Hybrid form of hairy cell leukemia and chronic lymphocytic leukemia

We report a case with mixed features of hairy cell leukemia (HCL) and chronic lymphocytic leukemia (CLL), which may represent a hybrid form of these two entities. Hairy projections were demonstrated on leukemic cells in the peripheral blood. Surface marker studies of blood and spleen specimens by flow cytometry and immunohistochemistry showed immunophenotype characteristic of HCL, namely, monoclonal IgG-kappa, positive reactions to CD 11c, CD 19, CD 20, Cd 22, and HLA-DR, but negative reactions to CD 3, CD 5, CD 7 and CD 10. The only atypical finding was the absence of CD 25. Immunogenotyping showed rearrangement of heavy-chain and kappa light chain genes. Leukemic cells were also positive for tartrate-resistant acid phosphatase (TRAP). A pseudosinus pattern was demonstrated in the spleen. However, the leukemic cells in the spleen showed atypical cytologic features. Clinically, the patient had generalized lymphadenopathy, high leukocyte counts, Coombs' negative hemolysis, hypoimmunoglobulinemia and IgG-kappa monoclonal gammopathy, features more consistent with CLL than HCL. Although only CD 11c, CD 22, CD 25 and TRAP are characteristic for HLC and CD 5, characteristic for CLL, a panel of eight markers is recommended for the differential diagnosis of HCL, CLL and other low-grade B-cell neoplasms, which may share some common features, making a clear-cut diagnosis difficult.     

Mantle cell lymphoma: a biological and therapeutic paradigm

Recent classifications of non-Hodgkin's lymphomas (NHL) have strictly individualized mantle cell lymphoma (MCL) on the basis of a combination of morphologic, immunophenotypic, and cytogenetic criteria. This clinicopathological entity now appears to be a biological and therapeutic model for the understanding and treatment of hematologic malignancies. The lymphomogenesis of MCL could be explained by a series of genetic abnormalities which occur at different steps of the disease: (1) mutation and/or loss of the ATM gene in centrocytic cells of the follicle mantle of lymph nodes, leading to the loss of ATM function, particularly involved during the V(D)J recombination process; (2) a t(11;14)(q13;q32) translocation which induces a constitutive Bcl-1/PRAD1/CCND1 expression, responsible for cell cycle activation of centrocytic cells characteristic of typical MCL; and (3) secondary additional chromosomal aberrations, such as a p53 mutation, observed in blastic transformation of MCL. Despite the evaluation of a number of treatment modalities, the optimal management of MCL has not yet been defined: (1) conventional and intensified chemotherapy and monoclonal anti-CD20 antibody therapy appear to be effective for the improvement of response rates and event-free or overall survivals; (2) combinations of different treatment modalities must be tested to modify the natural dismal outcome of the disease; and (3) innovative approaches should be developed. From this point of view, all these considerations offer a fine opportunity for extensive medical reflection.     

Sezary cell-like leukemia: a distinct type of mature T cell malignancy

We describe the clinical, ultrastructural, and immunophenotypical characteristics of four cases of an unusual type of T cell leukemia. Clinical features included high WBC, ranging from 26-148 x 10(9)/liter, bone marrow infiltration, splenomegaly, and lymphadenopathy. Skin involvement was not documented at presentation, but it was seen as a terminal event in one patient with a pattern of dermal lymphocytic infiltration different from that usually seen in Sezary syndrome. By ultrastructural analysis, the circulating lymphoid cells were indistinguishable from small Sezary cells in two cases, resembled large Sezary cells in one case, and consisted of a mixture of small Sezary cells and prolymphocytes in the remaining case. The cells from all cases had a mature T cell phenotype, TdT-, CD1a-, CD2+/-, CD3+, CD5+. In addition, the cells were either CD8+, CD4- or CD8+, CD4+ or CD4-, CD8-; and, in only one case, the findings were similar to those of Sezary syndrome cells: CD4+, CD8-, CD7-, BE-2+. In the latter case, serological and immunological assays were positive for HTLV-I while these were negative in two other patients investigated. The features of these patients suggest that Sezary cell leukemia is a distinct clinico-pathological entity although the alternative diagnosis of adult T cell leukemia/lymphoma could not be excluded in the HTLV-I+ case. Sezary cell leukemia appears to be resistant to current chemotherapy regimens and is associated with an aggressive clinical course and short survival.     

Mantle cell lymphoma: Evolving novel options

Mantle cell lymphoma (MCL) represents only 6% of non-Hodgkin's lymphoma but is one of the most active fields of clinical investigation. Front-line therapy appears to benefit from intensification either through high-dose therapy with stem cell transplant consolidation or dose-intense chemotherapy with hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone) and rituximab. Unfortunately, no standard therapy has been defined, and most patients eventually relapse. An impressive number of novel agents are currently being tested, the bulk of which are biologic agents or targeted therapies. Bortezomib is the first in class of proteasome inhibitors and the first new agent to be approved in relapsed/refractory MCL. Other small molecules have shown encouraging activity, including mTOR and Bcl-2 inhibitors, novel antibodies, and new cytotoxic agents. Future trials will also benefit from new molecular approaches through pharmacogenomics.     

