Chromosome abnormalities in B-cell prolymphocytic leukemia: a study of nine cases

A new case of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia: a case study

Background

The B-cell prolymphocytic leukemia (B-PLL) diagnosis is challenging due to the superposition with mature B-cell leukemia and/or lymphoma.

Objective

An insight case study of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia.

Subject and methods

A 72-year-old man was referred to the Hematology Department, Qilu Hospital, Shandong University, because of persistent fever (10 days) and lymphocytosis. A detailed diagnostic methods including complete blood count, bone marrow aspiration, flow cytometry, conventional karyotype analysis, fluorescence in situ hybridization (FISH), quantitative real-time polymerase chain reaction (qRT-PCR), next-generation sequencing technology (NGS) used to detect 41 kinds of mutant genes related to hematological malignancies were conducted and reasonable therapeutic regimens including emergent leukapheresis accompanied by basification of urine and hydrotherapy, followed by a regimen of cyclophosphamide and dexamethasone.

Results

Subject white blood cell count was 143.43 × 109/L, and 56% prolymphocytes. He did not show lymphadenopathy but splenomegaly. Immunophenotyping of prolymphocytes was CD5(+low), CD10(−), CD11c(−), CD19(+), CD20(+), cCD22(+), CD23(−), cCD79a(+), CD79b(+), FMC7(±), CD43(−), CD3(−), CD56(−), CD103(−), HLA-DR(+), and Lambda(+). R-banding and FISH revealed that leukemia cells carried extra chromosome 5. Considering the rare occurrence of trisomy 5 found in prolymphocytic leukemia, especially in Asians, with rapid disease progression. We know that median survival of B-PLL is three years after diagnosis, while survival time of this patient was only 1 month.

Conclusion

This study could provide the firsthand materials for precision, medicine and mechanism research in cytogenetics and molecular biology. It inferred that trisomy 5 might be a poor prognosis indicator, providing directions for clinical practice in the foreseeable future.

Prolymphocytic Leukemia: New Insights in Diagnosis and in Treatment

PURPOSE OF REVIEW

We aimed to produce a comprehensive update on clinical and biological data regarding two rare lymphoid neoplasms, B and T prolymphocytic leukemias, and assess therapeutic management in the light of new molecular insights and the advent of targeted therapies.

RECENT FINDINGS

B cell prolymphocytic leukemia (B-PLL) diagnosis remains challenging in the absence of clear immunophenotypic or cytogenetic signature and overlap with mantle cell lymphoma. New molecular defects have been identified in T cell prolymphocytic leukemia (T-PLL), especially in the JAK STAT pathway. Like in chronic lymphocytic leukemia (CLL), B-PLL treatment depends on the presence of TP53 dysfunction. In T-PLL, alemtuzumab still remains the standard of care. Allogeneic transplantation is the only curable option. Thanks to reduced intensity conditioning regimens, it has become accessible to a larger number of patients. PLL prognosis remains poor with conventional therapies. However, great advances in the understanding of both T- and B-PLL pathogenesis lead to promising new therapeutic agents.

How I treat prolymphocytic leukemia

T- and B-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Recent studies have highlighted the role of specific oncogenes, such as TCL-1, MTCP-1, and ATM in the case of T-cell and TP53 mutations in the case of B-cell prolymphocytic leukemia. Despite the advances in the understanding of the biology of these conditions, the prognosis for these patients remains poor with short survival and no curative therapy. The advent of monoclonal antibodies has improved treatment options. Currently, the best treatment for T-PLL is intravenous alemtuzumab, which has resulted in very high response rates of more than 90% when given as first-line treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival, and the latter may offer potential cure. In B-PLL, rituximab-based combination chemo-immunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should be managed using an alemtuzumab-based therapy. The role of allogeneic transplant with nonmyeloablative conditioning needs to be explored further in both T- and B-cell PLL to broaden the patient eligibility for what may be a curative treatment.

