PB2107 UPREGULATION OF PD-1 CHECKPOINT RECEPTOR MOLECULE ON BONE MARROW T-CELLS FROM PATIENTS WITH MULTIPLE MYELOMA, AND ITS POTENTIAL IMPACT ON CLINICAL OUTCOME

BackgroundMarrow infiltrating lymphocytes (MILsTM) are the product of activating and expanding bone marrow T cells.1 The bone marrow is a specialized niche in the immune system enriched for antigen-experienced, memory T cells. In patients with multiple myeloma and other hematological malignancies that relapse post-transplant, MILs have been shown to contain tumor antigen-specific T cells and adoptive cell therapy (ACT) using MILs has demonstrated antitumor activity.2 3 The bone marrow has been shown to harbor tumor-antigen specific T cells in patients with melanoma,4 5 glioblastoma,6 breast,7 non-small-cell lung8 and pancreatic cancers.9 Here, we sought to determine if tumor-specific MILs could be expanded from the bone marrow of patients with a range of different solid tumors.MethodsBone marrow and blood samples were collected from patients with advanced and metastatic cancers. To date, samples have been collected from a minimum of four patients with non-small cell lung cancer (NSCLC), prostate cancer, head and neck cancer, glioblastoma, and breast cancer. Samples from patients with multiple myeloma were used as a reference control. Utilizing a 10-day proprietary process, MILs and peripheral blood lymphocytes (PBLs) were activated and expanded from patient bone marrow and blood samples, respectively. T cell lineage-specific markers (CD3, CD4 and CD8) were characterized by flow cytometry pre- and post-expansion.Tumor-specific T cells were quantitated in expanded MILs and PBLs using a previously described cytokine-secretion assay [2]. Briefly, autologous antigen-presenting cells (APCs) were pulsed with lysates from allogeneic cancer cell lines and co-cultured with activated MILs or PBLs. APCs pulsed with irrelevant mis-matched cancer cell line lysates or media alone were used as negative controls. Tumor-specific T cells were defined as the IFNgamma-producing population by flow cytometry.ResultsMILs were successfully expanded from all patient bone marrow samples tested, regardless of tumor type. Cytokine-producing tumor-specific CD4+ and CD8+ T cells were detected in each of the expanded MILs. In contrast, tumor-specific T cells were not detected in any of the matched activated and expanded PBLs.ConclusionsMILs have been successfully grown for all solid tumor types evaluated, including NSCLC, prostate, head and neck, glioblastoma and breast cancer. Clinical studies have been completed in patients with multiple myeloma and other hematological cancers. 2 3 A phase IIa trial to evaluate MILs in combination with a checkpoint inhibitor is underway in patients with anti-PD1/PDL1-refractory NSCLC (ClinicalTrials.gov Identifier: NCT04069936). The preclinical data presented herein demonstrate that expanding MILs is feasible. MILs-based therapies hold therapeutic promise across a wide range of tumor indications.Ethics ApprovalThis study was approved by each participating instituion’s IRB.ReferencesBorrello I and Noonan KA. Marrow-Infiltrating Lymphocytes - Role in Biology and Cancer Therapy. Front Immunol 2016 March 30; 7(112)Noonan KA, Huff CA, Davis J, et al. Adoptive transfer of activated marrow-infiltrating lymphocytes induces measurable antitumor immunity in the bone marrow in multiple myeloma. Sci. Transl. Med 2015;7:288ra78.Biavati L, Noonan K, Luznik L, Borrello I. Activated allogeneic donor-derived marrow-infiltrating lymphocytes display measurable in vitro antitumor activity. J Immunother 2019 Apr;42(3):73–80.Müller-Berghaus J, Ehlert K, Ugurel S, et al. Melanoma-reactive T cells in the bone marrow of melanoma patients: association with disease stage and disease duration. Cancer Res 2006;66(12):5997–6001.Letsch A, Keilholz U, Assfalg G, et al., Bone marrow contains melanoma-reactive CD8+ effector T Cells and, compared with peripheral blood, enriched numbers of melanoma-reactive CD8+ memory T cells. Cancer Res 2003 Sep 1;63(17):5582–5586.Chongsathidkiet P, Jackson C, Koyama S, et al., Sequestration of T cells in bone marrow in the setting of glioblastoma and other intracranial tumors. Nature Medicine 2018 Aug 13; 24:1459–1468.Feuerer M, Rocha M, Bai L, et al. Enrichment of memory T cells and other profound immunological changes in the bone marrow from untreated breast cancer patients. Int J Cancer 2001; 92(1):96–105.Safi S, Yamauchi Y, Stamova S, et al. Bone marrow expands the repertoire of functional T cells targeting tumor-associated antigens in patients with resectable non-small-cell lung cancer. Oncoimmunology 2019;8(12):e1671762.Schmitz-Winnenthal FH, Volk C, Z’Graggen K, et al. High frequencies of functional tumor-reactive T cells in bone marrow and blood of pancreatic cancer patients. Cancer Res 2005;65(21):10079–87.

