| Abstract |
A biphenotypic myeloma cell line (Sa5) has been established from the bone
marrow of a patient with Bence Jones kappa plasma cell leukemia. Sa5
expressed myeloid markers including chloroacetate (specific) esterase and
CD33 (MY9) as well as plasma cell marker PCA-1. Morphologically, Sa5
showed extensive nuclear lobulation, and ultrastructural studies revealed
abundant perinuclear cytoplasmic fibrils. Southern blot analysis showed JK
gene rearrangement. Exogenous IL-6 enhanced proliferation of Sa5. Free
kappa chains could be detected in the supernatant of the culture medium.
Karyotype: 43, X, -X, -8, -13, -14, -16, -17, -18, -18, -20, -21, 1p-, +3p-,
6q-, 8p+, 9q+, 10q+, 22q+, +7mar. Markers of Sa5: PCA-1 97.9%, CD3 0.2%,
CD19 0.7%, CD20 2.9%, CD10 0%, CD13 0.1%, CD33 66.9%, HLA-DR 83.7%,
surface kappa 3.4%, s-lambda 0.9%, cytoplasmic kappa (++), c-lambda (-).
Peroxidase (-), naphthol AS-D chloroacetate (specific) esterase (+), alpha-
naphthyl buthylate (nonspecific) esterase (-), acid phosphatase (+++).
Case: A 62-year-old female. WBC 72.7x10(9)/L (95% plasma cell), Hb 5.3g/dl,
P1 S0x10(9)/L. Bone marrow: NCC 150x10(9)/L. 99.2% plasma cell. LDH 1,396U/L,
Ca 12.6mg/dl, HTLY-1 (-). Cell culture: Bone marrow plasma cells
have been cultured in RPMI 1640 with 10% fetal calf serum since December
1986. Recent studies proved the existence of hybrid or polyphenotypic
myeloma coexpressing myeloid, monocytic and plasma cell antigens (M.
Thomas et al, Blood, 1989). Among these, only myelomonocytic myeloma cell
line (LB-84-1) has already been established (B.G.M. Durie et al, Blood
1989). Sa5, unlike LB84-1, lacking the monocytic marker, myeloid myeloma
cell line Sa5 should provide the alternative model of polyphenotypic
myeloma.
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