Pathology of chronic lymphocytic leukemia: an update

Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) is a clonal lymphoproliferative disorder characterized by proliferation of morphologically and immunophenotypically mature lymphocytes. CLL/SLL may proceed through different phases: an early phase in which tumor cells are predominantly small in size, with a low proliferation rate and prolonged cell survival, and a transformation phase with the frequent occurrence of extramedullary proliferation and an increase in large, immature cells. Although some patients with CLL have an indolent disease course and die after many years of unrelated causes, others have very rapidly disease progression and die of the disease within a few years of the diagnosis. In the past few years, considerable progress has been made in our ability to diagnose and classify CLL accurately. Through cytogenetics and molecular biology, it has been shown that CLL and variants are associated with a unique genotypic profile and that these genetic lesions often have a direct bearing on the pathogenesis and prognosis of the disease. Similarly, the development of antibodies to new biologic markers has allowed the identification of a unique immunophenotypic profile for CLL and variants. Moreover, accumulating evidence suggests that CLL cells respond to selected microenvironmental signals and that this confers a growth advantage and an extended survival to CLL cells. In this article, we will review the progress in the pathobiology of CLL and give an update on prognostic markers and tools in current pathology practice for risk stratification of CLL.

B-prolymphocytic leukaemia with t(11;14) revisited: a splenomegalic form of mantle cell lymphoma evolving with leukaemia

We reviewed eight cases that were diagnosed before 1995 with B-prolymphocytic leukaemia (B-PLL) harbouring t(11;14)(q13;q32) and/or cyclin D1 staining. Thirteen B-PLL patients without t(11;14) were selected as controls. Peripheral blood, bone marrow and histological sections were re-examined without cytogenetic information. Final diagnosis was made using morphology, cytogenetics, immunophenotype and immunohistochemistry. Clinical characteristics were similar for both groups except for younger age, male predominance and extranodal involvement in cases with t(11;14). CD5 was more frequently positive in the t(11;14)+ group (80%) than in the t(11;14)- group (31%). Surface membrane immunoglobulin was strongly expressed by all t(11;14)+ cases, but only 45% of t(11;14)- cases. Histopathological and cytological review of cases with t(11;14) showed an infiltrate with a mixture of cells, some resembling prolymphocytes and others with mantle cell lymphoma (MCL) morphology. Blood films of cases with t(11;14) showed features suggestive of B-PLL in three, and in others, a mixture of cells resembling MCL and nucleolated ones; none corresponded to the blastoid form of MCL. We suggest that 'B-PLL' with t(11;14) may represent a splenomegalic form of MCL evolving with leukaemia. These cases illustrate the importance of tissue diagnosis with cyclin D1 staining and fluorescence in situ hybridization analysis in B-cell leukaemia with prolymphocytic features.

Mature B-cell leukemias with more than 55% prolymphocytes. A heterogeneous group that includes an unusual variant of mantle cell lymphoma

We studied 20 cases of mature B-cell leukemia with more than 55% prolymphocytes in peripheral blood or bone marrow, fulfilling the French-American-British criteria for B-cell prolymphocytic leukemia (PLL). Cases segregated into 3 groups: de novo PLL, 6; PLL occurring in patients with a previous well-established diagnosis of chronic lymphocytic leukemia (PLL-HxCLL), 10; and t(11;14)(q13;q32)-positive neoplasms, 4. All cases expressed monotypic immunoglobulin light chain, and most were positive for CD5. All t(11;14)-positive neoplasms were CD23- and uniquely positive for cyclin D1. Cytogenetic abnormalities were present in 19; in all 19, the karyotype was complex, indicating clonal evolution and genomic instability. The most frequent cytogenetic abnormality in de novo PLL involved chromosome 7 in 4 cases. Trisomy 12 or add(12p) was present in 4 cases of PLL-HxCLL. We conclude that mature B-cell leukemias with more than 55% prolymphocytes are a heterogeneous group that includes t(11;14)-positive neoplasms, which we suggest are best classified as mantle cell lymphoma. We also suggest that prolymphocytic morphologic features are a common end-stage of transformation for several B-cell neoplasms.

