Powerful strategy for polymerase chain reaction-based clonality assessment in T-cell malignancies Report of the BIOMED-2 Concerted Action BHM4 CT98-3936.

Polymerase chain reaction (PCR) assessment of clonal T-cell receptor (TCR) and immunoglobulin (Ig) gene rearrangements is an important diagnostic tool in mature T-cell neoplasms. However, lack of standardized primers and PCR protocols has hampered comparability of data in previous clonality studies. To obtain reference values for Ig/TCR rearrangement patterns, 19 European laboratories investigated 188 T-cell malignancies belonging to five World Health Organization-defined entities. The TCR/Ig spectrum of each sample was analyzed in duplicate in two different laboratories using the standardized BIOMED-2 PCR multiplex tubes accompanied by international pathology panel review. TCR clonality was detected in 99% (143/145) of all definite cases of T-cell prolymphocytic leukemia, T-cell large granular lymphocytic leukemia, peripheral T-cell lymphoma (unspecified) and angioimmunoblastic T-cell lymphoma (AILT), whereas nine of 43 anaplastic large cell lymphomas did not show clonal TCR rearrangements. Combined use of TCRB and TCRG genes revealed two or more clonal signals in 95% of all TCR clonal cases. Ig clonality was mostly restricted to AILT. Our study indicates that the BIOMED-2 multiplex PCR tubes provide a powerful strategy for clonality assessment in T-cell malignancies assisting the firm diagnosis of T-cell neoplasms. The detected TCR gene rearrangements can also be used as PCR targets for monitoring of minimal residual disease.

Cryptococcal immune reconstitution inflammatory syndrome following alemtuzumab therapy.

Alemtuzumab is a lymphocyte ablative agent that may cause susceptibility to severe opportunistic infections similar to those seen in AIDS. Pathogen-specific immune reconstitution syndromes can complicate antiretroviral therapy and immune recovery in HIV-infected patients. We present the first reported case of immune reconstitution syndrome associated with T lymphocyte recovery after alemtuzumab therapy.

Production of vascular endothelial growth factor in T-cell prolymphocytic leukemia.

We describe a 79-year-old man who had massive pleural effusion and a proliferation of prolymphocytic leukemia cells in the peripheral blood, bone marrow, and pleural effusion fluid. Immunophenotyping of leukemia cells revealed either CD3+CD4+CD8-CD25+ or CD3+CD4+CD8+CD25+. The antibody against human T-cell lymphotropic virus type I was negative. A diagnosis of T-PLL was made. The level of VEGF in the plasma or pleural effusion fluid was very high. Moreover, polymerase chain reaction analysis demonstrated an expression of VEGF mRNA in the leukemia cells, indicating a production of VEGF from leukemia cells and its involvement in the pathogenesis of T-PLL.

Typhlitis as a complication of alemtuzumab therapy.

Alemtuzumab is a humanized monoclonal antibody directed against lymphocytes through the CD-52 receptor, an antigen being found on > 95% of peripheral blood lymphocytes and monocytes, and to a smaller extent on granulocytes. It is an effective immunotherapeutic agent in patients with malignancies such as non-Hodgkin lymphoma, B cell chronic lymphocytic leukemia and T cell pro- lymphocytic leukemia. Adverse side effects are increasingly recognized in patients receiving alemtuzumab, mainly including fever, rigors, nausea/vomiting, skin rash; other severe alemtuzumab-related reactions have also been described, such as lymphopenia and neutropenia leading to both opportunistic (e.g. cytomegalovirus) and non-opportunistic infections. Digestive complications have more rarely been described, i.e.: gastroenteritis and peritonitis. We recently observed a case of particular interest as the patient with T cell prolymphocytic leukaemia treated with alemtuzumab, exhibited symptomatic reactivation of CMV infection and developed subsequently typhlitis.

Prolymphocytoid transformation of follicular lymphoma with coexpression of CD5 and CD10.

