Despite improved outcomes in multiple myeloma (MM), a cure remains elusive. However, even before the current therapeutic era, 5% of patients survived >10 years and we propose that immune factors contribute to this longer survival. We identified patients attending our clinic, who had survived >10 years (n=20) and analysed their blood for the presence of T-cell clones, T-regulatory cells (Tregs) and T helper 17 (Th17) cells. These results were compared with MM patients with shorter follow-up and age-matched healthy control donors. The frequency of cytotoxic T-cell clonal expansions in patients with <10 years follow-up (MM patients) was 54% (n=144), whereas it was 100% (n=19/19) in the long-survivors (LTS-MM). T-cell clones from MM patients proliferated poorly in vitro, whereas those from LTS-MM patients proliferated readily (median proliferations 6.1% and 61.5%, respectively (P<0.0001)). In addition, we found significantly higher Th17 cells and lower Tregs in the LTS-MM group when compared with the MM group. These results indicate that long-term survival in MM is associated with a distinct immunological profile, which is consistent with decreased immune suppression.

We have characterised the CD138⁻ PCs as more immature and with a significantly higher proliferative potential. The current trend to ignore this more immature and proliferative subpopulation of malignant PCs may have serious implications when determining gene expression, classifications and drug sensitivity of the malignancy.

Discrepancies in the literature between regulatory T cell (T reg ) and pro-infl ammatory T helper 17 (T h17 ) numbers in multiple myeloma (MM) can be largely explained by technical diff erences in methodology and patient selection. In this study, T reg cells were defi ned as CD3 ؉ CD4 ؉ CD25 ؉ ؉ CD127 lo cells. Patients with MM ( n ‫؍‬ 20) had a signifi cant imbalance in T reg /T h17 ratio when compared with either aged-matched controls ( n ‫؍‬ 28) or other monoclonal gammopathies, and this was associated with a signifi cantly worse survival. The percent T reg in bone marrow of patients with MM was higher than that in matched peripheral blood samples ( p ‫؍‬ 0.02), although FOXP3 expression within bone marrow T cells was lower ( p ‫؍‬ 0.02). We observed increased T reg function, both in vivo and in vitro , due at least partially to an increase in CTLA-4 expression by concurrent treatment with dexamethasone and immune modulatory compounds (iMiDs). We suggest that immunoregulatory balance is important during active chemotherapy and that conclusions related to the immunostimulatory eff ect of iMiDs based on in vitro testing must be considered with caution.

The expanded T cell clones are associated with a prolonged survival in patients with multiple myeloma. We sought to confirm this prognostic significance in a multicenter patient cohort and investigate the effect of thalidomide on clones and T regulatory cells (T(regs)). Blood was collected from 120 patients enrolled in a Phase III trial of maintenance therapy +/- thalidomide after autologous stem cell transplantation. TCR Vbeta repertoire analysis identified T cell expansions in 48% of patients pre-transplant and 68% after 8-month maintenance. T cell expansions, previously shown to be clonal, were predominantly CD8+ (93%) and all 24 TCR Vbeta families tested were represented. Thalidomide therapy was associated with a significant increase in the incidence of patients with multiple expansions (49% vs. 23%; chi2 = 6.8; p = 0.01). The presence of expansions regardless of therapy was associated with a significantly longer median progression free survival (PFS) (32.1 vs. 17.6 months; chi2 = 5.6; p = 0.02) and overall survival (OS) (chi2 = 3.9; p < 0.05). Median PFS in the thalidomide arm was 50.9 months for patients with expansions and 28.3 months for patients without expansions (chi2 = 19.4; p = 0.0002). Thalidomide did not appear to modulate T(reg) numbers. Expanded T cell clones are prognostically significant and have an impact on progression after thalidomide therapy in a proportion of patients.

T cells contribute to host-tumor interactions in patients with monoclonal gammopathies. Expansions of CD8(+)CD57(+) T-cell receptor Vbeta-positive (TCRVbeta(+))-restricted cytotoxic T-cell (CTL) clones are found in 48% of patients with multiple myeloma and confer a favorable prognosis. We now report that CTL clones with varying TCRVbeta repertoire are present in 70% of patients with Waldenström macroglobulinemia (WM; n = 20). Previous nucleoside analog (NA) therapy, associated with increased incidence of transformation to aggressive lymphoma, significantly influenced the presence of TCRVbeta expansions (chi(2) = 11.6; P < .001), as 83% of patients without (n = 6) and only 7% with (n = 14) TCRVbeta expansions had received NA. Clonality of CD3(+)CD8(+)CD57(+)TCRVbeta(+)-restricted CTLs was confirmed by TCRVbeta CDR3 size analysis and direct sequencing. The differential expression of CD3(+)CD8(+)CD57(+)TCRVbeta(+) cells was profiled using DNA microarrays and validated at mRNA and protein level. By gene set enrichment analysis, CTL clones expressed not only genes from cytotoxic pathways (GZMB, PRF1, FGFBP2) but also genes that suppress apoptosis, inhibit proliferation, arrest cell-cycle G1/S transition, and activate T cells (RAS, CSK, and TOB pathways). Proliferation tracking after stimulation confirmed their anergic state. Our studies demonstrate the incidence, NA sensitivity, and nature of clonal CTLs in WM and highlight mechanisms that cause anergy in these cells.

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The DiaMed gel card screening assays are appropriate screening tools for the investigation of transfusion-related anaphylactic reactions and can be used in any routine blood bank laboratory.

Trogocytosis is the transfer of cell membrane material from one cell to another during short term cell-cell contact. Recent studies have suggested that the transfer of cell membrane patches across the immunological synapse is at least partly responsible for immune tolerance, tumor escape and the production of adaptive T regulatory cells (Tregs). We sought to identify the extent of tumor-related trogocytosis in patients with multiple myeloma and have developed an in vitro model for further study. Trogocytosis in patients with multiple myeloma was demonstrated by flow cytometry, immunohistochemistry, confocal microscopy, lack of mRNA expression and by the failure to upregulate costimulatory molecules in vitro after stimulation by IL2 and huCD40LT. Of the costimulatory molecules CD80, CD86, B7-H1, B7-H3 and PD-L2, only CD80 and CD86 showed significant transfer to T cells. Increased CD80 expression was found on the T cells of 9% of patients and CD86 on 13% of patients (n= 95). Both CD4 and CD8 memory (CD45RO+) cells were involved but not naïve T cells (CD45RA+). HLA-G expression was found on less than 1% of T cells in 69/70 different myeloma blood samples. Following biotinylation of plasma cells (CD38++) using an in vitro culture model, trogocytosis was demonstrated in up to 36% of T cells. The presence of trogocytosis on CD3- TCRαβ-mutant Jurkat cells (J.RT3-T3.3) and on normal T cells with HLA incompatibility infers that trogocytosis is independent of immune recognition and TCR engagement. In vitro stimulation with IL-2 and huCD40LT and mRNA studies showed that T cells acquire CD80 and CD86 cell surface antigen but unlike B cells do not produce CD80 and CD86 mRNA (n=5) and cannot be stimulated to express CD80 and CD86 (n=6). Trogocytosis was not evident in age-matched control lymphocytes but could be induced in normal lymphocytes in vitro after exposure to malignant plasma cells. Trogocytosis is common in patients with multiple myeloma and involves the transfer of costimulatory molecules and other cell membrane proteins from malignant plasma cells to T cells. Tumor-induced trogocytosis may be a common cause of the failure of cytotoxic T cells and provide a mechanism of tumor escape.