A cell line, JHC-2, was established from the peripheral blood of a pat
ient with hairy cell leukemia (HCL)-Japanese variant. The JHC-2 cells
have cytologic features similar to those of the original tumor cells.
They displayed hairy cytoplasmic projections by phase contrast and sca
nning electron microscopy. The tartrate-resistant acid phosphatase rea
ction was weakly positive. The immunophenotype of the JHC-2 cells was
CD5-, CD10-, CD11c+/0, CD19+, CD21+, CD23+, CD24-, CD25+, CD38- and FM
C-7+. The expression of surface immunoglobulin (IgG, re) and the confi
guration of Ig gene rearrangements in the JHC-2 cells were identical t
o those in the original leukemic cells, and the JHC-2 cells displayed
trisomy 9 on cytogenetic examination. Southern blot analysis for the E
pstein-Barr virus (EBV) genome showed that the JHC-2 cells contained t
he EBV genome, although the freshly isolated leukemic cells did not. T
hese results indicate that the JHC-2 cell line is an EBV spontaneously
transformed B cell line originating from HCL cells.