title: Prolymphocytic leukemia of B cell type: rearranged immunoglobulin (Ig) genes with defective Ig production.
abstract: 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.
authors.forename: J V
authors.initials: JV
authors.lastname: Melo
authors.forename: L
authors.initials: L
authors.lastname: Foroni
authors.forename: V
authors.initials: V
authors.lastname: Brito Babapulle
authors.forename: D S
authors.initials: DS
authors.lastname: Lewis
authors.forename: M
authors.initials: M
authors.lastname: Bennett
authors.forename: D
authors.initials: D
authors.lastname: Robinson
authors.forename: L
authors.initials: L
authors.lastname: Parreira
authors.forename: L
authors.initials: L
authors.lastname: Luzzatto
authors.forename: D
authors.initials: D
authors.lastname: Catovsky
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000276:immunology; D002874:Chromosome Mapping; D004247:DNA / Q000032:analysis; D004262:DNA Restriction Enzymes; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000235:genetics; D007136:Immunoglobulins / Q000032:analysis / Q000235:genetics*; D007945:Leukemia, Lymphoid / Q000235:genetics*; D009000:Monocytes / Q000276:immunology / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007136:Immunoglobulins; D004247:DNA; D004262:DNA Restriction Enzymes