Histologic transformation of follicular lymphoma is usually to a diffuse large B-cell lymphoma. We present a rare example of a histologic transformation of follicular lymphoma manifested by prolymphocytoid morphology and an unusual immunophenotype characterized by coexpression of CD5 and CD10. The transformed prolymphocytoid lymphoma was positive for CD5 and CD10 antigens by both flow cytometry and immunohistochemistry. The case also expressed bcl-2 and bcl-6 proteins, and exhibited t(14;18), consistent with derivation from a pre-existing follicular lymphoma. Polymerase chain reaction analysis of the immunoglobulin kappa light chain genes derived from the follicular lymphoma and prolymphocytoid lymphoma showed identical rearranged bands, suggesting clonal identity of the two neoplasms. The basis for coexpression of CD5 and CD10 remains unclear. Because the preceding low-grade follicular lymphoma was positive only for CD10 and did not express CD5, CD5 expression appears to be an acquired phenomenon accompanying the process of histologic transformation in this particular case. Prolymphocytoid transformation, similar to other histologic forms of transformation of follicular lymphoma, appears to accompany clinical progression of disease.

T-cell prolymphocytic leukemia.

T-cell prolymphocytic leukemia (T-PLL) is a rare aggressive post-thymic malignancy with poor response to conventional treatment and short survival. It can readily be distinguished from other T-cell leukemias on the basis of the distinctive morphology, immunophenotype, and cytogenetics. Consistent chromosomal translocations involving the T-cell receptor gene and one of two protooncogenes (TCL-1 and MTCP-1) are seen in the majority of cases and are likely to be involved in the pathogenesis of the disorder. The CD52 antigen is expressed at high density on the malignant T-cells and therapy with alemtuzumab, a humanized IgG1 antibody that targets this antigen, has produced promising results. In relapsed/refractory patients overall and complete response rates have been seen in up to 76% and 60%, respectively. In previously untreated patients, complete remission rates of 100% have been reported. These responses are durable and translate into improved survival for responders. However, relapse is inevitable and strategies using both autologous and allogeneic stem cell transplantation are currently being explored. Additional clinical trials are investigating the use of alemtuzumabin combinations with chemotherapy, either concurrent or sequential. In the future we hope to have a betterunderstanding of how best to integrate these therapeutic approaches to further prolong survival for patients with T-PLL.

Residual T lymphocytes, and not malignant B cells, proliferate upon mitogenic stimulation.

Malignant B cells, derived from hairy cell leukemia (HCL), non-Hodgkin's lymphoma (NHL) or prolymphocytic leukemia were stimulated with mitogens and interleukin 2 after careful depletion of contaminating T cells resulting in final residual percentages of less than 0.1. No proliferation was found as measured by 3H-thymidine incorporation. Subsequently, to the non-T B cell cultures very small amounts of autologous or allogeneic T cells were added, ending up in final concentrations of 0.1, 0.5, 1, or 2% T cells. It appeared that a marked proliferation occurred which had in various coculture combinations to be ascribed to the T cells alone. Moreover, most HCL and other B cell NHL additionally stimulated the T cells, resulting in a further increase in proliferation. We conclude that 3H-thymidine incorporation by malignant B cells such as HCL and B-NHL stimulated with mitogens and IL-2 will in most cases wrongly be attributed to proliferation by the B cells themselves, and instead has to be ascribed to contaminating T cells.

Sezary cell leukaemia: a distinct T cell disorder or a variant form of T prolymphocytic leukaemia?

We report the clinical, ultrastructural, immunophenotypic and virological features of nine cases of a rare type of mature T cell disorder formerly designated Sezary cell leukaemia. All patients presented with lymphocytosis ranging from 12.7 to 133 x 10(9)/l, bone marrow infiltration, splenomegaly and lymphadenopathy. Skin involvement was absent at presentation but developed as a terminal event in two patients, one of whom showed a pattern of dermal infiltration different from that characteristic of Sezary syndrome. Cells from eight cases bore a mature T cell phenotype and electronmicroscopy revealed lymphocytes with cerebriform nuclei resembling Sezary cells. All cases except one were HTLV-I negative. Patients were treated with various chemotherapy regimens but with poor outcome, the median survival being 13 months. Laboratory and clinical data suggest great similarity between Sezary cell leukaemia and T prolymphocytic leukaemia (T-PLL), namely coexpression of CD4 and CD8 (3/9 cases), identical chromosomal abnormalities in the three cases studied (isochromosome 8q plus inversion 14 or t(X;14)(q28;q11)) and a remarkable sensitivity to CAMPATH-1H (complete remission of 21 months' duration in one patient), suggesting that this entity could be considered a variant form of T-PLL. The alternative diagnosis of adult T cell leukaemia/lymphoma could not be excluded in one patient in whom positive HTLV-I serology was documented.

