Acute myeloid leukaemia M0: haematological, immunophenotypic and cytogenetic characteristics and their prognostic significance: an analysis in 241 patients

Haematological, immunophenotypic and cytogenetic characteristics were analysed in 241 patients with acute myeloid leukaemia (AML) M0, including 58 children. Children < 3 years and adults between 60 and 70 years of age were most frequently affected. Immunophenotyping showed a heterogeneous phenotype. Anti-myeloperoxidase was positive in about half of the patients. Cytogenetic data were available from 129 (54%) patients. A normal karyotype was found in only 24%. Most of the abnormalities were unbalanced and the chromosomes 5, 7, 8 and 11 were the most frequently affected. Survival data were available from 152 treated patients (63%). The median overall survival for all patients was 10 months, 20 months for children (n = 36), 10 months for the young adult group (n = 50) and 7 months for the elderly patients (n = 66) (P = 0.09). Karyotype was not a prognostic factor influencing survival. AML M0 shows the immunological characteristics of early progenitor cells, but the expression of the different markers and cytogenetic abnormalities is heterogeneous. The prognosis is poor compared with other de novo AML and similar to that of AML with multilineage dysplasia or AML following myelodysplastic syndromes.

Interferon alpha and zidovudine therapy in adult T-cell leukaemia lymphoma: response and outcome in 15 patients

Adult T-cell leukaemia lymphoma (ATLL) is an aggressive disease caused by the human T-lymphotropic virus 1 (HTLV-I) with a short survival. Responses to interferon alpha (IFN-alpha) and zidovudine (AZT) have been documented but not with long-term follow-up. We treated 15 ATLL patients with IFN and AZT. Eleven patients had acute ATLL, two had lymphoma and two smouldering ATLL, with progression. The main features were: organomegaly (14), skin lesions (10), high white blood cell (WBC) count (11) and hypercalcaemia (9). Eleven patients had previously received chemotherapy and one had received an autograft. At the time of the study, seven patients had progressive disease and eight were in partial or complete clinical remission. Responses (PR) lasting 2+ to 44+ months were seen in 67%; 26% did not respond (NR) and one patient was not evaluable. Hypercalcaemia predicted a poor outcome but differences were not significant. Eight of the 15 patients have died 3-41 months from diagnosis. Median survival for the 15 patients was 18 months. Survival of the NR ranged from 4 to 20 months; six PR patients are alive 8-82 months from diagnosis. The differences in survival between NR (median: 6 months) and PR (55% of patients alive at 4 years) were statistically significant (P = 0.002). In conclusion, IFN and AZT improves the outcome of ATLL patients and helps maintain responses.

t(2;5) associated with a histiocytic-monocytic neoplasm

We describe a patient with a neoplasm derived from the histiocytic-monocytic lineage associated with t(2;5) detected by FISH. The patient presented with bone marrow involvement, no organomegaly and subsequently developed a leukaemic picture. The clinical course was aggressive and the patient died four months from diagnosis. Cell morphology, immunophenotype (CD30-, EMA-, Lisozyme+, cy CD68+ and CD45+) and DNA analysis showing germ-line configuration of the Ig/TCR chain genes ruled out the diagnosis of anaplastic large cell lymphoma (ALCL). This unusual case ilustrates that t(2;5) is not exclusive for ALCL but may be found in a few cases of rare neoplasms derived from the histiocytic-monocytic cells.

Cyclin D1 by flow cytometry as a useful tool in the diagnosis of B-cell malignancies

The translocation (11;14)(q13;q32) and its molecular counterpart the BCL-1 rearrangement are features observed in mantle cell lymphoma (MCL) and less commonly in other B-cell disorders. This rearrangement leads to cyclin D1 overexpression, which may be the main pathogenic event in these tumours and is therefore recognised as a diagnostic marker. We developed a flow cytometry method to detect cyclin D1 overexpression using the monoclonal antibody (MoAb) 5D4, and characterised its frequency in 93 B-cell malignancies. The competitive reverse transcriptase polymerase chain reaction (RT-PCR) for cyclin D1, D2 and D3 was then performed on 40 of these cases to assess the validity of the flow cytometry method. Fluorescence in situ hybridisation (FISH) to detect t(11;14)(q13;q32) was carried out on 31 cases and results were compared with cyclin D1 expression by flow cytometry. Twenty five cases showed cyclin D1 expression using 5D4, including MCL (12/13, 92%), chronic lymphocytic leukaemia (CLL) (4/30), B-prolymphocytic leukaemia (B-PLL) (1/4), splenic lymphoma with villous lymphocytes (SLVL) (4/13), hairy cell leukaemia (HCL) (1/7) and other B-non Hodgkins Lymphoma (B-NHL) (3/15). There was a good correlation between flow cytometry results and RT-PCR in 36/40 cases (90%), and with FISH for t(11;14) in 25/31 cases (80%). We concluded that the detection of cyclin D1 expression by flow cytometry in cell suspensions could be applied routinely to the study of B-lymphoproliferative disorders and may be of value for their diagnosis and management.