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Abstract 1887: Anti-CD38/CD28xCD3 trispecific T cell engager induces proliferation of primary T cells and mediates potent killing of primary malignant plasma cells isolated from Multiple Myeloma bone marrow aspirates

10.1158/1538-7445.am2021-1887 ◽

2021 ◽

Author(s):

Nizar El-Murr ◽

Sahar Kassem ◽

Nadège Carrié ◽

Christophe Henry ◽

Angela Virone-Oddos ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

T Cell ◽

Plasma Cells

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941 Stromal cell sialylation suppresses T cells in inflammatory tumour microenvironments: a new tumour stromal cell immune checkpoint?

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.941 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A987-A987

Author(s):

Oliver Treacy ◽

Hannah Egan ◽

Kevin Lynch ◽

Niamh Leonard ◽

Kim De Veirman ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

Sialic Acid ◽

Stromal Cells ◽

Stromal Cell ◽

Immune Cell ◽

Healthy Human ◽

Human Donor ◽

Healthy Human Donor

BackgroundImmunosuppressive tumour microenvironments (TME) reduce the effectiveness of immune responses in cancer. Non-haematopoietic mesenchymal stromal cells, precursors to cancer-associated fibroblasts (CAFs), dictate tumour progression by enhancing immune cell suppression. Sialic acids, which exist as terminal sugars of glycans (known as sialoglycans), are highly expressed on cancer cells and hyper-sialylation of glycans is known to promote immune evasion in cancer. Sialoglycans are recognized by sialic acid-binding immunoglobulin-like lectins (Siglecs), a family of immunomodulatory receptors, which are analogous to the immune checkpoint inhibitor PD-1.1 The role of sialyation in stromal cell-mediated immunosuppression, however, is unknown. Using models of solid (colorectal cancer - CRC) and haematological (multiple myeloma - MM) stromal-rich tumours in both mouse and human, the aim of this study was to investigate if stromal cell sialylation contributes to enhanced immunosuppression in the TME.MethodsFlow cytometric analysis of sialic acid expression was performed initially on bone marrow-derived stromal cells isolated from healthy human donor bone marrow aspirates, from wild-type Balb/c mice or from 5T33 multiple myeloma mice. Stromal cells were also isolated and expanded from colorectal cancer patient tumour biopsies (CAFs) with matched controls isolated from tumour-adjacent non-cancerous tissue (normal-associated fibroblasts - NAFs) or from whole blood from primary multiple myeloma bone aspirates. Informed consent was obtained from all patients prior to sampling. Immunosuppression assays were performed using these stromal cells with or without exposure to the tumour cell secretome from the mouse and human CRC cell lines CT26 or HCT116 and HT29, respectively, co-cultured with either murine lymphocytes or healthy human donor-derived peripheral blood mononuclear cells (PBMCs).ResultsOur results showed that tumour conditioned stromal cells have increased levels of sialyltransferase gene expression, α2,3/α2,6-linked sialic acid and Siglec ligands. Co-culture assays revealed that CAFs induced significantly higher frequencies of Siglec 7 and Siglec 9-expressing CD8 T cells, as well as Tim-3 and PD-1-expressing CD8 T cells, compared to NAFs. Inhibition of sialyltransferase activity using the inhibitor 3FAXNeu5Ac reversed these CAF-induced effects. Interestingly, sialyltransferase inhibition had no observed effects on T cells co-cultured with NAFs.ConclusionsThese results demonstrate that targeting stromal cell sialylation can reverse immune cell suppression and reactivate exhausted T cells. These novel data support a rationale for the assessment of stromal cell sialylation and Siglec ligand expression in order to better stratify patients for immunotherapeutic combination treatments that aim to reactivate exhausted T cells in stromal-enriched tumour microenvironments.AcknowledgementsThe authors would like to thank the Blood Cancer Network of Ireland Biobank for providing bone marrow aspirates.ReferenceGray MA, Stanczak MA, Mantuano NR, Xiao H, Pijnenborg JFA, Malaker SA, Miller CL, Weidenbacher PA, Tanzo JT, Ahn G, Woods EC, Läubli H, Bertozzi CR. Targeted glycan degradation potentiates the anticancer immune response in vivo. Nat Chem Biol 2020;16:1376–1384.Ethics ApprovalColorectal tumor and adjacent normal mucosal tissue were obtained from patients undergoing colon tumor resection at University Hospital Galway under an ethically approved protocol (Clinical Research Ethics Committee, Ref: C.A. 2074). Samples were collected and isolated by the Blood Cancer Network of Ireland under an ethically approved protocol. Written informed explicit consent was obtained from all patients prior to sampling. Mice were housed and maintained following the conditions approved by the Animals Care Research Ethics Committee of the National University of Ireland, Galway (NUIG) and procedures were conducted under individual and project authorisation licenses from the Health Products Regulatory Authority (HPRA) of Ireland or from the Ethical Committee for Animal Experiments, Vrije Universiteit Brussel (license no. LA1230281, 16-281-6).