A transcription map of the minimally deleted region from 13q14 in B-cell chronic lymphocytic leukemia as defined by large scale sequencing of the 650 kb critical region

Extensive analysis of tumors has demonstrated homozygous and heterozygous deletions in chromosome region 13q14.3 in B-cell chronic lymphocytic leukemia (B-CLL), suggesting the site of a tumor suppressor gene. Since previous searches for this gene have not yielded any viable candidates, we now present the sequence of the BACs which span the minimally deleted approximately 650 kb region between markers D13S319 and D13S25. This sequence has allowed us to create the definitive transcription map for the region which reveals 93 ESTs and 12 Unigene clusters in this region. Using gene prediction programs, a further 19 potential genes are also identified. The genes show an asymmetrical distribution throughout the region with most of them clustering at the extreme ends. This sequencing effort provides for the definitive structure of the B-CLL deletion region and the identification of the vast majority of the potential candidate genes. Of all the genes identified, only three have homologies to known genes: two L1 repeat genes and rabbit epididymal protein 52. This 13q14.3 sequence provides the final substrate from which to characterize the B-CLL tumor suppressor gene.

Cytogenetic abnormalities in three patients with B-cell prolymphocytic leukemia

We present the cytological features, conventional cytogenetics, and in situ hybridization (ISH) findings of three cases of B-cell prolymphocytic leukemia (B-PLL). The diagnosis was made according to the French-American-British (FAB) criteria. We considered a diagnosis of B-PLL when a predominance (> 50%) of lymphoid cells with coarse chromatin but prominent central nucleoli and more abundant cytoplasm than typical chronic lymphocytic leukemia (CLL) cells were present. B-PLL express strong SIg, B-cell antigens, and reactivity with the monoclonal antibody FMC7. Chromosome analysis was carried out on lymphoid cells from peripheral blood and, in one patient, from lymph node. The phytohemagglutinin (PHA) mitogen was used. ISH was performed with two types of probes: the biotin-labeled chromosome 12-specific alpha satellite DNA probe to detect trisomy 12, and biotin-labeled libraries of whole chromosomes 1, 7, and 14. Clonal chromosome abnormalities were found in all three patients; in one, a complex karyotype was observed. The most frequent recurrent abnormality was trisomy 12. Our results suggest that PLL usually presents with cytogenetic abnormalities. The finding of translocation (11;14) is noteworthy; chromosomes 1 and 3 are also involved.

Cytogenetic studies in seventy-six cases of B-chronic lymphoproliferative disorders

The results of cytogenetic studies are reported in 76 patients with B-chronic lymphoproliferative disorders (B-CLPD): 60 patients with chronic lymphocytic leukemia (CLL), six with follicular lymphoma in leukemic phase (FLLP), five with splenic B-cell lymphoma with villous lymphocytes (SLVL), two with chronic prolymphocytic leukemia (CPL), two with hairy cell leukemia (HCL), and one with plasma cell leukemia (PCL). PHA (phytohemagglutinin), PWM (pokeweed mitogen), LPS (lipopolysaccharide from Escherichia Coli), TPA (phorbol 12-myristate acetate), IL6 (interleukin 6), and DxS (dextran sulfate) were used as mitogens. Mitoses were obtained in 75 cases. Clonal aberrations could be demonstrated in 34 cases (44%). In CLL, classical type, chromosomes 6, 11, and 13 were more frequently involved, whereas trisomy 12 was frequently found in CLL mixed-cell type, in FLLP, and CPL. In SLVL the deletion del(7)(q32) is noteworthy and miscellaneous chromosome abnormalities in the remaining patients were observed. Regarding the efficiency of mitogens, PHA turned to be the most effective in obtaining metaphases and in detecting clonal chromosomal aberrations.

A scoring system for the classification of CD5-B CLL versus CD5+ B CLL and B PLL

B CLL is a monoclonal proliferation of lymphocytes which express the CD5 antigen (CD5+ CLL). Rare exceptions (less than 10%) are CD5-, as are the majority of B PLL. We have studied the clinical, cytological and immunophenotypic characteristics of a series of 12 CD5-CLL and have established a score which allows the distinction between CD5+ CLL, CD5- CLL and PLL. Among the CD5- CLL, there were significantly more cases with advanced stage (Rai and Binet) and splenomegaly. The cytological study found more mixed CLL according to FAB classification (more prolymphocytes). There were significantly more CD23-, FMC7+, SIg strong positive cases. A score from 0 to 6 was established based on clinical, cytological and immunophenotypic criteria. Typical CD5+ CLL was scored 0, score 6 corresponded to typical PLL. There were significantly more higher scores amongst CD5- CLL. It therefore appears that CD5- CLLs share certain features with B PLL. The use of this scoring system will allow determination of prognosis within these different categories, thus identifying groups which require specific therapy.

