Novel type of proliferating lymphoplasmacytoid cell with a characteristic spotted immunofluorescence pattern.

Abstract

We examined bone marrow from myeloma patients for the presence of cells with the characteristics of the clonogenic cell in the myeloma stem cell assay. We identified a novel type of cell that contained cytoplasmic immunoglobulin of the relevant idiotype located in a cytoplasmic spot. This "spotted" Ig could be located in the rough endoplasmic reticulum. Spotted cells are highly proliferative, as evidenced by the nuclear staining with the antibody Ki67, and were found in the bone marrow from most of the myeloma patients studied. This type of cell was also present in patients with immunocytomas, in some cases of benign monoclonal gammopathy, and in patients in the state of polyclonal hypergmmaglobulinemia. IgG

Immunophenotypic Analysis of Lymphocytes and Myeloma Cells in Patients with Multiple Myeloma

“…In other studies, Lokhorst et al [30] identified a CALLAnegative precursor of myeloma cells which was char acterized by a small cytoplasmic spot of immunoglob ulin of the relevant idiotype. This cell was positive for HB4 and HB6, but did not express other B cell anti gens or plasmacytoid antigens.…”

Autologous bone marrow transplantation therapy for multiple myeloma

“…Moreover, recent reports document the presence of pre-B and B-cell antigens, and even of non-B cell (i.e. myelomonocytic) antigens on myeloma cells, suggesting that an early marrow progenitor cell may be part of the myeloma clone (37)(38)(39)(40)(41)(42)(43). Nonetheless, the phenotype of the "clonogenic" cell remains undefined.…”

“…Several antigens have been described to date on the surface of normal and neoplastic plasma cells and are candidates for use in depleting these cells from autologous marrow prior to BMT for myeloma (29,(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47). We have utilized anti-PCA-1, a MoAb directed to a 26-kilodalton protein on the surface of myeloma cells which is of the IgG2a isotype and therefore capable of complementmediated lysis of antigen-bearing tumor cells in vitro.…”

Long‐term bone marrow cultured stromal cells regulate myeloma tumour growth in vitro: studies with primary tumour cells and LTBMC‐dependent cell lines

“…Both cell lines were plasma cell lines as examined in cytocentrifuge preparations stained with May‐Grünwald‐Giemsa, FACS analysis and immunofluorescence microscopy. Protocols for analysis of surface and cytoplasmic antigen expression by flow cytometry (FACScan (Becton Dickinson, Erembodegem‐Aalst, Belgium)) or immunofluorescence microscopy on cytospin preparations have been described previously ( Lokhorst et al , 1987 , 1994; Bloem et al , 1988 ; Ahsmann et al , 1992 ). Fluorescent stained preparations were viewed with a Leitz Orthoplan phase‐contrast immunofluorescence microscope equipped with K2 and N2 filter systems for FITC and TRITC examination, respectively, and with 4 × eyepieces and 63 × and 95 × objectives.…”