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Abstract 4762: Deficient double strand breaks repair of bone marrow plasma cells correlates with better clinical outcome of multiple myeloma patients

10.1158/1538-7445.am2014-4762 ◽

2014 ◽

Author(s):

Maria Gkotzamanidou ◽

Masood Shammas ◽

Evangelos Terpos ◽

Sathees C. Raghavan ◽

Kenneth C. Anderson ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Clinical Outcome ◽

Plasma Cells ◽

Double Strand Breaks ◽

Strand Breaks ◽

Bone Marrow Plasma

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T Cells Genetically Modified to Express an Anti–B-Cell Maturation Antigen Chimeric Antigen Receptor Cause Remissions of Poor-Prognosis Relapsed Multiple Myeloma

Journal of Clinical Oncology ◽

10.1200/jco.2018.77.8084 ◽

2018 ◽

Vol 36 (22) ◽

pp. 2267-2280 ◽

Cited By ~ 212

Author(s):

Jennifer N. Brudno ◽

Irina Maric ◽

Steven D. Hartman ◽

Jeremy J. Rose ◽

Michael Wang ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

Partial Response ◽

B Cell ◽

Residual Disease ◽

Cell Maturation ◽

B Cell Maturation ◽

Minimal Residual ◽

B Cell Maturation Antigen

Purpose Therapies with novel mechanisms of action are needed for multiple myeloma (MM). T cells can be genetically modified to express chimeric antigen receptors (CARs), which are artificial proteins that target T cells to antigens. B-cell maturation antigen (BCMA) is expressed by normal and malignant plasma cells but not normal essential cells. We conducted the first-in-humans clinical trial, to our knowledge, of T cells expressing a CAR targeting BCMA (CAR-BCMA). Patients and Methods Sixteen patients received 9 × 106 CAR-BCMA T cells/kg at the highest dose level of the trial; we are reporting results of these 16 patients. The patients had a median of 9.5 prior lines of MM therapy. Sixty-three percent of patients had MM refractory to the last treatment regimen before protocol enrollment. T cells were transduced with a γ-retroviral vector encoding CAR-BCMA. Patients received CAR-BCMA T cells after a conditioning chemotherapy regimen of cyclophosphamide and fludarabine. Results The overall response rate was 81%, with 63% very good partial response or complete response. Median event-free survival was 31 weeks. Responses included eradication of extensive bone marrow myeloma and resolution of soft-tissue plasmacytomas. All 11 patients who obtained an anti-MM response of partial response or better and had MM evaluable for minimal residual disease obtained bone marrow minimal residual disease–negative status. High peak blood CAR+ cell levels were associated with anti-MM responses. Cytokine-release syndrome toxicities were severe in some cases but were reversible. Blood CAR-BCMA T cells were predominantly highly differentiated CD8+ T cells 6 to 9 days after infusion. BCMA antigen loss from MM was observed. Conclusion CAR-BCMA T cells had substantial activity against heavily treated relapsed/refractory MM. Our results should encourage additional development of CAR T-cell therapies for MM.