Chronic lymphoid leukemias: recent advances in biology and therapy

There exists a wide variety of lymphoid leukemias derived from B and T lymphocytes. These diseases have distinct immunologic and biologic features as well as varied responses to therapeutics. The most common lymphoid leukemia is chronic lymphocytic leukemia (CLL) which is a clonal proliferation of a subset of B cells expressing the CD5 antigen. Prolymphocytic leukemia is usually derived from B cells and shares some features with CLL but is clearly a distinct entity. Hairy-cell leukemia is a B cell malignancy that is uniquely responsive to a variety of biologic and chemotherapeutic agents. Waldenström's macroglobulinemia is a B cell malignancy that secretes immunoglobulin M (IgM) and may present with the hyperviscosity syndrome. Other B cell malignancies that less commonly present as leukemias include non-Hodgkin's lymphomas such as follicular lymphoma or mantle zone lymphoma. Multiple myeloma may rarely present or evolve into a plasma cell leukemia, typically in far advanced disease. T cell malignancies that may present as chronic lymphoid leukemias, and in the past have often been referred to as T cell chronic lymphocytic leukemia, are large granular lymphocytic leukemia, adult T cell leukemia/lymphoma, Sézary cell leukemia and rare cases of non-Hodgkin's lymphoma that are T cell derived and may present or evolve into a leukemic phase. There is also a rare T cell counterpart of prolymphocytic leukemia. Distinguishing these diseases is critical for optimal care of these patients.

Cytogenetics in CLL and related disorders

Chromosome analysis of more than 1200 patients with chronic lymphocytic leukaemia reported to the International Working Party on Chromosomes in CLL and in the literature is analysed. Clonal chromosomal abnormalities are found in about half of the patients, and one third of those with clonal aberrations have trisomy 12, with or without additional changes. The most common structural abnormalities involve the long arm of chromosome 13, usually as deletions involving 13q14, the site of the retinoblastoma gene. Other recurrent abnormalities are deletions of the long arms of chromosome 11 and 6. 14q+ markers are frequent in patients at advanced stage, but are almost always within complex abnormalities. The number of clonal abnormalities in the CLL cells has a strong prognostic impact. Trisomy 12 as a single abnormality is an adverse prognostic sign, whereas patients with 13q abnormalities generally do comparatively well. Lymphoid leukaemia with monoclonal immunoglobulin secretion frequently involves clonal chromosomal abnormalities, and the type of change is similar to that seen in true CLL. In B cell prolymphocytic leukaemia, t(11;14) is a common finding, together with trisomy 12. T cell prolymphocytic leukaemia is characterized by an inversion of the long arm of chromosome 14, with breaks at q11 and q32, and trisomy of 8q, whereas large granular lymphocytic leukaemia has shown no consistent abnormality. Hairy cell leukaemia seems to involve a specific set of non-random chromosome abnormalities, such as inv(5)9.

Translocation t(11;14)(q13;q32) in chronic lymphoid disorders

The translocation t(11;14)(q13;q32) has been described in a spectrum of B-lymphoproliferative diseases and involves a putative oncogene, BCL1, which maps to chromosome band 11q13. Recent evidence indicates that this abnormality may delineate particular subtypes of lymphoma, such as intermediate lymphocytic and centrocytic lymphomas. Thus the possible significance of the t(11;14) within B-cell disorders should be reexamined in the light of a more objective approach to classifying these diseases by morphology, histology, and immunophenotype. We describe 16 patients with t(11;14)(q13;q32) from a series of 90 patients with chronic lymphoid disorders in whom clonal chromosome abnormalities were detected. All the cases were leukemic: prolymphocytic (B-PLL; 4/15 cases), chronic lymphocytic leukemia (CLL) with increase in prolymphocytes (2/9 cases), or non-Hodgkin lymphoma in leukemic phase, intermediate (3/4 cases), lymphoplasmacytic (2/2 cases), splenic lymphoma with villous lymphocytes (4/18 cases), and follicular (1 case). None of the CLL (25) or hairy cell leukemia cases (15) had t(11;14). Our findings showed that t(11;14) occurred in leukemias of mature B cells with lymphoplasmacytic features as judged by morphology and immunophenotype.

