Prolymphocytic leukemia of B cell type: rearranged immunoglobulin (Ig)
genes with defective Ig production
JV Melo, L Foroni, V Brito Babapulle, DS Lewis, M Bennett, D Robinson, L Parreira, L Luzzatto and D Catovsky
An unusual case of prolymphocytic leukemia of the B cell type (B-PLL) in a
79-year-old patient is reported. The clinical and cytomorphological
features of the disease were typical of B-PLL, but membrane and cytoplasmic
immunoglobulins (Ig) could not be demonstrated by immunofluorescence
techniques; 3% to 4% of the cells were shown to have IgG kappa in the
cytoplasm by a more sensitive immunoperoxidase method. The cells were
unreactive with a panel of monoclonal antibodies against T cell antigens
but they were positive with B cell lineage reagents: FMC4, anti-HLA-Dr
determinants; FMC7, which reacts with most B-PLL; anti-B1 and anti-B4,
which react with most B cell leukemias. Analysis of Ig genes at the DNA
level demonstrated that both heavy- chain alleles and one kappa chain
allele were rearranged, confirming that the patient's cells were of B
lineage. Chromosome analysis revealed a consistent abnormality,
t(17;21)(p11;p11), in all cells and, in addition, a 14q+ marker in 10% of
the cells. This study highlights the value of DNA analysis techniques for
the characterization of neoplastic B cells. The low rate of expression of
Ig genes, despite their rearrangement, suggests that a specific
transcriptional or posttranscriptional defect must exist in these cells.
Volume 66,
Issue 2,
pp. 391-398,
08/01/1985
Copyright © 1985 by The American Society of Hematology