Defective provirus form of human T-cell leukemia virus type I in adult T-cell leukemia/lymphoma: clinicopathological features

Human T-cell leukemia virus type I (HTLV-I) is associated with adult T-cell leukemia/lymphoma (ATLL). To examine the relationship between defective HTLV-I proviruses and clinicopathological features, we examined 95 patients with ATLL showing clonal integration of HTLV-I proviral DNA; 77 patients (81%) showed 1 clonal band, 15 (16%) showed 2 clonal bands, and 3 (3%) showed 3 clonal bands. In addition, the defective proviral form was detected in 28 patients (29%): 23 (30%) of the 77 with 1 clonal band, 4(27%) of the 15 with 2 clonal bands, and 1(33%) of the 3 with 3 clonal bands. The numbers of clonal bands had no association with the presence of defective proviruses. We classified the 95 patients with ATLL into four types according to clinicopathological features (smoldering leukemia, chronic leukemia, acute leukemia, and lymphoma types). The distribution of patients with the defective form was not different among these four types. The HTLV-I genomes must have integrated into the human genome DNA and been deleted partially in the cells. The defective form was kept during the clinical stage. All patients with the defective form showed defect of the gag or/and env region. No patient had a defect of the pX region. These data suggest that the pX region of HTLV-I must have played an important role in ATLL genesis.     

Mantle cell lymphoma: Frontline and salvage therapy

Mantle cell lymphoma (MCL) is a therapeutic challenge because of its lower cure rate when compared with other lymphomas such as diffuse large cell lymphoma. The current emphasis in the treatment of newly diagnosed MCL has been on intensifying chemotherapy, but there is no consensus on the need to consolidate with autologous stem cell transplantation. These approaches, however, have not resulted in a cure. Newer strategies include the use of models to aid in tailoring therapy. Likewise, autologous stem cell consolidation does not cure relapsed disease. Because of its known graft-versus-lymphoma effect, allogeneic stem cell transplantation offers a potentially curative option for relapsed MCL. New insights into resistance pathways and new drugs created to inhibit them offer great promise in the treatment of newly diagnosed and previously treated MCL.     

Mantle cell lymphoma: clinicopathologic features and treatments

Mantle cell lymphoma (MCL) accounts for approximately 6% of non-Hodgkin's lymphomas. Patients usually present with advanced disease, with a tendency for extranodal involvement. MCL is an aggressive lymphoma with moderate chemosensitivity, but it remains one of the most difficult therapeutic challenges. Complete response rates to chemotherapy range from 20% to 40%, with median survivals of 2 1/2 to 3 years. Anthracycline-containing regimens do not prolong survival compared with nonanthracycline regimens. Single-agent rituximab (Rituxan) has produced response rates of about 30%, and when combined with an anthracycline-containing regimen, response rates increase to above 90%; however, an impact on survival has not yet been demonstrated. More intensive regimens such as hyperCVAD (hyperfractionated cyclophosphamide [Cytoxan, Neosar], vincristine, doxorubicin [Adriamycin], dexamethasone, methotrexate, cytarabine) with either stem cell transplant or rituximab have been associated with promising results.     

Mantle cell lymphoma: non-myeloablative versus dose-intensive therapy

Mantle cell lymphoma (MCL) is now recognized as an aggressive lymphoma, in which there is frequent development of resistance to chemotherapy and a median survival period of 3-4 years. In recent years, the use of the chimeric monoclonal antibody rituximab, which is directed against the CD20 antigen, has provided new possibilities for the treatment of MCL. Rituximab alone produces overall response rates of 30-33% in patients with MCL, and is also effective at inducing complete responses in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). Furthermore, the addition of rituximab to the regimen of fractionated Hyper-CVAD/MTX-AraC (cyclophosphamide/doxorubicin:vincristine/dexamethasone alternated with methotrexate/cytarabine) has been found to produce responses and relapse-free and overall survival in younger patients that are comparable to those seen with Hyper-CVAD/MTX-AraC plus stem cell transplantation. Despite these promising results, patients aged > 65 years have a poor prognosis, and further studies are required to improve outcomes in this population.     

Donor cell leukemia: a critical review

Approximately 40 cases of DCL have been reported in the literature; cases have been reported after allografts from bone marrow, peripheral blood and cord blood. The study of these cases may provide new insights into the mechanisms of leukemogenesis. Some data suggest that the prevalence of this complication has been under-estimated. Most cases of DCL have occurred following transplantation for leukemia, but there have also been cases reported after transplantation for non-malignant conditions. Various mechanisms have been proposed to explain how DCL arise and are briefly discussed. Additional studies are needed to define with more detail both the true prevalence of this complication and its precise pathogenetic mechanism.     