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CD4+ T-cell killing of multiple myeloma cells is mediated by resident bone marrow macrophages

Blood Advances ◽

10.1182/bloodadvances.2020001434 ◽

2020 ◽

Vol 4 (12) ◽

pp. 2595-2605 ◽

Cited By ~ 1

Author(s):

Ole Audun W. Haabeth ◽

Kjartan Hennig ◽

Marte Fauskanger ◽

Geir Åge Løset ◽

Bjarne Bogen ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Antigen Presenting Cells ◽

Bone Marrow Microenvironment ◽

Cd4 T Cell ◽

Myeloma Cells ◽

Antigen Presenting

Abstract CD4+ T cells may induce potent antitumor immune responses through interaction with antigen-presenting cells within the tumor microenvironment. Using a murine model of multiple myeloma, we demonstrated that adoptive transfer of idiotype-specific CD4+ T cells may elicit curative responses against established multifocal myeloma in bone marrow. This finding indicates that the myeloma bone marrow niche contains antigen-presenting cells that may be rendered tumoricidal. Given the complexity of the bone marrow microenvironment, the mechanistic basis of such immunotherapeutic responses is not known. Through a functional characterization of antitumor CD4+ T-cell responses within the bone marrow microenvironment, we found that killing of myeloma cells is orchestrated by a population of bone marrow–resident CD11b+F4/80+MHC-IIHigh macrophages that have taken up and present secreted myeloma protein. The present results demonstrate the potential of resident macrophages as powerful mediators of tumor killing within the bone marrow and provide a basis for novel therapeutic strategies against multiple myeloma and other malignancies that affect the bone marrow.

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WT1-Peptide Vaccination Shows High Immunogenicity and Clinical Activity in Patients with Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v106.11.406.406 ◽

2005 ◽

Vol 106 (11) ◽

pp. 406-406 ◽

Cited By ~ 3

Author(s):