Engraftment of chronic prolymphocytic and T cell leukemia in SCID mice.

Engraftment of human acute leukemia cells in immunocompromised (SCID) mice has resulted in in vivo models for exploration of human tumor biology. Attempts at engraftment of chronic leukemia cells have been generally unsuccessful. We have engrafted cells from three human chronic leukemias in SCID mice. Cell populations were from two patients with chronic lymphocytic leukemia (CLL) and either increased proolymphocytes (CLL-Pro; patient 1), or prolymphocytic transformation (PLL; patient 2) and from a third patient with newly diagnosed T cell CLL. Both fresh and cryopreserved cells were used and were injected intravenously, intraperitoneally, or both, after conditioning with cyclophosphamide. In addition, cells derived from a mouse spleen engrafted with human leukemia were passaged into another mouse. The animals were observed daily for signs of disease or appearance of tumors and sacrificed when terminally ill. At intervals blood samples were obtained and analyzed for the presence of human cells or DNA. Human leukemic cells were demonstrated by polymerase chain reaction (PCR) analysis of the human DQalpha gene or positive staining for human leukocyte common antigen (LCA). The presence of Epstein-Barr virus (EBV)-positive cells was also investigated by PCR analysis. Disseminated tumors developed in most mice inoculated with cells from the first patient, and this was associated with shortened survival times. The methods of administration, use of fresh or frozen samples, or the size of the inoculum had no effect on the development of leukemia. Survival of the mouse receiving passaged cells was similar to mice inoculated with fresh cells. Extensive histologic, immunophenotypic, and DNA studies were performed on organs from mice engrafting with cells from patient 1. PCR analysis for EBV sequences was negative in the mice engrafting from all three cases. The successful engraftment of human CLL-Pro PLL and T cell CLL in SCID mice, and the reproducibility of this effect using frozen cells, will provide a model for exploration of disease biology and for investigations of new drugs or combinations that may be useful in the treatment of CLL.

The immunological profile of B-cell disorders and proposal of a scoring system for the diagnosis of CLL.

We have investigated the role of immunophenotyping in distinguishing between leukemic B-cell lymphoproliferative disorders. Circulating cells from 666 cases were analyzed with a panel of markers by flow cytometry. The diseases included: chronic lymphocytic leukemia (CLL), 400; prolymphocytic leukemia, 22; hairy cell leukemia (HCL), 40; HCL variant, 15; splenic lymphoma with villous lymphocytes, 100; follicular lymphoma, 26; lymphoplasmacytic lymphoma, 25; mantle-cell lymphoma, 20; and large cell lymphoma, 18. On the basis of the most common marker profile in CLL, CD5+, CD23+, FMC7- and weak expression (+/-) of surface immunoglobulin (SmIg) and CD22, we devised a scoring system that gives for each of these five markers a value of 1 or 0 according to whether it is typical or atypical for CLL. Scores range from 5 (typical of CLL) to 0 (atypical for CLL). Application of the scoring system to all the cases showed that 87% of CLL scored 5 and 4 and only 0.4% scored 0 or 1, whereas 89% of other B-cell leukemias and 72% of lymphomas scored 0 or 1; only one case (0.3%) scored 4 and none scored 5 (p < 0.0001). There were no differences between CLL with high and low scores but higher scores were found in cases with more typical morphology (p < 0.0015). Considering each individual marker, there was no single one that distinguished CLL from other diseases, although the most reliable were SmIg intensity and FMC7. The proposed score will facilitate the diagnosis of B-lymphoproliferative disorders and improve their classification.

Proliferation of B cell malignancies in all stages of differentiation upon stimulation in the 'CD40 system'.

