Peripheral blood T lymphocytes in patients with monoclonal gammopathies: expanded subsets as depicted by capacity to bind to autologous monoclonal immunoglobulins or reactivity with anti-V gene-restricted antibodies

Clonal Cytotoxic T Cells in Myeloma

Multiple myeloma (MM) is a malignant disease characterized by accumulation of morphologically recognizable plasma cells producing immunoglobulin (Ig) in the bone marrow. The occurrence of clonal T cells in MM, as defined by the presence of rearrangements in the T-cell receptor (TCR)-beta chains detected on Southern blotting, is associated with an improved prognosis. This review aims to describe the various ways in which we have demonstrated the presence of such T cell clones, and to describe the phenotype of these cells. Finally, the specificities of these clinically important CD8+ T cell populations will be discussed in the context of immunotherapy.

T cells in myeloma

The current trend to develop immunotherapy strategies for patients with myeloma and other B cell malignancies has stimulated considerable interest in the functional state of the T cell population in these patients. Expanded clones of T cells exist in many patients with myeloma and their presence is associated with an improved survival. However, isolating T cells with tumour specificity has proven to be a difficult task and clinical immunization trials have so far failed to achieve a significant response. There is now evidence that tumour specific T cells are either tolerized or deleted following antigen presentation and that idiotype-derived, immunodominant tumour peptides may not exist in all patients. In order to develop more effective immunotherapy strategies for patients with myeloma, further studies are urgently required to identify the most appropriate tumour antigen, the nature of the interactions which take place during antigen presentation, and how to promote the cytotoxicity of autologous T cells.

B7-2–positive myeloma: incidence, clinical characteristics, prognostic significance, and implications for tumor immunotherapy

Deficiencies in B7:CD28 costimulation are considered to be one of the major causes of the failure to generate a tumor-specific immune response. Up-regulating the expression of the B7 molecules on malignant B cells has been shown to stimulate cytotoxic T cells. Plasma cells from patients with myeloma express a tumor-specific idiotype but lack CD80 (B7-1) and have a variable expression of CD86 (B7-2). This study has identified the incidence and clinical significance of high CD86 expression on plasma cells at diagnosis and studied the ability of trimeric human CD40 ligand (huCD40LT) to up-regulate the expression of the B7 family on malignant plasma cells. CD86 expression on plasma cells was increased in 54% of the patients studied at diagnosis (n = 35) and was associated with a significantly shorter survival (median, 28 versus 57 months; χ2 = 4.6;P = .03) and a higher tumor load (patients with more than 50% bone marrow plasma cells, 47% versus 6%; χ2 = 7.2; P = .005). CD86 expression was highest on immature and primitive plasma cells (CD38++, CD45+) of both patients and controls and was associated with a CD40+, CD20+, CD19−, CD138+ phenotype. The shortened survival was associated with high CD86 only on mature (CD38++, CD45−) plasma cells (χ2 = 7.6; P = .006). There was no significant correlation between high CD86 and other known prognostic markers, including serum β2-microglobulin, serum thymidine kinase, and labeling index. The addition of huCD40LT to short-term cultures up-regulated both CD80 and CD86 expression on B cells (CD19+) and CD80 on plasma cells (CD38++), but did not up-regulate CD86 expression on plasma cells. Thus, B7-2–positive myeloma consists of a subgroup of patients with a relatively poor prognosis, and CD40LT may be useful in immunotherapy protocols because it up-regulates CD80 expression on malignant plasma cells without inducing B7-2–positive myeloma.

B7-2–positive myeloma: incidence, clinical characteristics, prognostic significance, and implications for tumor immunotherapy

