiple myeloma and monoclonal gammopathy of undetermined significance. A low anti‐idiotype production was found in patients with advanced disease (multiple myeloma stage III), whereas the production was high in patients with multiple myeloma stage I and monoclonal gammopathy of undetermined significance (MGUS) (P<0·01). The study supports the existence of an immunological network response in patients with monoclonal gammopathies.

Generation of T cell clones binding F(ab′)2 fragments of the idiotypic immunoglobulin in patients with monoclonal gammopathy

SummaryLymphocytes from two patients with multiple myeloma stage I and one patient with monoclonal gammopathy of undetermined significance were found to proliferate specifically in response to low concentrations of F(ab′)2 fragments of the autologous M component. T cell clones isolated from repeatedly stimulated cultures bound specifically the autologous idiotype and proliferated after addition of soluble idiotype and exogenous interleukin-2. The majority of clones were CD8+ and showed negligible staining for CD4. Idiotype-binding clones could not be isolated from cultures of lymphocytes from a healthy control stimulated under the same conditions. The study provides support for the existence of idiotype-reactive T cells in monoclonal gammopathies. Such cells might have a regulatory role on the tumour cell clone and may be important for a future therapeutic approach.