Trisomy 12 in Epstein-Barr virus-transformed lymphoblastoid cell lines of normal individuals and patients with nonhematologic malignancies

Karyotypes of 36 lymphoblastoid cell lines established by Epstein-Barr virus (EBV) transformation of peripheral blood lymphocytes (PBL) of eight normal individuals and 28 patients with various nonhematologic malignancies were analyzed. In seven lines (19.4%), cells with trisomy 12 were noted, with clonality in two of these lines. In two of 11 metaphases with such trisomy, chromosome 12 was involved in structural rearrangements [t(8;12)(q12;p12) and t(12;12)(q11;q24)]. No cells with trisomy 12 were observed in phytohemagglutinin (PHA)-stimulated PBL cultures of these individuals. In 250 individuals (normal and with nonhematologic malignancies) examined in our laboratory in the last 5 years, extra copies of chromosome 12 in PHA-stimulated PBL cultures were observed in only five of 23,216 cells (0.02%). There were no cases of clonality in these samples. The frequency of an extra chromosome 12 was comparable to that of the other chromosomes except 21 and X, whose frequency of occurrence was 0.08% and 0.09%, respectively. These findings should be considered random events in PHA-stimulated PBL. On the contrary, in lymphoblastoid cell lines established by EBV transformation, trisomy of chromosome 12 was the most frequent numerical abnormality. It was observed in 64.7% of all cases with chromosome gains and therefore could not be considered a random occurrence. The specificity of this phenomenon for EBV transformation is supported by the results of cytogenetic analysis of eight lymphoblastoid cell lines established by an alternative procedure in our laboratory [1]. In 400 cells analyzed not a single cell with trisomy 12 was observed. We suggest that EBV transformation might either randomly induce formation of such cells in immortalized B-cell populations or show potentially blastomogenic cells or proneness to their formation in certain individuals who could be predisposed to develop lymphoproliferative diseases, especially chronic lymphocytic leukemia (CLL) in which trisomy of chromosome 12 is the most common alteration.

Chromosome aberrations in B-cell chronic lymphocytic leukemia. Pathogenetic and clinical implications

Chromosome analyses were performed on leukemic cells from 102 patients with B-CLL, of whom 84 were untreated. B-cell mitogen-induced CLL cells yielded suitable metaphases in 85 patients, and 55 showed clonal chromosomal aberrations. Trisomy 12 was found in 26 patients. In nine patients the + 12 was a single aberration. A 14q + chromosome or deletions of the long arm of chromosomes 6, 11, or 13 were other recurrent aberrations. Patients with Rai stage I or more had more frequently clonal aberrations than patients with stage 0 disease (p less than .02). Patients with clonal aberrations had poorer 5-year survival than those with a normal karyotype (p less than .05). Patients with a high percentage of abnormal metaphases in the sample had poorer prognosis than patients with high admixture of normal metaphases (p less than .01). Of the specific clonal aberrations those with 14q + or trisomy 12 tended to have slightly poorer and those with 6q- or structural aberrations involving the long arm of chromosome 13 tended to have better prognosis than patients with other chromosomal aberrations. A complex karyotype tended to be an adverse prognostic sign. Clonal evolution is rare: complex karyotypes are found at diagnosis and clones with single aberrations did not acquire additional chromosome aberrations despite progressive disease and treatment. Nine hundred and seventy-nine published cases are reviewed, and pathogenetic mechanisms, such as oncogenes and gene dosage, are discussed.