Keilholz Ulrich ◽

Carmen Scheibenbogen ◽

Anne Letsch ◽

Anne Marie Asemissen ◽

Wolf Karsten Hofmann ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

High Risk ◽

Clinical Outcome ◽

Peripheral Blood ◽

Great Promise ◽

Clinical Activity ◽

Peptide Vaccination ◽

Before And After ◽

Disease Stabilization

Abstract BACKGROUND: The transcription factor Wilms tumor protein 1 (WT1) holds great promise for immunotherapy of leukemia. WT1 is strongly expressed in the majority of leukemic blasts, is essential for blast proliferation, and is spontaneously immunogenic. METHODS: In the present phase II trial, 12 HLA-A2+ patients with AML without curative treatment option, were vaccinated with WT1.126–134 peptide mixed with adjuvant KLH as T-helper protein and GM-CSF 4 times bi-weekly, then monthly. RESULTS: Patients characteristics, immune responses and clinical outcome are shown in table 1. Patient characteristics, immunologic response, and clinical outcome Pat FAB/caryotype previous chemotherapy disease status at study onset no. of vaccinations clinical outcome WT1Tetr+ T cells in PB after vaccination WT1Tetr+ T cells in BM after vaccination *PB, peripheral blood; BM, bone marrow; MDS, myelodysplastic syndrome; MPD, myeloproliferative disease. 1 M4 yes 2.PR 15 CR 12 months 0.49% 0.87% 2 M2 11q23 yes 1.CR 18 cCR 30+ months 0.43% 0.91% 3 M2 no PD 4 SD 3 months 0.42% 0.80% 4 M6 yes PD 4 PD neg. neg. 5 M2 yes 1.PR 6 PD 0.37% 0.51% 6 M1 yes 2. PR 9 PD 0.43% 0.40% 7 M2 yes 2.PR 9 PD 2.00% 1.36% 8 M7 yes PD 4 PD neg. neg. 9 M5b yes 2.CR 12 cCR 8+ months 0.44% 0.33% 10 sAML from MDS no PD 12 SD 8 months 0.23% 0.13% 11 sAML from MPS no PD 12 SD 9+ months 0.22% 0.53% 12 M4 no PD 8 SD 3 months 1.11% 1.35% WT1-specific T cells could be detected in 3 patients before vaccination. An induction or enhancement of a T cell response against WT1 was observed in 10 of 12 patients after 2 – 6 vaccinations ranging from 0.22 to 2.00% (median 0.43%) in peripheral blood and from 0.33 to 1.36% (median 0.80%) in bone marrow as analysed by tetramer and cytokine staining. At study onset 6 patients had progressive AML (PD) with 40 – 90% marrow blasts, 4 patients partial remission (PR) following chemotherapy and two patients complete remission (CR) at high risk for relapse. Four of the 6 patients with progressive AML had disease stabilization for 3, 3, 8 and 9 months, which is ongoing in the latter patient. Disease stabilization was accompanied by a decrease/normalization of peripheral blasts in two patients and a >50% decrease in RBC transfusion requirements in a patient with AML evolved from MDS. One patient with PR at study onset had an early relapse and then achieved CR for 12 months (patient 1). Both patients vaccinated in CR are in continuous hematological CR (cCR) for 8+ and 30+ months (patient 2 and 9). The remaining 5 patients had PD after 4 – 9 vaccinations. Bone marrow WT1 RNA levels as molecular disease marker paralleled the clinical course as they decreased 1 – 2 logs in the 3 patients with CR or cCR after 6 vaccinations (Fig. 1A), stabilized or decreased in all 4 patients with SD (Fig. 1B), and increased 1 – 2 logs in 4 of the 5 patients with PD (Fig. 1B). No significant toxic effects were observed. CONCLUSION: WT1 peptide vaccination can efficiently induce a specific immune response and has clinical activity in the absence of significant toxicity. These results warrant further studies of WT1 vaccination in AML patients at high risk for relapse. Fig. 1 WT1 levels in bone marrow before and after 6 vaccinations in patients with CR or cCR (A), SD (B) or PD (C) after vaccination. Fig. 1. WT1 levels in bone marrow before and after 6 vaccinations in patients with CR or cCR (A), SD (B) or PD (C) after vaccination.

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CD28-Mediated Regulation of Multiple Myeloma Cell Proliferation and Survival.

Blood ◽

10.1182/blood.v106.11.355.355 ◽

2005 ◽

Vol 106 (11) ◽

pp. 355-355

Author(s):

Kelvin P. Lee ◽

Nizar J. Bahlis ◽

Anne M. King ◽

Despina Kolonias ◽

Louise M. Carlson ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Cell Proliferation ◽

T Cells ◽

Cell Survival ◽

Plasma Cells ◽

Survival Function ◽

Myeloma Cell ◽

Serum Starvation ◽

Bone Marrow Biopsies

Abstract Although interactions with bone marrow stromal cells are essential for multiple myeloma (MM) cell survival, the specific molecular and cellular elements involved are largely unknown due to the complexity of the bone marrow microenvironment. The CD28 receptor, which costimulates survival signals in T cells, is also expressed on normal plasma cells and myeloma cells. In MM, CD28 expression correlates significantly with disease progression, also suggesting a pro-survival function. In contrast to T cells however, activation and function of CD28 in myeloma and plasma cells is almost entirely undefined. We found that direct activation of myeloma cell CD28 by anti-CD28 mAb alone induced activation of NFkappaB, suppressed MM cell proliferation and protected against serum starvation and dexamethasone-induced cell death. We hypothesized that the specific CD80/CD86 expressing stromal cell partner of this interaction is a professional antigen presenting cells, in particular dendritic cells. Histological studies demonstrated DC were extensively interdigitated throughout the myeloma infiltrates in patient bone marrow biopsies. In vitro coculture with DC also elicited CD28-mediated effects on MM survival and proliferation, and could be blocked by CD28Ig. Our findings suggest a previously undescribed myeloma:DC cell-cell interaction involving CD28 that may play an important role in myeloma cell survival within the bone marrow stroma. These data also suggest that CD28 may represent a therapeutic target in the treatment of multiple myeloma.

