The MEC1 and MEC2 lines represent two CLL subclones in different stages of progression towards prolymphocytic leukemia

The EBV carrying lines MEC1 and MEC2 were established earlier from explants of blood derived cells of a chronic lymphocytic leukemia (CLL) patient at different stages of progression to prolymphocytoid transformation (PLL). This pair of lines is unique in several respects. Their common clonal origin was proven by the rearrangement of the immunoglobulin genes. The cells were driven to proliferation in vitro by the same indigenous EBV strain. They are phenotypically different and represent subsequent subclones emerging in the CLL population. Furthermore they reflect the clinical progression of the disease. We emphasize that the support for the expression of the EBV encoded growth program is an important differentiation marker of the CLL cells of origin that was shared by the two subclones. It can be surmised that proliferation of EBV carrying cells in vitro, but not in vivo, reflects the efficient surveillance that functions even in the severe leukemic condition. The MEC1 line arose before the aggressive clinical stage from an EBV carrying cell within the subclone that was in the early prolymphocytic transformation stage while the MEC2 line originated one year later, from the subsequent subclone with overt PLL characteristics. At this time the disease was disseminated and the blood lymphocyte count was considerably elevated. The EBV induced proliferation of the MEC cells belonging to the subclones with markers of PLL agrees with earlier reports in which cells of PLL disease were infected in vitro and immortalized to LCL. They prove also that the expression of EBV encoded set of proteins can be determined at the event of infection. This pair of lines is particularly important as they provide in vitro cells that represent the subclonal evolution of the CLL disease. Furthermore, the phenotype of the MEC1 cells shares several characteristics of ex vivo CLL cells.

[Clinicopathologic study of 15 splenectomy specimens of patients with hairy cell leukemia]

OBJECTIVE

To investigate the clinicopathologic features, diagnosis, differential diagnosis and the prognosis of hairy cell leukemia (HCL).

METHODS

Fifteen splenectomy specimens of HCL patients were investigated retrospectively using HE and immunohistochemistry in correlation with the follow-up information.

RESULTS

(1) The male to female ratio was 2.75:1, age ranged from 36 to 68 years with a median of 47 years. The most consistent clinical feature at presentation was marked splenomegaly (100%). Other symptoms included anemia (80.0%), thrombocytopenia (60.0%), leucocytosis (53.3%), pancytopenia (20.0%) and the absence of B-symptom. (2) The proportion of hairy cells was (14.6 +/- 7.2)% in periphery blood and (47.3 +/- 23.8)% in bone marrow. The positive rate of TRAP assay was 62.5% in bone marrow; 85.7% for TPA test and the detection rate for RLC was 25% by transmission electric microscopy. The frequency of bone marrow involvement was 100%. (3) The average weight of 15 spleens was (3012 +/- 1974) g. The size of 6 spleens ranged from 16 cm x 10 cm x 5 cm to 32 cm x 20 cm x 14 cm. The white pulp of spleen showed a characteristic atrophy feature or even absent due to leukemic infiltration, predominantly involving the red pulp with some sinusoidal pattern. "Blood pool" change was an infrequent feature (3/15 cases). The nuclei of leukemic cells were round (13 cases) or bean-shaped (2 cases), nucleoli inconspicuous or disappeared. The abundant cytoplasm and prominent cell border resulted in a "fried egg" appearance. By immunohistochemistry, leukemic cells were positive for CD45RA, CD20, PAX-5, CD25, CD11c, Annexin A1 and cyclinD1, but negative for CD3 and CD43. (4) 13 cases (86.7%) have been followed-up and all are alive. Among them, 9 cases are living well more than 5 years and 7 more than 10 years.

CONCLUSIONS

Splenomegaly is frequently the first manifestation of patients with HCL and occurred predominantly in the middle to elderly adults. Definite diagnosis of HCL requires a combined histological and immunohistochemical assessment of the splenectomy specimen, bone marrow biopsy and aspirate.

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.

[Clinical and laboratory prognostic parameters for leukemic types of chronic lymphoproliferative diseases]

AIM

The aim of the study was to identify the clinical and laboratory (hematologic, biochemical and morphological) prognostic parameters of chronic leukemic lymphoproliferative diseases (CLLPD).