Cytogenetic and molecular studies in patients with chronic myeloid leukemia and variant Philadelphia translocations

Out of 105 Philadelphia (Ph) positive chronic myeloid leukemia patients analyzed, six (5.7%) carried a variant Ph translocation, namely t(6;9;9;10;22)(q24;p13;q34;p15;q11); t(9;13;22)(q34;q21;q11);der(2)(2pter----2q31::9q21---- 9q34::22q11----22qter) and der(9)t(2;9) (9pter----9q21::2q31----2qter);t(7;9;22)(q11;q34 ;q11), 14q + ;t(7;9;22)(q35;q34;q11), and t(9;11;22) (q34;q13;q11), respectively. Five of these patients were analyzed with Southern blotting. Three of them showed an atypical molecular pattern; namely, the patient with t(9;13;22) showed no rearrangement in the breakpoint cluster region (bcr), the patient with t(7;9;22)(q35;q34;q11) showed a 3' deletion, and the patient with t(7;9;22), 14q + showed a bcr rearrangement 3' to the exon 4 of the M-BCR. Chromosome in situ hybridization studies demonstrated that in patient one, a two-step translocation occurred: the first step moved the 3' bcr from chromosome 22 to chromosome 9, and the second moved the terminal part of 22q, carrying the c-sis protooncogene, to 10p. Variant Ph translocations appear to be associated with atypical molecular breakpoints.

Chromosome abnormalities in peripheral T-cell lymphoma

We have studied neoplastic lymph nodes from six patients histologically, immunologically and cytogenetically. Histologically all the cases were classified as peripheral T-cell lymphomas. These were subclassified as T-zone lymphomas in three, large cell 'pale cell' variant in one, large cell immunoblastic in one, and small cell, mycosis fungoides in one. Two had features of angioimmunoblastic lymphadenopathy (AILD). Immunologically all cases expressed CD2 (OKT11) and CD4 (T4). All six cases had clonal chromosome abnormalities, although in four cases the majority of cells were chromosomally normal. Chromosome 3 was most often involved in abnormalities, occurring in five patients. The most common single chromosome abnormality, trisomy 3, was seen in all three cases classified as T-zone lymphoma and in no other cases. In the two cases with features of AILD only numerical abnormalities were seen, whereas in the other cases complicated structural rearrangements were present. Recurring structural abnormalities involved bands 1p12or13, 1q32, 3p25 and 14q11. Our data suggest that cytogenetic analysis may assist in diagnosis and classification of the peripheral T-cell lymphomas.

Recurrent deletions of chromosomes 11q and 3p in anal canal carcinoma

A cytogenetic study of 8 cases of anal canal cancer, including 1 cloacogenic and 7 squamous-cell carcinomas, was performed. All tumors exhibited chromosomal abnormalities. A rearrangement involving the long arm of chromosome 11 was seen in all instances, and, with the exception of the i (11q) found in one tumor, all the observed rearrangements resulted in a deletion of the distal segment. Rearrangements of chromosome 3, detected in 6 tumors, led to a deletion of the short arm in 5 cases. The association of these 2 deletions may characterize the anal canal carcinoma, the smallest common deleted segments being distal to 11q22 or q23 and 3p22.

Clonal chromosome abnormalities in chronic lymphocytic leukemia patients revealed by TPA stimulation of whole blood cultures

Cells from 52 patients with chronic lymphocytic leukemia and two patients with prolymphocytic leukemia were stimulated in whole blood or bone marrow culture with the polyclonal B-cell mitogen tetradecanoyl phorbol acetate (TPA). Stimulation was successful in 50 of the 54 cases. Comparison with Epstein-Barr virus and pokeweed mitogen showed them to be much less successful mitogens under the conditions used. Twenty-one patients (39%) were found to have clonal abnormalities that were probably disease-related. The most common abnormality was trisomy 12 (five patients). Four patients had a deletion of the long arm of chromosome #11 and one patient had a t(11;14). Five patients had abnormalities of the long arm of chromosome #13, with four probably having breaks in band q14. Two patients were seen with trisomy 3 as the only abnormality. Overall, the results were similar to those of other groups, which shows that considerable karyotypic information can be obtained from the use of a single mitogen on a large series of chronic lymphocytic leukemia patients.