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Spontaneous CD4 and CD8 Memory T Cell Responses Against MUC1 and Carcinoembryonic Antigen in Bone Marrow of Multiple Myeloma Patients.

Blood ◽

10.1182/blood.v110.11.3533.3533 ◽

2007 ◽

Vol 110 (11) ◽

pp. 3533-3533

Author(s):

Mathias Witzens-Harig ◽

Dirk Hose ◽

Michael Hundemer ◽

Simone Juenger ◽

Anthony D. Ho ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

T Cells ◽

T Cell ◽

Carcinoembryonic Antigen ◽

Cd8 T Cells ◽

T Cell Responses ◽

Cd8 T Cell ◽

Cd4 T Cell ◽

Cell Responses

Abstract Introduction: The bone marrow (BM) is a site of induction of tumour antigen specific T cell responses in many malignancies. We have demonstrated in the BM of myeloma patients high frequencies of spontaneously generated CD8 memory T cells with specificity for the myeloma-associated antigen MUC1, which were not detectable in the peripheral blood (PB). Besides MUC1, carcinoembryonic antigen was recently identified as a tumour-associated antigen in a patient with multiple myeloma. Up to now, spontaneous CD4 T cell responses against myeloma-associated antigens have not been reported. We undertook this study to evaluate to what extent spontaneous CD4 T cell responses against myeloma antigens occur during myeloma progression and if MUC1 or carcinoembryonic antigen represent immunogenic targets of spontaneous CD4 and CD8 T cell responses. Methods: Altogether, 78 patients with multiple myeloma were included into the study. Presence of functionally competent antigen specific T cells was evaluated by ex vivo short term (40 h) IFN-γ Elispot analyses. CD4 T cell responses against MUC1 were assessed by stimulation of purified CD4 T cell fractions with antigen pulsed, autologous dendritic cells (DCs) pulsed with two synthetic 100 meric polypeptides (pp1-100ss and (137–157)5 tr) that can be processed and presented via multiple HLA-II alleles. CD4- or CD8 T cell reactivity against carcinoembryonic antigen was assessed on purified CD4- and CD8 T cell fractions by pulsing DCs with highly purified CEA derived from culture supernatants of an epithelial carcinoma cell line. CD8 responses against MUC1 were analyzed by stimulation of HLA-A2+ patients derived purified T cells with DCs loaded with HLA-A2 restricted MUC1-derived nonameric peptide LLLLTVLTV. As negative control antigen for MUC1 polypeptides and CEA human IgG was used for pulsing DCs at identical concentrations while HLA-A2-restricted peptide SLYNTVATL derived from HIV was used as control antigen for LLLLTVLTV. Test antigen specific reactivity was defined by significantly increased numbers of IFN-γ spots in triplicate test wells compared to control wells (p<0.05, students T test). Results: 8 out of 19 tested patients (42%) contained MUC1 specific CD8 T cells in their bone marrow, while MUC1 specific CD4 T cells were detected in the BM of 30% of the cases (3/10). Interestingly, in peripheral blood (PB) CD8 reactivity against MUC1 was detectable in only 1 out of 10 patients while CD4 reactivity in PB was not detectable at all (0/10). CEA was specifically recognized by BM CD8 T cells from 5 out of 30 patients (17%) and by BM CD4 T cells from 5 out of 18 patients (28%). CEA was not recognized by CD4 and CD8 T cells in the PB of the same patients (0/13). Conclusion: Spontaneous T helper responses against tumour-associated antigens occur in the BM at similar levels as antigen specific CD8 T cells responses while they are virtually undetectable in the PB. Compared to CEA, MUC1 induces CD8 T cell responses in a much higher proportion of myeloma patients. Nevertheless, our data suggest that CEA may trigger spontaneous T cell responses against multiple myeloma in a considerable number of patients. Thus, systematic functional analyses of this potential tumour antigen in multiple myeloma appears to be justified.

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