Relationship between human T cell leukemia virus-II and atypical hairy cell leukemia: a serologic study of hairy cell leukemia patients

Human T cell leukemia virus (HTLV-II) is an infrequently encountered human T cell leukemia virus first isolated from a patient with atypical hairy cell leukemia. Recently, we identified a second patient infected with HTLV-II who had a similar clinical syndrome of atypical hairy cell leukemia associated with peripheral T cell lymphocytosis. HTLV-II was detected by molecular hybridization studies, and more recently, by electron microscopy, in cell lines derived from the patient. Both patients came from the Los Angeles area and had spent several years in Alaska. As opposed to our two patients, 21 patients with more typical cases of hairy cell leukemia were seronegative for HTLV-II. Two additional cases of unusual T cell malignancy linked to HTLV-II have been described by other investigators and bear limited similarity to our index cases. Further studies are necessary to define the spectrum of malignancies linked to HTLV-II and to identify infected individuals for prospective study.     

Hairy cell leukemia: towards a curative strategy

Although not all patients who have HCL require therapy at diagnosis, most eventually need treatment. Historically, splenectomy and interferon-alpha resulted in hematologic responses; however, responses tend to be short. The introduction of purine analogs dramatically changed the prognosis for most patients who hae HCL. It is now considered standard of care to use a purine analog, such as 2-CdA or 2'-DCF, as first-line therapy. This approach results in a high CR rate and prolong DFS. Although both agents yield the same rates of CR and survival, 2-CdA seems easier to administer and my be associated with less toxicity. Despite the excellent results with purine analogs, most patients have MRD detected by sensitive techniques; 30% to 40% of patients eventually relapse and most require further therapy. A repeat course of 2-CdA (or 2'-DCF) will result in CR in approximately 70% of patients. For patients who have relapsed or refractory disease, monoclonal antibody-based therapies are emerging options. Rituximab and BL22 are highly active in this setting. Until BL22 becomes widely available, rituximab is a reasonable choice for salvage therapy; however, the dosing schedule needs to be denied further. The roles of rituximab and BL22 as initial therapy for patients who have previously untreated HCL have not been investigated. Fig. 1 is a suggested algorithm for the treatment of HCL. With the introduction of effective new agents, further studies will determine whether the now achievable prolonged survival will translate into cure.     

MEC1 and MEC2: two new cell lines derived from B-chronic lymphocytic leukaemia in prolymphocytoid transformation

We report the establishment and characterization of two cell lines, MEC1 and MEC2, that grew spontaneously on two subsequent occasions from the peripheral blood (PB) of a patient with B-chronic lymphocytic leukemia (B-CLL) in prolymphocytoid transformation. The patient was EBV-seropositive, his leukemic cells were EBNA negative, but the spontaneously grown cell lines are EBNA-2 positive. In liquid culture MEC1 cells grow adherent to the vessel wall and as tiny clumps; MEC2 cells do not adhere and form large clumps. The doubling time of MEC1 is 40h and of MEC2 is 31h. Both cell lines express the same light (kappa) and heavy chains (mu, delta) as the fresh parental B-CLL cells at the same high intensity, share the expression of mature B cell markers (CD19, CD20, CD21, CD22), differ in the expression of CD23 and FMC7, are CD11a+, CD18+, CD44+, CD49d+, CD54+ and express at high levels both CD80 and CD86. CD5 is negative on MEC1 cells (as on the vast majority of parental cells) and it has been lost by MEC2 cells after several months of culture. The cells have a complex karyotype. The tumour origin of MEC1 and MEC2 has been demonstrated by Southern blot analysis of the IgH loci and by Ig gene DNA sequencing. They use the VH4 Ig family and have not undergone somatic mutations (94.8% homology with germline Ig gene 4-59). Cytofluorographic analysis and RT-PCR reveal that MEC1 and MEC2 overexpress Bcl-2 together with Bax, express large amounts of Bcl-xL and trace amounts of Bcl-xS.     

Mantle cell lymphoma: Therapeutic strategies are different from CLL

Opinion statement In contrast to the typical course of chronic lymphocytic lymphoma and despite an indolent lymphoma-like presentation, the clinical outcome of mantle cell lymphoma (MCL) is dismal, with a median survival time of 3 years and virtually no long-term survivors. Most patients are diagnosed with advanced stage III/IV disease. Although clinical studies did not prove a clear superiority of anthracyclin-containing combinations, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone)-like regimens represent the standard therapeutic approach in MCL. Recent randomized studies have shown a benefit of a combined immunochemotherapy strategy (chemotherapy plus rituximab) increasing the complete and overall response rates, whereas further followup is pending for evaluation of the progression-free and overall survival. In patients younger than 65 years, a dose-intensive consolidation comprising high-dose radiochemotherapy and subsequent autologous stem cell transplantation after a CHOP-like induction results in an improved progression-free survival. However, despite the benefits of this multimodal approach, most patients relapse even after high-dose therapy. The only curative approach is allogeneic stem cell transplantation, which may be adapted to the elderly MCL patient cohort by modified dose-reduced conditioning regimens. Prospective randomized trials remain critical to further improve the clinical course of MCL with the addition of newer treatment modalities, such as radioactively labeled antibodies and targeted therapies (eg, flavopiridol and PS-341).