METHODS

The study included 155 CLLPD patients. Analysis was performed in the overall CLLPD population and separately in a subgroup of patients with B chronic lymphocytic leukemia with variants (B-CLL+V) including typical B chronic lymphocytic leukemia (B-CLL), mixed chronic lymphocytic leukemia and prolymphocytic leukemia (CLL/PLL), and a variant of chronic lymphocytic leukemia with lymphoplasmocytoid differentiation (CLL/IMC). Kaplan-Meier method (Statistica 7.1) was used on survival analysis.

RESULTS

Male patients older than 62 (p=0.03991), female patients (p=0.02871), patients not receiving antitumor therapy on study entry (p=0.01902) and patients not treated for CLLPB upon study entry (p=0.04076) showed better survival rate. Older patient predominated in the group requiring no antitumor therapy (p=0.019247). Analyis of sex distribution yielded an equal male to female ratio in the overall CLLPD population and B-CLL+V subgroup. Mann-Whitney U-test was used to assess the clinical significance of quantitative parameters related to patient age and sex. The level of bilirubin, the size of cervical lymph nodes and doubling of peripheral blood lymphocytosis (DTL) were lower in the group of older patients (>60 years). Men had higher levels of hemoglobin, bilirubin, SGOT and creatinine, and larger spleen and liver. Statistically significant survival differences were recorded for 16 of 20 clinical parameters. Patients older than 60, female patients and patients receiving no antitumor therapy showed better survival. Lower clinical stage according to Rai and Binet and total tumor mass (TTM) lower than 9 indicated better prognosis, whereas patients with spleen enlargement and multiple regions involved with lymph node enlargement showed poorer survival. B-CLL+V patients and patients free from doubling of total tumor (DTM) or of absolute lymphocyte count (DTL) within 12 months had better survival than the overall CLLPD patient population. A statistically significant survival difference was recorded for 5 of 15 bone marrow (BM) parameters tested: normal and less cellular BM puncture specimen, >70% of all lymphatic cells, >16% of atypical lymphatic cells, and >18% of granulocytes in myelogram indicated better prognosis. Poorer disease outcome was associated with interstitial and nodular infiltration found on bone biopsy. Ten of 20 hematologic parameters were found to be statistically significant. Poorer prognosis was associated with red blood cell count <2.5 x 10(12)/L, leukocyte count >100 x 10(9)/L, reticulocyte count >5/10(3) E, hemoglobin <100 g/L and iron <15 mol/L. Better survival was associated with absolute count of total lymphatic cells <100 x 10(9)/L and absolute count of atypical lymphatic cells <5 x 10(9)/L in peripheral blood; <10% of all atypical lymphatic cells, >5.1% monocytes and >10.1% granulocytes in differential blood count. Statistically significant survival differences were found for 10 of 20 biochemical parameters tested. Poorer survival was recorded in patients with LDH >300 U/L, SGOT >24 U/L, calcium <2.3 mmol/L, total protein <66.1 g/L, albumin <40 g/L, alpha2 globulin<5.9 g/L, beta globulin <7.3 g/L, y globulin <9 g/L and IgG <10 g/L. Better prognosis was only indicated by lower levels of IgM (<0.91 g/L).

CONCLUSION

Careful clinical examination is an important step on assessing the extent and progression of the disease, and a major chain on tailoring individualized therapeutic approach, along with clinical stages according to Rai and Binet, CLLPD subtype and progression factors (DTM and DTL). Laboratory parameters (hematologic and biochemical) as objective quantitative parameters obtained by simple venipuncture, in contrast to the 'researcher-dependent' ones, increase the utilization of some of these parameters as risk factors in CLL.

[Acute myeloid leukemia with the morphological characteristics of prolymphocytic leukemia]

To investigate the clinical, cellular morphology, immunophenotype, and cytogenetic characteristics of acute myeloid leukemia (AML) which are very similar to the morphological characteristics of prolymphocytic leukemia (PLL), the morphological features of bone marrow cells from patient were observed by light microscope, the immunophenotypes were detected by flow cytometry, the karyotypes were analyzed by conventional cytogenetic method, the hybridization signals were determined by fluorescence in situ hybridization. The results indicated that the clinical features were in accordance with acute leukemia and the immunophenotyping results showed malignant cells originated from myeloid lineage, while the cytomorphology analysis showed that the blastic cells were more like the lymphoid lineage. Trisomy 8 was found in the patient by cytogenetic study, the patient did not show good response to chemotherapy. In conclusion, acute leukemia has high heterogenicity, which could be defined as AML, but more like lymphocytic origination by morphological study. Immunophenotyping analysis could contribute to the final diagnosis of malignant cells.