Disease features in acute myeloid leukemia with t(8;21)(q22;q22). Influence of age, secondary karyotype abnormalities, CD19 status, and extramedullary leukemia on survival

Over a period of 14 years, 50 patients (12 children and 38 adults) of whom 46 had acute myeloid leukemia (AML) and 4 had myelodysplastic syndrome characterized by the t(8;21)(q22;q22) translocation were referred to the Royal Marsden Hospital. The clinicopathological features of these cases were analyzed to determine the influence of age, secondary karyotype abnormalities, and expression of the lymphoid marker CD19 on event free survival, and presence of extramedullary leukemia on overall survival. They were treated with a variety of chemotherapy protocols and some had bone marrow transplantation. There appeared to be no difference in survival between children (age <17 years) and adults (age >16 years). Out of the 50 cases, 16 (32%) had the (8;21) translocation alone, 17 (34%) had additional loss of a sex chromosome and the remaining 17 (34%) had other karyotype abnormalities of which deletion or translocation of the long arms of a #9 was most common (observed in 8 of the 17 patients). The karyotype groups had a significant impact on survival, the group with loss of a sex chromosome having a poorer outcome and the group with abnormalities of chromosome 9 having a better outcome. CD19 positivity was seen in 21 of the 33 cases (63%) in whom it was measured compared to 11% observed in controls with AML without a t(8;21). CD19 status did not exert any influence on event free survival. Extramedullary leukemia (EML) occurred in 5 of the 50 cases (10%). In one patient it was observed at diagnosis but in the others it presented concurrent with bone marrow relapse. The overall survival of patients with EML was worse than that of the other patients but did not achieve statistical significance and was probably adversely affected by other factors.

Linkage analysis for major histocompatibility complex-related genetic susceptibility in familial chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) shows evidence of familial aggregation, but the genetic basis is poorly understood. The existence of a linkage between HLA and Hodgkin lymphoma, another B-cell disorder, coupled with the fact that CLL is frequently associated with autoimmune disease, led to the question of whether the major histocompatibility complex (MHC) region is involved in familial cases of CLL. To examine this proposition, 5 microsatellite markers on chromosome 6p21.3 were typed in 28 families with CLL, 4 families with CLL in association with other lymphoproliferative disorders, and 1 family with splenic lymphoma with villous lymphocytes. There was no evidence of linkage in these families to chromosome 6p21.3. The best estimates of the proportions of sibling pairs with CLL that share 0, 1, or 2 MHC haplotypes were not significantly different from the null expectation. This implies that genes within the MHC region are unlikely to be the major determinants of familial CLL. (Blood. 2000;96:3982-3984)

Quantitative expression of CD23 and its ligand CD21 in chronic lymphocytic leukemia

BACKGROUND AND OBJECTIVES

Cells from the great majority of patients with chronic lymphocytic leukemia (CLL) express CD23. A recent histologic study has shown that CD23 is expressed more strongly in the proliferating centers of the lymph nodes, where the large prolymphocytoid cells are located. The aim of our study was to quantify the expression of CD23 and CD21 in small and prolymphocytoid cells from patients with CLL and B-cell lymphomas, and correlate this expression with clinical parameters.

DESIGN AND METHODS

Using quantitative flow cyto-metry we analyzed the antigen density of CD23 and CD21 in: 1) 101 cases of chronic lymphocytic leukemia, 84 typical, 14 with increased prolymphocytes (CLL/PL) and 3 atypical, 2) 15 cases of CD23 positive B-cell lymphoma with circulating lymphoma cells and 3) 8 normal subjects. The results were correlated with morphology and clinical staging.