Deficiencies in B7:CD28 costimulation are considered to be one of the major causes of the failure to generate a tumor-specific immune response. Up-regulating the expression of the B7 molecules on malignant B cells has been shown to stimulate cytotoxic T cells. Plasma cells from patients with myeloma express a tumor-specific idiotype but lack CD80 (B7-1) and have a variable expression of CD86 (B7-2). This study has identified the incidence and clinical significance of high CD86 expression on plasma cells at diagnosis and studied the ability of trimeric human CD40 ligand (huCD40LT) to up-regulate the expression of the B7 family on malignant plasma cells. CD86 expression on plasma cells was increased in 54% of the patients studied at diagnosis (n = 35) and was associated with a significantly shorter survival (median, 28 versus 57 months; χ2 = 4.6;P = .03) and a higher tumor load (patients with more than 50% bone marrow plasma cells, 47% versus 6%; χ2 = 7.2; P = .005). CD86 expression was highest on immature and primitive plasma cells (CD38++, CD45+) of both patients and controls and was associated with a CD40+, CD20+, CD19−, CD138+ phenotype. The shortened survival was associated with high CD86 only on mature (CD38++, CD45−) plasma cells (χ2 = 7.6; P = .006). There was no significant correlation between high CD86 and other known prognostic markers, including serum β2-microglobulin, serum thymidine kinase, and labeling index. The addition of huCD40LT to short-term cultures up-regulated both CD80 and CD86 expression on B cells (CD19+) and CD80 on plasma cells (CD38++), but did not up-regulate CD86 expression on plasma cells. Thus, B7-2–positive myeloma consists of a subgroup of patients with a relatively poor prognosis, and CD40LT may be useful in immunotherapy protocols because it up-regulates CD80 expression on malignant plasma cells without inducing B7-2–positive myeloma.

Vaccination of multiple myeloma patients with idiotype-pulsed dendritic cells: immunological and clinical aspects

Multiple myeloma (MM) is characterized by a clonal proliferation of malignant plasma cells in the bone marrow secreting a monoclonal immunoglobulin (paraprotein) with specific antigenic determinants, the idiotype (Id), which can be regarded as a tumour-associated antigen (TAA). In order to analyse the impact of a dendritic cell (DC)-based vaccine, 11 patients with advanced MM were treated with CD34 stem cell-derived dendritic cells that were pulsed with Id peptides. Subsequently, the patients received three boost immunizations every other week with a combination of Id and granulocyte-macrophage colony-stimulating factor (GM-CSF) (nine patients) or with Id peptide-pulsed dendritic cells again (two patients). The treatment was well tolerated with no side-effects. The present clinical study was a proof of concept analysis of dendritic cell-based vaccines in MM. The capacity of the dendritic cells to activate idiotype-specific T cells was verified by in vitro stimulation experiments before the vaccination therapy. Immunological effects of the Id vaccination were analysed by monitoring changes in anti-idiotype antibody titres and idiotype-specific T-cell activity. After vaccination, three out of 10 analysed patients showed increased anti-idiotype antibody serum titres, indicating the induction of an idiotype-specific humoral immune response. The idiotype-specific T-cell response analysed by ELISpot was increased in four out of 10 analysed patients after vaccination, and one patient had a decreased plasma cell infiltration in the bone marrow. In conclusion, five out of 11 patients showed a biological response after vaccination. Thus, our data indicate that immunotherapy with Id-pulsed DCs in MM patients is feasible and safe. DC generated from CD34+ progenitor cells can serve as a natural adjuvant for the induction of clinically relevant humoral and cellular idiotype-specific immune responses in patients suffering from advanced MM.

Immunophenotypic and genotypic characterisation of multiple myelomas with adverse prognosis characterised by immunohistological expression of the T cell related antigen CD45RO (UCHL-1)

AIMS

To investigate whether plasma cell expression of early B cell, late B cell/preplasma cell, T cell, and myelomonocytic antigens or myeloma associated lymphocytic infiltrates correlated with prognosis in bone marrow biopsy specimens of patients with multiple myeloma.

METHODS

Bone marrow biopsy specimens of 23 patients with multiple myeloma were investigated for plasma cell expression and interstitial lymphocyte expression of T cell related antigen CD45RO (UCHL-1).

RESULTS

Eight patients showed plasma cell expression of CD45RO and 16 showed increased tumour infiltrating CD45RO positive lymphocytes, which were correlated with poor survival by multivariate analyses (p = 0.005 and p = 0.04, respectively). B cell antigens (MB2, CD20) but no T cell specific antigens (CD3) or T cell receptor gene rearrangements were expressed by plasma cells in CD45RO positive myelomas. Of 16 patients with myeloma who had increased tumour infiltrating CD45RO positive lymphocytes, four had interstitial lymphocyte expression of B cell antigens and two had interstitial lymphocyte expression of the T cell specific antigen CD3.