High TCL1 expression and intact T-cell receptor signaling define a hyperproliferative subset of T-cell prolymphocytic leukemia

The T-cell leukemia 1 (TCL1) oncoprotein is overexpressed by chromosomal rearrangement in the majority of cases of T-cell prolymphocytic leukemia (T-PLL). In vitro, TCL1 can modulate the activity of the serine-threonine kinase AKT, a downstream effector of T-cell receptor (TCR) signaling. In a series of 86 T-PLL tumors, we show that expression of TCR, and levels of TCL1 and activated AKT are adverse prognostic markers. High-level TCL1 in TCR-expressing T-PLL is associated with higher presenting white blood cell counts, faster tumor cell doubling, and enhanced in vitro growth response to TCR engagement. In primary tumors and TCL1-transfected T-cell lines, TCR engagement leads to rapid recruitment of TCL1 and AKT to transient membrane activation complexes that include TCR-associated tyrosine kinases, including LCK. Pharmacologic inhibition of AKT activation alters the localization, stability, and levels of these transient TCL1-AKT complexes and reduces tumor cell growth. Experimental introduction and knockdown of TCL1 influence the kinetics and strength of TCR-mediated AKT activation. We propose that in T-PLL, TCL1 represents a highly regulated, targetable modulator of TCR-mediated AKT growth signaling.

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.

T-cell prolymphocytic leukemia: An aggressive T cell malignancy with frequent cutaneous tropism

BACKGROUND

T-cell prolymphocytic leukemia (T-PLL), formerly categorized as T-cell chronic lymphocytic leukemia, is a rare and aggressive hematologic malignancy. Although the skin is characteristically involved, it is not a well-recognized entity in the dermatologic literature.

METHODS

Six cases of cutaneous T-PLL are presented from a clinical, light microscopic, and phenotypic perspective.

RESULTS

The patient population comprised 2 women and 4 men, with a mean age of 69.8 years. The disease was associated in all with skin involvement with facial preference; edema, purpura, and lesional symmetry were characteristic. The skin biopsies demonstrated a largely non-epidermotropic angiocentric lymphocytic infiltrate with accompanying hemorrhage. The cells showed irregular- to reniform-shaped nuclei with small nucleoli and eosinophilic rims of cytoplasm. Phenotypic studies revealed three prevailing profiles: CD4 dominant in 4, CD8 dominant in one, and co-expression of CD4 and CD8 in one. CD3 loss was seen in one case. All expressed T-cell leukemia 1 (TCL-1) and CD7; cutaneous lymphocyte antigen expression was discernible in a dot-like perinuclear array. All cases tested excluding one expressed TCL-1 and CD52. In two cases tested, T-cell receptor beta rearrangements were observed. Cytogenetic studies demonstrated a paracentromeric chromosome 14 inversion. Polysomy 8 and MYC amplification was seen in one case, manifesting an aggressive clinical course. Four patients died from their disease within 18 months of diagnosis.

LIMITATIONS

Cytogenetic MYC amplification, FISH, and TCR beta studies were conducted on each of 2 cases, respectively, due to limitations of tissue block samples and/or peripheral blood. cMYC translocation studies were conducted on 3 of the 6 cases, again due to limitations imposed by the tissue samples on the cases. The last case was recently diagnosed and, therefore, long-term follow-up is not possible.

CONCLUSION

T-PLL is a distinctive post-thymic T-cell malignancy with frequent cutaneous tropism. A diagnosis is possible in almost all cases based on characteristic clinical, light microscopic, phenotypic, and cytogenetic features. While a chromosome 14 inversion is highly characteristic, additional inherent cytogenetic differences, such as trisomy 8 with CMYC over-amplification, may account for some case to case variation in clinical course.

T-Cell Prolymphocytic Leukemia: A Single-Institution Experience

BACKGROUND

T-cell prolymphocytic leukemia is an uncommon, aggressive, mature T-cell leukemia characterized by proliferation of T-cell lymphocytes. The recent availability of modern immunophenotypic and molecular tools has allowed a better distinction of this disorder from its B-cell counterpart and other mature T-cell leukemias.