RESULTS

Cells from CLL and CLL/PL have a significantly higher number of CD23 molecules than normal and lymphoma B-cells (p<0.001 and p<0.001, respectively). Differences were not significant for CD21. CLL and CLL/PL cases had similar values of CD23 and CD21 molecules, but analysis at a single level showed that prolymphocytes in typical CLL and CLL/PL expressed significantly higher CD23 (p=0.001, p=0.006) and CD21 (p=0.001, p=0.001) than small lymphocytes. There was no correlation between CD23 or CD21 antigen density and clinical stages although there was a trend for a brighter CD23 in stage C patients.

INTERPRETATION AND CONCLUSIONS

Since interaction between CD23 and CD21 is important for B-cell activation, proliferation and tumor formation, findings that both molecules are upregulated in prolymphocytes suggest that this is the proliferating cell component in CLL and underline the association between progression and increased prolymphocytes in typical CLL and CLL/PL.

T-cell prolymphocytic leukaemia: antigen receptor gene rearrangement and a novel mode of MTCP1 B1 activation

T-cell prolymphocytic leukaemia (T-PLL) is a sporadic, mature T-cell disorder in which there is usually an aberrant T-cell receptor alpha (TCRA) rearrangement that activates the TCL1 or MTCP1-B1 oncogenes. As mutations of the Ataxia Telangiectasia (A-T) gene, ATM, are frequent in T-PLL and as ATM seems to act as a tumour suppressor through a mechanism involving V(D)J recombination, we examined V(D)J recombination in T-PLL. Using Southern blotting and the polymerase chain reaction, two of 60 TCRG coding joints were abnormal. In all cases, both TCRD alleles were deleted, IGH was germline, and patterns of TCRB and TCRA rearrangement were normal. However, in a case harbouring t(X;7)(q28;q35), we identified TCRB segment J beta 2.7 juxtaposed to MTCP1 exon 1. This is the first time that TCRB has been implicated in MTCP1 B1 activation. The structure of the breakpoint supports a model in which translocation activates a cryptic MTCP1 promoter. This analysis of V(D)J recombination is consistent with it being a variable that is independent of ATM in T-PLL.

An unusual form of persistent polyclonal B lymphocytosis in an infant

We report a case of persistent polyclonal lymphocytosis in an infant. The circulating lymphocytes were of a small to medium size and a small proportion were larger and had lymphoplasmacytoid features. The presence of either an infectious or mutagenic agent was excluded. The polyclonal B-cell nature of the lymphocyte was demonstrated by immunological markers and confirmed by Southern blot analysis and by polymerase chain reaction targeting immunoglobulin genes. In contrast to the common form of polyclonal lymphocytosis, this case was not associated with HLA-DR7 and/or abnormalities of chromosome 3, p53 or Bcl2/IgH. Whether this lymphocytosis represents a premalignant or a benign condition remains uncertain, although there has been no progression to date.

p53 allele deletion and protein accumulation occurs in the absence of p53 gene mutation in T-prolymphocytic leukaemia and Sezary syndrome

In a series of 24 patients with chronic T-lymphoid disorders [13 T-prolymphocytic leukaemia (T-PLL) and 11 Sezary syndrome] we have studied (i) chromosome 17p abnormalities and p53 allele deletion by fluorescence in situ hybridization; (ii) mutation in the exons of the p53 gene by direct DNA sequencing; and (iii) p53 protein expression by immunocytochemistry and, in some cases, also by flow cytometry with DO-1, a monoclonal antibody to the p53 protein. The study revealed p53 deletion and accumulation of p53 protein in the absence of mutation in the exons that included the hot-spots and differs from that described in B-prolymphocytic leukaemia. Seven T-PLL and five Sezary syndrome patients had p53 overexpression, and five T-PLL and nine Sezary syndrome patients showed p53 deletion. Although the majority of cases with p53 accumulation had p53 deletion, the proportion of cells with the deletion did not correlate with the proportion of cells positive for p53 expression. Two cases of T-PLL showed strong p53 expression in the absence of p53 deletion, and one case of Sezary syndrome with p53 deletion in 97% of cells did not express p53. These findings suggest that a non-mutational mechanism exists for the accumulation of p53 protein in these T-cell disorders. The oncogenic effect of the accumulating wild-type protein has been reported in other malignancies. Whether haploidy resulting from p53 deletion contributes to this mechanism has yet to be determined. Alternatively, the frequent loss of the p53 gene could be associated with the deletion of an adjacent gene, which could be involved in the pathogenesis of these diseases.