CONCLUSIONS

The recognition of plasma cell expression of CD45RO and increased interstitial CD45RO lymphocytes in bone marrow biopsy specimens of patients with multiple myeloma is an adverse prognostic finding not indicative of an aberrant T cell phenotype or genotype; it is consistent with B cell/pre-plasma cell antigen expression by myeloma cells and their lymphocytic precursors.

T cell repertoire in patients with multiple myeloma and monoclonal gammopathy of undetermined significance: clonal CD8+ T cell expansions are found preferentially in patients with a low tumor burden

The T cell receptor (TCR) variable (V) gene repertoire was analyzed in patients with monoclonal gammopathy of undetermined significance (MGUS) (n = 17), multiple myeloma (MM) stage I (n = 16), MM stages II/III (n = 31) and age-matched controls (n = 27) by immunofluorescence and flow cytometry using a panel of mouse monoclonal antibodies (mAb) (n = 10) against TCR V alpha and V beta gene products. T cell expansion was defined as a value > or = thrice the normal median value for each respective TCR V mAb. Fifty-three percent of all patients displayed CD8+ expansion(s) as compared to 30% of age-matched controls (p < 0.001). Within the CD4 subset, 18% of the patients displayed T cell expansion(s) in comparison to 11% of the controls (not significant). Interestingly, the CD8+ expansion(s) were more frequently noted in patients with a low tumor burden (MGUS/MMI) (73%) as compared to those with advanced disease (MM II/III) (32% and control donors (30%) (p < 0.01). Likewise, multiple CD8+ expansions (two or more) were more common in MGUS/MM I patients than in MM II/III and controls (p < 0.01). The T cell expansions were stable over time in patients with a stable disease. A high degree of clonality of the expansions was detected by TCR CDR3 fragment length analysis, determination of J beta gene usage and nucleotide sequencing. The frequent finding of oligoclonal CD8+ T cell expansions in patients with a low tumor mass, but not in patients with advanced disease justifies further work in order to identify the relevance of expanded CD8+ T cells. In one patient with T cell reactivity against the autologous myeloma idiotype, two expansions within the CD8 population (V beta 3 and V beta 5.2 respectively) displayed no reactivity against the idiotype. Instead, idiotype recognition was confined to a CD8 non-expanded V beta 22+ T cell population, with a highly restricted TCR usage (CDR3 fragment length analysis).

Prognosis in myeloma

OBJECTIVE

To review biologic factors that may be useful in determining prognosis in patients with myeloma.

DESIGN

The currently available clinical variables and staging systems were assessed for their predictive value in myeloma, and newly proposed prognostic factors were summarized.

RESULTS

Because some patients with myeloma may potentially benefit by new, more intensive therapies such as stem cell transplantation or may have prolonged survival with standard therapy, determining factors that would distinguish such patients is important. Independent prognostic factors such as the plasma cell labeling index and beta 2-microglobulin have repeatedly outperformed other prognostic clinical variables and can be combined into a system that identifies poor, intermediate, and good prognostic groups of patients with myeloma. New factors are needed to improve on the predictive value of these two variables. Studies of the biologic features of myelomas have led to the discovery of soluble interleukin 6 receptor (sIL 6R) in the serum. sIL 6R enhances the myeloma cell response to interleukin 6, a central growth factor that affects myeloma cell proliferation. Preliminary studies by the Eastern Cooperative Oncology Group show that sIL 6R predicts survival independent of the plasma cell labeling index and beta 2-microglobulin. Other proposed independent prognostic factors include cytokines and their soluble receptors, regulatory T cells, circulating myeloma cells, myeloma cell precursors, and markers of proliferation, apoptosis, and drug resistance.

CONCLUSION

Because of wide variation in duration of survival, the prognosis of patients with myeloma, a fatal bone marrow plasma cell neoplasm, cannot yet be adequately predicted. Better prognostic factors are needed for stratification in clinical trials, counseling of patients, and designing of new therapeutic trials.