Stimulation of the CD40 antigen on normal B cells by crosslinking of anti-CD40 mAbs via their Fc receptor using a Fc gamma RII(CD32)-transfected mouse fibroblast cell line ('CD40 system') results in activation and proliferation. Not only normal B cells, but also malignant B cells fitting in the low-grade malignancy category such as chronic lymphocytic leukemia (CLL), hairy cell leukemia and follicular lymphoma could be induced to proliferation upon CD40 stimulation. Here, the 'CD40 system' has also been used to culture intermediate and high grade malignancies. Proliferation was measured by 3H-thymidine incorporation and cell counting after culture. Time curves showed that at day 7 most cultures were optimal. By flow cytometry, morphology and assessment of light chain restriction the monoclonal nature of the cultured B cells was proven. We confirmed that B cell malignancies with a more slowly evolving course, such as CLL (n=11), PLL (n=5), and low-grade NHL (immunocytoma and follicular cb/cc n=9), could successfully be cultured in the 'CD40 system'. In contrast, four out of seven cases of mantle cell lymphoma did not proliferate. Cases of precursor B lineage ALL (n=7), high grade NHL (n=3) and multiple myeloma (n=10) showed a heterogenous growth pattern. We conclude that the 'CD40 system', although not always successful, is a useful tool to culture a whole variety of B cell malignancies.

[Allogeneic bone marrow transplantation for chemotherapy-resistant T-prolymphocytic leukemia].

A 34-year-old female was referred to our hospital for the evaluation of atypical lymphocytosis. Leukocyte count at diagnosis was 17,900/microl with 58% atypical lymphocytes having a convoluted nucleus and prominent nucleoli. Because the leukocyte count increased to 43,600/microl, the patient was treated with 2'deoxycoformycin followed by CHOP combination chemotherapy. However, both treatments failed to achieve remission. We planned an allogeneic bone marrow transplantation from an HLA-matched unrelated donor. The patient was treated with Ara-C and etoposide before conditioning to decrease the high leukemia burden. After administration of total body irradiation (12 Gy in six fractions) and cyclophosphamide (total dose of 120 mg/kg) unmanipulated marrow cells were infused. Under prevention of GVHD by CsA and short-term MTX, leukocyte engraft was prompt at day 16, and acute GVHD grade II was observed. Because 9.4% of residual recipient type T-cells was seen with STR analysis on day 22, we decreased the dose of Cs'A. After the occurrence of mild acute GVHD, the residual T-cell number decreased. The patient is still in complete remission for up to 22 months after BMT. We conclude that allogeneic SCT is effective for the treatment of T-PLL.

Efficacy of fludarabine, a new adenine nucleoside analogue, in patients with prolymphocytic leukemia and the prolymphocytoid variant of chronic lymphocytic leukemia.

PURPOSE: To describe the results of fludarabine therapy in patients with prolymphocytic leukemia (PLL) and the prolymphocytoid variant of chronic lymphocytic leukemia (CLL-Pro). PATIENTS AND METHODS: Seventeen patients with a diagnosis of PLL or CLL-Pro received fludarabine 30 mg/m2 over 30 minutes daily for 5 days every 4 weeks alone (12 patients), or with prednisone (five patients). Previously defined criteria for response were used. Differences in response rates according to various characteristics were evaluated by chi-square test. RESULTS: Three patients (18%) achieved complete remission, and three (18%) had a partial remission, for an overall response rate of 35%. Responses were durable and occurred in all involved organ sites. Lower response rates were observed in patients with anemia, thrombocytopenia, advanced Rai stages, and primary resistance to prior therapy. Toxicities were minimal except for febrile episodes associated with therapy. CONCLUSION: Fludarabine has shown encouraging results in these patients and deserves further investigation in combination with other active agents, and in the setting of front-line therapy.

Immunophenotypic and idiotypic characterisation of the leukaemic B-cells from patients with prolymphocytic leukaemia: evidence for a selective expression of immunoglobulin variable region (IGV) gene products.

B-cell prolymphocytic leukaemia (B-PLL) is a rare chronic lymphoproliferative disease characterised by a massive splenomegaly associated with a mild or no lymphadenopathy and a high leukocyte count, mostly representing prolymphocytic features. We have studied membrane expression of certain Ig VK and VH gene products in five patients with B-PLL using a panel of monoclonal anti-subgroup and anti-cross-reactive idiotype (CRI) antibodies. Membrane expression of leukocyte-associated markers has also been investigated. The leukaemic cells from four patients expressed VKIII and VKIIIb subgroup and sub-subgroup kappa light chains. The VKIIIb and VHI-associated CRI identified by the monoclonal antibodies (MoAb) 17-109 and G8 were co-expressed in one patient. No B-cells from the patients expressed the VHIII-associated CRI. The same pattern of CRI expression was observed in a serum paraprotein collected from one of the patients. These results suggest a biased selection for the IG VKIII and VKIIIb light chains in B-PLL.