Familial chronic lymphocytic leukaemia: a survey and review of published studies

B-cell chronic lymphocytic leukaemia (CLL) is the most common form of leukaemia. To gain insight into the role of inherited factors in the disease, we have conducted a survey of the family histories of 268 CLL patients and have reviewed published familial cases and epidemiological studies. The results of our survey and published studies strongly support the hypothesis that a subset of the disease can be ascribed to a genetic predisposition. The most likely genetic model for inherited predisposition appears to be dominantly acting genes with pleiotropic effects because in many families CLL appears to be associated with other lymphoproliferative disorders.

Pentostatin treatment of cutaneous T-cell lymphoma

Mycosis fungoides is an indolent primary cutaneous T-cell lymphoma (CTCL) that usually progresses from localized skin lesions to systemic disease. Sézary syndrome is a distinct variant characterized by generalized erythroderma and circulating cerebriform cells in the peripheral blood. The malignant cell in both diseases is a mature T cell, usually with a CD4-positive, CD8-negative phenotype. Among the treatment modalities used in these diseases are skin-directed therapy, single-agent and combination systemic chemotherapy, and, more recently, bioimmunotherapy. Pentostatin (Nipent), a potent inhibitor of adenosine deaminase, has activity in a wide range of lymphoid malignancies. At The Royal Marsden Hospital, we treated 29 cutaneous T-cell lymphoma patients with pentostatin, including 16 with Sézary syndrome, 5 with mycosis fungoides, and 8 with other cutaneous T-cell lymphomas. The median age of patients was 61 years (range, 26 to 87 years), with a male-female ratio of 2.5:1. The majority (N = 20) had received prior therapy. Pentostatin was administered at a dose of 4 mg/m2/wk for 4 weeks, and injections were continued every 1 to 2 weeks until maximum response. The overall response rate was 35%. However, only patients with Sézary syndrome achieved a good response, demonstrating an overall response rate of 62% (three complete responses plus seven partial responses). The median disease-free interval for responders was 9 months (range, 3 to 84 months). There was no significant treatment-related toxicity. We conclude that pentostatin is an effective single-agent therapy for patients with Sézary syndrome but not for those with other cutaneous T-cell lymphomas.

Atypical lymphocytes in B-cell chronic lymphocytic leukemia and trisomy 12 studied by conventional staining combined with fluorescence in situ hybridization

Trisomy 12 is one of the most frequent chromosomal abnormalities in B-cell chronic lymphocytic leukemia (CLL), and is predominantly found in CLL with atypical morphology (aCLL). It has been suggested that the atypical morphology might be a feature of the abnormal trisomy 12 clone, but so far it has been difficult to allocate chromosomal aberrations to individual leukemic cells identified by cytomorphology. We therefore wanted to use our MGG/FISH method, which combines fluorescence in situ hybridization (FISH) and standard cytomorphology, to study if the trisomy 12 clone in CLL was restricted to lymphocytes with atypical morphology. Peripheral blood specimens of four patients with aCLL were studied using a DNA probe against the pericentromeric region of chromosome 12. Trisomy 12 was found in 10-34 % of the lymphocytes. In three patients, the proportion of atypical and typical lymphocytes with trisomy 12 was quite comparable, and so was the percentage of atypical cells with lymphoplasmacytoid morphology and those with cleaved nucleus showing trisomy 12. Only one patient differed, since we found an overrepresentation of trisomy 12 among the atypical lymphocytes. However, this could be fully explained by the diluting effect of contaminating T-cells after chemotherapy. The results of the present study show that despite the strong association of trisomy 12 and atypical morphology in CLL, this chromosomal abnormality is not confined to lymphocytes with atypical morphology, but is also found in typical CLL cells. This supports that both cell types have the same clonal origin and that different cell morphology cannot be explained alone by the acquisition of an additional chromosome 12.

