Myeloma bone marrow plasma cells: Evidence for their capacity as antigen-presenting cells

• Published in: Blood 1997-09, Vol.90 (5), p.1960-1967
• Main Authors: YI, Q, DABADGHAO, S, BÖSTERBORG, A, BERGENBRANT, S, HOLM, G
• Format: Article
• Language: English
• Subjects: ADP-ribosyl Cyclase; ADP-ribosyl Cyclase 1; Aged; Aged, 80 and over; Antigen Presentation; Antigens, CD; Antigens, Differentiation - immunology; Biological and medical sciences; Cytokines - biosynthesis; Cytokines - immunology; Female; HLA-DQ Antigens - biosynthesis; HLA-DQ Antigens - immunology; HLA-DR Antigens - biosynthesis; HLA-DR Antigens - immunology; Humans; Immunodeficiencies. Immunoglobulinopathies; Immunoglobulinopathies; Immunopathology; Male; Medical sciences; Membrane Glycoproteins; Middle Aged; Multiple Myeloma - immunology; Multiple Myeloma - pathology; NAD+ Nucleosidase - immunology; Plasma Cells - immunology; Plasma Cells - pathology; Tumor Cells, Cultured
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.v90.5.1960

Myeloma plasma cells constitute 10% to 90% of the total bone marrow cell count in patients with multiple myeloma (MM). These cells express a variety of cell surface markers, such as HLA-ABC and HLA-DR, and surface antigens that are necessary for professional antigen-presenting cells, including adhesion and costimulatory molecules. In this study, we examined the expression of major histocompatability complex (MHC) and costimulatory molecules on CD38(bright,++) plasma cells in bone marrow aspirates from eight MM patients. Small percentages of plasma cells expressed weak but detectable levels of HLA-DR, HLA-DQ, CD40, CD80, and CD86, which could be upregulated by interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha. CD38++ plasma cell and CD38(dim,+) cells were sorted from freshly isolated bone marrow mononuclear cells and tested for their capacity to act as antigen-presenting cells. Indeed, both CD38++ plasma cells and CD38+ cells were able to stimulate allogeneic T cells and present the soluble antigens purified protein derivative and tetanus toxoid to autologous T cells. Recognition of the antigens led to T-cell proliferation and secretion of IFN-gamma and was MHC class-I and -II restricted. Antigen processing and presentation by CD38++ and CD38+ cells were abolished by treatment of the cells with chloroquine. Hence, our study provides for the first time evidence that myeloma plasma cells may act as antigen-presenting cells. Further studies are warranted to examine in detail the molecules required for inducing T-cell stimulation.