Induction of apoptosis in CD4+ prolymphocytic leukemia by deoxyadenosine and 2'-deoxycoformycin.

The leukemic cells of a patient with CD4+ prolymphocytic leukemia were treated in vitro with 5 microM deoxyadenosine and 60 microM 2'-deoxycoformycin (dCF), an inhibitor of adenosine deaminase (ADA). Following treatment, the leukemic cell dATP level increased to 378 pmol/10(6) cells on day 3, after which the level plateaued. Apoptosis was apparent following 4 h of incubation, and by day 8 34% of the chromatin was fragmented. Apoptosis also occurred in control cells, but to a lesser extent than in drug-treated cells. When the patient was treated with dCF, 4 mg/M2 i.v. the leukemic cell ADA activity was inhibited 24 h following treatment, and the lymphocyte dATP content increased to 303 pmol/10(6) cells by day 6. The lymphocyte count fell 60% in 1 week, but during this time there was no evidence of apoptosis in these cells. Thus, if dCF induces apoptosis in vivo, the effete cells may be rapidly cleared from the circulation and thus elude detection.

Immunological subtypes of childhood acute lymphoblastic leukemia in Bulgaria.

With regards to the geographical variation in acute lymphoblastic leukemia (ALL) distribution, we present data from the immunophenotyping of 171 newly diagnosed cases of childhood ALL in Bulgaria during a 4 year period (1990-1994). On the basis of 17 phenotypic markers the distribution of immunological subtypes was as follows: AUL 4%; Pro-B ALL 13%; common ALL 42%; Pre-B ALL 11%; B-ALL 1%; T-ALL 28% and unclassified 2%. Most of the cases were between 2 and 5 years of age. Common ALL was predominant (53%) in this age group. The male:female ratio was 1.7:1. The frequency of T-ALL (28%) was significantly higher (P < 0.01; t = 3.49) in comparison to that reported for the U.S.A. and West European countries (mean 13%). It was close to the frequency reported by some authors for France (20%), Greece (26%) and south Italy (28.1%). These countries and Bulgaria might form an environmental area with a moderate frequency of T-ALL.

Typical and atypical chronic lymphocytic leukemia differ clinically and immunophenotypically.

We compared the features of 17 cases of atypical chronic lymphocytic leukemia (aCLL) with those of a clinical control group of 24 cases of CLL. Quantitative flow cytometric data, available for 12 cases, were compared with an immunophenotypic control group of 58 cases using a relative fluorescence indexfor CD5, CD23, CD79b, and surface immunoglobulin light chain (sIg). Compared with the clinical control group, patients with aCLL had a higher mean WBC count and a lower platelet count. Patients with aCLL had a significantly higher probability of disease progression. Compared with an immunophenotypic control group of 58 CLL cases, 12 cases of aCLL demonstrated significantly higher expression of CD23. There was no significant difference in expression of sIg, CD79b, or CD5 between the groups. CD38 expression was noted in only 1 (9%) of 11 tested cases; 2 (18%) of 11 cases had trisomy 12. aCLL can be distinguished from typical CLL morphologically, clinically, and immunophenotypically. Atypical morphologic features in CLL seem to be a marker of aggressive clinical behavior.

Chronic prolymphocytoid leukaemia with an unusual immature immunophenotype.