Cytogenetic studies in hairy cell leukemia

Cytogenetic analyses were performed on cells from 17 patients with hairy cell leukemia stimulated with polyclonal B-cell activators (in 155 different cultures). No mitosis was obtained in samples from four cases (23.5%). Of 14 bone marrows, four (28.6%) showed mitoses, two with clonal abnormalities. All four samples from the spleen had mitoses with four clonal changes; eight of 13 (37.5%) blood samples had mitoses with three clonal changes. Of the polyclonal B-cell activators (PBA), lipopolysaccharide and protein A seemed to be effective for the detection of clonal abnormalities in hairy cell leukemia. Among the clonal aberrations, chromosomes #3, #10, and #17 were affected in two cases each; frequent numerical changes were monosomies of #10 and #17 and structural changes were deletions at band 3p21 (two cases), 6q-, and der(9)t(9;?)(p22;?). The chromosomal bands involved in structural changes were close to accepted constitutive fragile sites.

Activation of malignant B-lymphocytes: pathophysiologic and clinical importance

Recent advances in clarifying the activation mechanisms of the normal immune system have provided the basis for successful experiments concerning the activation of malignant lymphocytes. Such studies with malignant cells, freshly sampled from patients with lymphoproliferative diseases, can be used for pathophysiological considerations, analysis of tumor evolution, classification of malignant subsets, and karyotyping. Of particular interest is the possibility of abrogating the maturation arrest in some clonally-restricted cells. This might lead to therapeutical implications, since the differentiation blockage plays a fundamental role in the clonal expansion and pathogenesis of tumors. Recently, it has been shown that interferon (IFN) can be a potent inducer of various degrees of transformation, differentiation and even proliferation in different subsets of normal and malignant B cells. This may be important in explaining the divergent results of IFN treatment in various malignant B-cell disorders.

Two new cell lines from B-prolymphocytic leukaemia: characterization by morphology, immunological markers, karyotype and Ig gene rearrangement

Leukaemic cells from 2 patients with B-prolymphocytic leukaemia were immortalized in vitro by means of Epstein-Barr virus and phorbol-ester TPA. The resulting cell lines, named JVM-2 and JVM-3, have been growing continuously in liquid culture for more than one year. JVM-2 is characterized cytogenetically by t(11;14)(q13; q32), and JVM-3 by trisomy 12. The immunoglobulin (Ig) heavy- and light-chain genes showed the same pattern of rearrangement in both lines as in the original prolymphocytes from each case. The cells from these lines showed a spectrum of morphological and immunological features corresponding to different stages of B-cell maturation. The expression of Ig, IgM-lambda in JVM-2 and IgMD-K in JVM-3, changed from a predominantly membrane pattern in the original cells to a cytoplasmic one in the cell lines. By comparison with their original progenitors, the cells from both lines showed reduced reactivity with the monoclonal antibody (MAb) FMC7, and increased expression of the antigens recognized by the MAbs OKT10, alpha-Tac, FMC53 and Ki-I. The availability of cell lines from this rare type of lymphoid leukaemia offers a potential tool for the study of molecular events associated with the expression of Ig and other antigens by neoplastic cells.

Del(3)(p13) in B-prolymphocytic leukemia--a new nonrandom chromosomal aberration possibly related to the c-ras oncogene

Cytogenetic analysis was performed on the leukemic cells from two patients with B-prolymphocytic leukemia. Both patients had del(3)(p13) chromosomal abnormality, as well as other clonal aberrations. Del(3p) was previously reported in one case of B-cell prolymphocytic leukemia, and is known to be a specific aberration in small-cell carcinoma of the lung. In B-cell prolymphocytic leukemia, as in other B-lymphocytic leukemias/lymphomas, the karyotype often involves chromosomes #3, #6, #11, and #12. All of these chromosomes are suggested sites for the c-ras oncogene family.

Neoplastic kappa and lambda cells in a B-PLL with chromosome translocations of both light chain gene regions

We describe a chromosome translocation t(2;13) (p11-12;p11) involving the kappa (kappa) light chain gene region (2p11-12), and a subsequent translocation t(11;22) (q23;11) involving the lambda (lambda) light chain gene region (22q11) within the same clone, in a patient with B-cell prolymphocytic leukaemia (B-PLL), of whose peripheral mononuclear cells 82% expressed (kappa) chains and 8% expressed (lambda) chains. Electron microscope (EM) studies using the immunogold method showed that both kappa- and lambda-producing cells were prolymphocytes. Immunoglobulin (Ig) gene analysis by Southern blotting demonstrated rearrangement of both Ig heavy (H) chain genes and one kappa gene. Although a lambda gene rearrangement corresponding to the minor lambda-positive population was not detected, a small monoclonal (M) band of IgM-lambda was present in the serum. The chromosome translocations and the pattern of light chain expression, particularly the lambda-producing cells, are discussed in the light of the restricted light chain expression observed in Burkitt's lymphomas with variant translocations involving the light chain genes.