Chimeric matrix proteins encoded by defective proviruses with large internal deletions in human T-cell leukemia virus type 1-infected humans

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other diseases. The mechanisms of virus pathogenesis are still obscure. The occurrence of defective proviruses in HTLV-1-infected cell lines and the peripheral blood mononuclear cells (PBMC) of infected individuals is a frequent feature of virus infection. We detected defective proviruses with large internal deletions in PBMC from ATLL and HAM/TSP patients and in asymptomatic HTLV-1 carriers. Seventeen PCR-amplified defective proviruses were sequenced, and three types of deletions were found. Besides truncated MA and the 5' end of the genome, truncated CA, truncated SU, and more frequently truncated TM linked to the pX region were detected. Reverse transcription-PCR analysis of PBMC from ATLL patients and asymptomatic carriers also revealed RNA transcripts with large internal deletions. Analysis of two RT-PCR cDNA clones confirmed a Gag-TM-pX structure of the transcripts. Most defective proviruses contained numerous internal stop codons, but some were capable of coding for the truncated MA linked to a variable out-of-frame peptide. Cloned defective proviruses with long open reading frames were subjected to in vitro transcription-translation followed by radioimmunoprecipitation, which showed expression of chimeric proteins between 8 and 12 kDa. Possible roles of defective proviruses and chimeric proteins are discussed, although there is no firm association with pathogenesis.

Clinical overview of pentostatin (Nipent) use in lymphoid malignancies

We summarize the results of our experience over the past 15 years using pentostatin (Nipent; SuperGen, San Ramon, CA) to treat a range of mature B- and T-cell malignancies. This includes 145 patients with postthymic T-cell malignancies in whom disease subtype was found to be the most significant predictor of response, with the best response rates seen in Sézary syndrome (62%) and T-prolymphocytic leukemia (45%). However, there are no long-term survivors among patients with this group of disorders, and strategies using pentostatin in combination with other therapies, such as CAMPATH-1H, are currently being explored. Among the mature B-cell diseases, pentostatin in both standard- and low-dose regimens is effective in advanced, relapsed/refractory B-chronic lymphocytic leukaemia, showing no cross-resistance with other purine analogs such as fludarabine. Our largest series treated with pentostatin consists of 165 patients with hairy cell leukemia. The follow-up period in this group extends to more than 10 years, with a projected event-free survival rate at 5 years of 60% and an overall survival rate of 97%.

Frequent deletions at 11q23 and 13q14 in B cell prolymphocytic leukemia (B-PLL)

Deletions of the long arm of chromosomes 11 and 13 are the most frequent structural chromosome aberrations in various types of lymphoproliferative disorders. However, these regions have not been studied so far in B cell prolymphocytic leukemia (B-PLL). We have investigated the incidence of 13q deletions in 18 B-PLL cases by fluorescence in situ hybridization (FISH), using molecular probes for the RB1 and D13S25 loci. Chromosome 11q deletions were evaluated by FISH using the yeast artificial chromosome (YAC) clone 755b11 from the chromosome 11q22.3-q23.1 region, which has been previously shown to be deleted in 20% of cases of chronic lymphocytic leukemia. Chromosome 11q23 deletions were found in 7/18 (39%) cases of B-PLL. Monoallelic loss of RB1, D13S25 and BRCA2 was present in 10/18 (55%), 6/18 (33%) and 3/18 (16%) of the cases, respectively. All the cases with D13S25 and BRCA2 deletion showed RB1 loss. Deletions of 13q14 and 11q23 are frequent chromosome aberrations in B-PLL and, in contrast to CLL, there is a preferential loss of RB1 with respect to the D13S25 locus suggesting that allelic loss of the RB1 gene may play a role in the pathogenesis of B-PLL.

Morphological and immunophenotypic features of chronic lymphocytic leukemia

In this review, we summarize the morphological features and immunophenotypic profile of chronic lymphocytic leukemia (CLL) cells, discuss the value of these investigations as front line diagnostic tests, and emphasize their correlation with the clinical features, disease progression, molecular genetics and pathogenesis of CLL. In CLL, the morphology of the circulating cells is characteristic and typical in the majority of cases. However, 15% of patients, either at diagnosis or during the course of the disease, show atypical morphology reflected by either (1) an increased (> 10%) number of circulating prolymphocytes, designated CLL/PL, or (2) an increased (> 15%) number of circulating lymphoplasmacytic and cleaved cells, designated 'atypical' CLL. There is strong evidence of a close association between atypical morphology (CLL/PL) and atypical (CLL) and clinical features, e.g. disease progression, advanced stage and survival, molecular genetics, particularly trisomy 12, but also the rare cases with t(11;14) or t(14;19), p53 abnormalities, unmutated immunoglobulin (Ig) VH genes and origin of the cell (naive, pregerminal center cell). CLL cells have a distinct immunological repertoire different from that of other lymphoproliferative disorders. The typical CLL phenotype is CD5+, CD23+, FMC7-, weak expression of surface Ig (sIg) and weak or absent expression of membrane CD22 and CD79b. The latter marker identifies an extracellular epitope of the B-cell receptor (BCR) beta chain and its weak or absent expression in CLL may derive from the expression of a truncated form. This, together with the low expression of CD22, might explain the abnormal signal transduction of CLL cells similar to that of anergic B lymphocytes. Because no single marker is specific for CLL, a composite phenotype considering this set of 5 or 6 markers compounded into a scoring system helps to distinguish CLL from the other B-cell malignancies. Immunophenotypic analysis has also been shown to be useful for minimal residual disease detection and adds valuable prognostic information because the expression of certain markers, such as FMC7 or CD38, seems to be associated with a poor outcome. In addition, CLL cells express a variety of Bcl-2 family proteins with a profile that favors inhibition of apoptosis which, together with the interaction with microenvironmental (e.g. stromal) cells and the release of cytokines, explains the long life span and subsequent accumulation of CLL cells in various organs. Despite controversies relating to the expression of adhesion molecules (selectins and integrins) in CLL cells, it appears that some of these molecules do play a role in the pathogenesis, biology and clinical patterns of the disease. In conclusion, morphology and immunophenotype are the two essential investigations, which must be carried out in all cases of CLL. Both provide relevant information in terms of diagnosis, course of the disease, prognosis and pathogenesis.