A case of a 58 year old woman with a chronic lymphoproliferative disorder of unusual clinical presentation, disease course, and immunophenotype is presented. At diagnosis she had severe anaemia, moderate lymphocytosis with some cells having prolymphocytoid features and a normal platelet count. A clinical examination yielded negative results. Only anaemia related symptoms were found and the patient became blood transfusion dependent. Both the lymphocytosis and the proportion of prolymphocytoid cells rose insidiously and thrombocytopenia developed later during the course of the disease. Three years later, the patient had a white cell count of 269 x 10(9)/l almost exclusively of prolymphocytoid cells and the bone marrow was diffusely infiltrated. She was refractory to chemotherapy and the anaemia did not improve after treatment with cyclosporine. Lymphoid cells were positive for cytoplasmatic CD3, HLA-Dr, CD34, CD38, CD7, CD56, CD13, CD33 and CD65. Membrane alpha beta and gamma delta T cell receptors (TCRs) were not expressed and the beta chain TCR gene was in germline configuration. Other membrane T, B, natural killer, and myelomonocytic markers were negative. Karyotype analysis was tried several times but metaphases were not obtained, even after stimulation with T cell mitogens.

Levels of expression of CD19 and CD20 in chronic B cell leukaemias.

AIMS: To investigate whether the antigen levels of the B cell lineage markers CD19 and CD20 can distinguish between normal and neoplastic B cells or characterise distinct expression patterns among the chronic B cell leukaemias. METHODS: Peripheral blood cells from 70 patients with B cell disorders and 17 healthy donors were analysed by quantitative flow cytometry. Direct immunofluorescence staining was performed with phycoerythrin conjugated CD19 and CD20 monoclonal antibodies. Standard microbeads with different capacities to bind mouse immunoglobulins were used to convert the mean fluorescence intensity (MFI) values into number of antigen molecules/cell, expressed as antibody binding capacity (ABC). RESULTS: CD19 and CD20 ABC values in leukaemic B cells differed from those of normal blood B lymphocytes. The results identified distinct profiles of CD19 and CD20 expression in the various types of B cell leukaemias. In all leukaemias studied except hairy cell leukaemia (HCL), CD19 expression was significantly lower than the mean (SD) value in normal B cells (22 (7) x 10(3) molecules/cell), as follows: chronic lymphocytic leukaemia (CLL), 13 (7) x 10(3); B prolymphocytic leukaemia (B-PLL), 16 (9) x 10(3); splenic lymphoma with villous lymphocytes (SLVL), 15 (11) x 10(3); mantle cell lymphoma (MCL), 10 (7) x 10(3). In HCL there was strong CD19 expression (38 (16) x 10(3)). In contrast, the level of expression of membrane CD20 was higher than the mean (SD) value in normal B cells (94 (16) x 10(3) molecules/cell) in MCL (123 (51) x 10(3)); B-PLL (129 (47) x 10(3)); SLVL (167 (72) x 10(3)); and HCL (312 (110) x 10(3)); while it was significantly lower (65 (11) x 10(3)) in CLL compared with normal B cells and the other B cell leukaemias. CONCLUSIONS: Quantitative determination of CD19 and CD20 may provide useful diagnostic information for the study of B lymphoproliferative disorders.

Expression of Ki-67 nuclear antigen in B and T cell lymphoproliferative disorders.

AIMS: To determine whether the proliferation rates of tumour cells may relate to prognosis and reflect disease activity. METHODS: Blood mononuclear cells from 155 patients with B cell (n = 120) or T cell (n = 35) chronic lymphoproliferative disorders were tested with the monoclonal antibody Ki-67 by indirect immunoperoxidase or immunoalkaline phosphatase techniques. B cell diseases included chronic lymphocytic leukaemia (CLL), CLL in prolymphocytic transformation (CLL/PL), prolymphocytic leukaemia (B-PLL) and non-Hodgkin's lymphoma (B-NHL) in leukaemic phase. The T cell diseases comprised large granular lymphocyte (LGL) leukaemia, T-PLL, and T-NHL. RESULTS: These showed significantly higher proportions of Ki-67 positive cells in T cell (11.2%) than in B cell (2.9%) disorders (p < 0.001). The highest values were found in NHL of both B and T cell types, particularly when low grade disease transformed to high grade. The lowest percentages of Ki-67 positive cells were found in CLL (1.4%) and LGL leukaemia (1.7%); intermediate values were seen in B PLL (3.3%) and T PLL (5.8%). CONCLUSIONS: There is a positive correlation between prognosis and proliferation rates in chronic B and T cell lymphoproliferative disorders. Estimation of Ki-67 in circulating leukaemic cells could be used to determine prognosis in low grade malignancies.