Prognostic significance of chromosome abnormalities in chronic lymphocytic leukaemia

Lymphocytes from 33 out of 63 patients with B-cell chronic lymphocytic leukaemia (B-CLL) were successfully stimulated for cytogenetic analysis by means of two B-cell mitogens: pokeweed mitogen and lipopolysaccharide-B, used after pretreatment of the cells with neuraminidase and galactose oxidase. All patients had abnormal clones in 30-100% of the cells analysed. Chromosomes more frequently involved were Nos. 1, 3, 6, 11, 12, 13 and 14. The most common abnormality was a marker 14q+ (breakpoint 14q32) seen in 17 cases; trisomy 12 was observed in seven cases. A clinical scoring system was used to investigate the correlation of chromosome abnormalities with prognosis. The group with 14q+ was often associated with features of progressive disease, namely; prolymphocytoid or Richter transformation, refractoriness to therapy, high WBC and advanced staging. A significant difference in survival was observed between patients with 14q+ and the rest: median survival from diagnosis being 45 months and over 64 months, respectively (P less than 0.05); when survival was calculated from the time of chromosome analysis the values were 8 months and more than 41 months, respectively (P less than 0.01). It is suggested that 14q+ is acquired during the evolution of CLL and that this development may be a key event in the clinical progression of B-CLL. Other abnormalities, including trisomy 12, were not found to be associated with a worse prognosis.

Telomeric association of chromosomes in B-cell lymphoid leukemia

About 20% of leukemic bone marrow cells from each of two patients with B-cell lymphoid leukemias showed apparent translocations which appeared to be the result of telomeric association. In one patient, whole chromosomes were associated telomere to telomere in pairs; in the other patient, telomeres of whole chromosomes were associated with breakpoints located close to the proximal or distal ends of the heterochromatic band 1q12. Repeated base sequences, particularly (CA)n sequences, are believed to be the basis of telomere pairing, and likewise repeated base sequences of heterochromatin may explain the association of 1qh and telomeres. Telomeric association may be considered as a potential origin of new stable cytogenetic combinations that have a role in oncogene transposition and tumor etiology.

Adult T-cell lymphoma/leukemia in a Caribbean patient: cytogenetic, immunologic, and ultrastructural findings

Cytogenetic findings on immunologically and morphologically characterized leukemic cells from a Caribbean patient with adult T-cell lymphoma/leukemia (ATLL) (HTLV+) are reported. Marker studies on peripheral blood lymphoid cells showed a mature postthymic phenotype: TdT-, OKT3+, OKT4+, OKT6-, OKT8-, 3A1-, anti-HLA-DR-. Light and electron microscopic analysis revealed a great cellular pleomorphism with respect to nuclear features. Three main types of leukemic cell were observed: typical multilobed ATLL lymphocytes, Sézary's syndrome (SS) cells, and cells intermediate between those two. Chromosome studies on PHA-stimulated cultures revealed three clones. The predominant clone was hyperdiploid; significant abnormalities were 1q+, 14q+, and 6q- (breakpoint q21), which are known to occur in lymphoid malignancies, together with trisomy 7q and i(17q), which have been reported previously in Japanese ATLL and the small variant of SS, respectively. The 14q+ marker was t(11;14)(q13;q22-24). The incidence of 6q-, trisomy 7q, and i(17q) varied within the main clone, and it is speculated that these chromosome abnormalities might be related to the variation observed in the cell types of this patient. Two minor clones had 6q- (breakpoint q25) and 13q+ markers, respectively. It was not possible to unequivocally establish the relationship between these three clones. The chromosomal, morphologic, and immunologic findings in this case support a close relationship between ATLL in Japan and in the Caribbean basin, as well as between the proliferating cells of ATLL and SS.