Follicular lymphoma. A series of 11 patients with minimal or no treatment and long survival

Follicular lymphoma is the commonest low-grade lymphoma. Its indolent nature even in advanced stages and the failure of conservative or aggressive treatments to achieve a cure have questioned the need for immediate treatment. Eleven patients with follicular lymphoma who had minimal or no treatment were retrospectively reviewed. Median age was 44 years. Staging was: I (4), III (6) and IV (1). Eight were confirmed to have follicular lymphoma of whom six did not receive treatment at presentation. Four of these patients remain in remission after 14 to 30 years of follow-up and the other two have relapsed after 10 and 13 years of follow-up, respectively. Two patients who were treated at diagnosis remained disease free for 18 years. Three patients had diffuse large cell lymphoma on review. They received no treatment, radiotherapy or chemotherapy and have been in remission for 36, 14 and 23 years respectively. The overall survival is 58% at 30 years, and median survival has not been reached for the whole group. Observation seems to be a valid alternative to treatment in patients with stages I to III until signs of progression.

Effect of lamivudine on human T-cell leukemia virus type 1 (HTLV-1) DNA copy number, T-cell phenotype, and anti-tax cytotoxic T-cell frequency in patients with HTLV-1-associated myelopathy

Patients with human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) typically have a high HTLV-1 proviral load in peripheral blood mononuclear cells and abundant, activated HTLV-1-specific cytotoxic T lymphocytes (CTLs). No effective treatment for HAM/TSP has been described so far. We report a 10-fold reduction in viral DNA for five patients with HAM/TSP during treatment with the reverse transcriptase inhibitor lamivudine. In one patient with recent-onset HAM/TSP, the reduction in viral DNA was associated with a fall in the frequency of CTLs specific to two peptides in the immunodominant viral antigen Tax. The half-life of peripheral blood mononuclear cell populations was estimated from changes in viral DNA copy number, CTL frequency, reduction in CD25 expression, and the loss of dicentric chromosomes following radiation-induced damage. Each of these four different techniques indicated a cellular half-life of approximately 3 days consistent with continuous lymphocyte replication and destruction. These results indicate that viral replication through reverse transcription significantly contributes to the maintenance of HTLV-1 viral DNA load. The relative contribution of proliferation versus replication may vary between infected people.

Impact of immunophenotyping on management of acute leukemias

BACKGROUND AND OBJECTIVE

The diagnosis of acute leukemias (AL) requires a multiparametric approach in order to apply risk-adapted therapeutic protocols and appreciate the potential outcome of any given patient. Blast cells immunophenotyping is a key test in this issue, yet the information provided by immunophenotyping has become staggering, and it may be difficult to identify relevant characteristics clearly. This manuscript provides a critical review of the literature regarding the importance of immunophenotyping in acute leukemia diagnosis and management. DATA SOURCES AND METHODS The information given here is based on the experience of the authors, on their literature files and on additional material retrieved through articles and reviews covered by the Institute for Scientific Information (ISI) and the Medline database. Studies with proper definition of the patients and sufficient information regarding follow-up were considered.

