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Cellosaurus publication CLPUB00079

Publication number CLPUB00079
Authors Hyjek E., Rafii S., Flore O., Bergsagel P.L., Michaeli J., Knowles D.M., Cesarman E.
Title KSHV/HHV-8 in myelomatous effusions: development of a cell line useful for serologic analysis and viral propagation.
Citation Blood 92 Suppl. 1:96a-96a(1998)
Abstract The Kaposis sarcoma-associated herpesvirus (KSIIV), or human herpesvirus 8 (HHV-8) is consistently present in primary effusion lymphomas (PEL), a rare distinctive type of B cell non-Hodgkin's lymphoma usually originating in the body cavities as an effusion. Involvement of an effusion by malignant myeloma plasma cells is also distinctly rare, occurring in less than 1% of cases of multiple myeloma (MM). We have identified two HIV- negative patients with MM who in addition had a myelomatous effusion. Both myelomatous effusions contained KSHV genome, as evaluated by Southern and Northern blot analyses. KSHV was visualized within all the malignant plasma cells by indirect immunofluorescence assays (IFA). A tumor sample from one of these patients, obtained 4 months before the development of the pleural effusion, had no detectable KSHV by Southern blot analysis, suggesting that KSHV infection of the myeloma cells in the pleural fluid was a secondary event related to tumor progression. EBV was not detected in either case. We have established a cell line from one of these cases. called ME-1. We also screened 21 existing MM cell lines for the presence of KSHV, and failed to identify any other KSHV-positive line. ME-1 cells retain a high episomal copy number of KSHV, and preserve all characteristics of malignant plasma cells, including morphology, cytoplasmic immunoglobulin and expression of plasma cell-associated antigens. KSHV can be induced to replicate in ME-1 cells by treatment with TPA, and infectious particles can be purified. KSHV has been previously reported to be present in bone marrow stromal cells of patients with MM. However, patients with MM do not have serologic reactivity to this virus as determined employing immunofluorescence assays (IFA) using PEL cell lines as substrates, or ELISA using virus purified from such cell lines. We hypothesized that this lack of recognition could be due to the presence of a different viral strain of KSHV in MM patients, that does not cross- react serologically with that of PEL. We tested whether ME-1 contained this putative "MM virus", and therefore contained viral antigens recognized by sera from other patients with MM. We examined serum obtained from 59 patients with MM or MGUS for the presence of antibodies to KSHV. IFA using ME-1 cells showed positivity in only two samples from the same patient, who had homosexuality as a risk factor for KSHV infection. Sera from five patients with KS and one patient with PEL recognized both latent and lytic antigens in ME-1 cells. Therefore, we could not demonstrate the presence of a different, MM-associated virus in this cell line. These results represent the first demonstration of KSHV within malignant myeloma plasma cells, and the development of the first KSHV- positive myeloma cell line. The presence of KSHV in myclomatous effusions but not in plasma cells in other forms of multiple myeloma is highly reminiscent of the presence of KSHV in PEL but not in other types of non- Hodgkin's lymphoma, and further suggests an association behmen KSHV and the effusion phenotype.
Cell lines CVCL_M535; ME-1 [Human myeloma]