RESULTS

Immunophenotyping allows an early confirmation of AL diagnosis and establishes lineage assignment. Adequate and comprehensive panels of monoclonal antibodies also allow detection of aberrant immunophenotypic profiles of prognostic value or of use in detecting minimal residual disease. A number of unusual immunophenotypic features are also associated with prognosis. The development of new antibodies, new insights in the functional properties of differentiation antigens, and the quantimetric approach of immunophenotyping will keep this field changing. Moreover, as therapeutic protocols evolve, some earlier results need to be reconsidered.

INTERPRETATION AND CONCLUSIONS

Immunophenotyping, together with cytologic, karyotypic and molecular approaches, retains a crucial place in the diagnosis and management of acute leukemias. It remains a rather specialized approach and should be interpreted in a multidisciplinary perspective, considering for each patient the idiosyncrasies possibly relevant to prognosis.

FISH analysis for BCL-1 rearrangements and trisomy 12 helps the diagnosis of atypical B cell leukaemias

We have investigated the diagnostic value of fluorescence in situ hybridisation (FISH) to detect t(11;14) and trisomy 12 in 53 cases with a B cell leukaemia difficult to classify on clinical and laboratory grounds. These cases were initially diagnosed by morphology and immunophenotype and in 33 of them, on tissue histology, as follows: chronic lymphocytic leukaemia (CLL), 20, 18 of them with atypical features; B cell prolymphocytic leukaemia (B-PLL), two; mantle-cell lymphoma (MCL), 15; splenic lymphoma with villous lymphocytes (SLVL), five; lymphoplasmacytic lymphoma, six; follicular lymphoma, one and, four cases remained unclassifiable. FISH demonstrated BCL-1 rearrangement in the circulating cells from 15 cases classified as: MCL (10), atypical CLL (three) and B-PLL (two). A definitive diagnosis of MCL was made on review of the spleen histology in one out of the three atypical CLL with BCL-1 rearrangement. Trisomy 12 was detected in eight cases which included four atypical CLL, one typical CLL, two MCL and one unspecified B cell lymphoma by histology and morphology. One of the MCL had both trisomy 12 and BCL-1 rearrangement and the other was CD5+, CD23+ and had a CLL score of 3, suggesting the latter diagnosis. Our findings demonstrate that FISH analysis is useful to clarify the nature of the disease in patients presenting with a B cell leukaemia in which the diagnosis is difficult by conventional methods. FISH established with certainty the diagnosis of MCL by showing BCL-1 rearrangement in over two-thirds of cases in which this was suspected, including blastoid forms, and confirmed the diagnosis of most cases of atypical CLL.

p53 gene deletion and trisomy 12 in hairy cell leukemia and its variant

The deletion or mutation of the p53 tumour suppressor gene on chromosome 17p13 is known to be associated with aggressive disease in several B-cell malignancies. The present study describes the p53 gene status in 20 cases of hairy cell leukemia (HCL) and in 12 cases of its morphological variant (HCL-V) by fluorescence in situ hybridization (FISH). A high incidence of p53 deletion was found in both diseases (75-100% of cases). However, a significant difference was observed between the proportion of cells with p53 deletion in HCL-V cases (mean 31%) and HCL cases (mean 12%) P value < 0.01. The observed difference correlates with the well known tendency for transformation and poor response to therapy in HCL-V and seven cases of HCL-V with greater than 22% of cells with p53 deletion showed features of disease progression and transformation. Trisomy 12 was present in 8.5% of the cells in one case of HCL-V and in 6-8% of cells in three cases of HCL.

HTLV-I induced intestinal lymphoma

We document an unusual case of HTLV-I positive adult T-cell leukaemia lymphoma (ATLL) in a 25 year old Chilean patient who presented with primary small intestinal involvement and during evolution developed a leukaemic phase. Duodenal biopsy showed infiltration by pleomorphic lymphoid cells with a CD45RO+ CD20- phenotype. Circulating lymphocytes had a convoluted nucleus and displayed a mature T-cell phenotype: CD2+, CD3+, CD4+, CD8-, CD25+, HLA-Dr+. HTLV-I serology was positive and HTLV-I retroviral sequences were demonstrated by PCR in the tissue. The patient was treated with chlorambucil and is well, disease free five years from diagnosis. Intestinal lymphoma as initial manifestation of ATLL is extremely uncommon, but when a T-cell lymphoma is detected in this localisation, in patients from a HTLV-I endemic area, retroviral studies are recommended in order to exclude an association with this retrovirus.