PATIENTS AND METHODS

The clinical, pathologic, and cytogenetic features of 57 patients with T-PLL who were evaluated at the Department of Leukemia, M. D. Anderson Cancer Center (MDACC) from 1986 to 2004 were examined.

RESULTS

The most common cytogenetic abnormality was inv(14)(q11;q32), which was present in 7 patients. In all 7 patients, this abnormality was associated with other chromosomal aberrations. Patients treated with alemtuzumab at MDACC had a significantly better response rate (P = 0.02) and survival rate (P = 0.002). There were no significant differences in survival based on Tcl-1 expression or different patterns of CD4 and CD8 expression.

CONCLUSION

Treatment with alemtuzumab results in higher response rates and a better survival rate in patients with T-cell prolymphocytic leukemia.

T- cell prolymphocytic leukemia - a rare case

T- cell Prolymhocytic leukemia (T-PLL) is a rare mature post-thymic T-cell malignancy that is usually reported in the elderly and follows an aggressive course. A 68 year old male presented with a history of weakness and weight loss of two months duration. Clinical examination revealed pallor, enlarged cervical and axillary lymph nodes and splenomegaly. He also had a maculo- papular skin rash. There was marked leucocytosis, anemia and thrombocytopenia (WBC 445 x 103 sub/ml, Hb 8.5 gm/dl, Platelet 25 x 103 sub/microl) with 60% prolymphocytes in the peripheral blood. Bone marrow was hypercellular with an excess of prolymphocytes. Flow cytometric analysis of the bone marrow showed positivity for CD2, CD3, CD4, CD5 and CD 7. T- PLL is a rare T cell disorder with characteristic clinical and laboratory features. Currently, no optimal treatment exists although there has been some success with 2'- deoxycoformycin or Campath-1H.

An indolent case of T-prolymphocytic leukemia with t(3;22)(q21;q11.2) and elevated serum beta2-microglobulin

We report a novel case of T-prolymphocytic leukemia, small cell variant, associated with complex cytogenetic findings including t(3;22)(q21;11.2) and elevated serum beta2-microglobulin. The diagnosis is based on morphologic, immunophenotypic, cytogenetic, and molecular analysis of peripheral blood and bone marrow. In contrast to most reported cases of T-prolymphocytic leukemia, this patient did not present with lymphadenopathy or organomegaly. Moreover, only a moderate leukocytosis (25.3 x 10(3)/microL) was evident at presentation. In the absence of any specific treatment, the patient is doing well, with a stable white blood cell count 12 months following presentation. Further investigation may be warranted to determine whether the unusual cytogenetic findings and elevated serum beta2-microglobulin are associated with the indolent clinical course in this patient.

Histopathology of the spleen in T-cell large granular lymphocyte leukemia and T-cell prolymphocytic leukemia: a comparative review

We review retrospectively the spleen histology in 8 patients with T-cell large granular lymphocyte (LGL) leukemia and 4 with T-cell prolymphocytic leukemia (T-PLL) to identify characteristic patterns of involvement and to distinguish such patterns from those described in other low grade B- and T-cell malignancies. Moderate splenic enlargement with red pulp expansion due to lymphocytic infiltration was characteristic of LGL leukemia. Abnormal lymphocytes expressed cytotoxic granule proteins and were consistently CD45RO and CD5 negative in contrast to normal red pulp T cells. This infiltration respected anatomic boundaries with encroachment but no invasion of white pulp areas. Unlike in hairy cell leukemia, the main differential diagnosis for red pulp lymphocytosis, the white pulp was not only preserved in T-cell LGL leukemia but showed germinal center hyperplasia with expansion of the mantle zones. By comparison, T-PLL spleens showed marked red pulp lymphoid infiltration by medium-sized cells with irregular nuclei and prominent eosinophilic nucleoli. T-PLL lymphocytes, unlike LGLs, were more invasive, infiltrating the spleen capsule as well as white pulp areas. T-cell prolymphocytes did not express cytotoxic granule proteins or NK-cell markers, were CD5+, CD45RO+ like normal spleen T cells, were CD2+, CD3+, CD45+, CD43+, TCRbeta+, but CD25-, CD30-, ALK-1-, TRAP-, DBA44-, and TdT-. Expression of CD4 and CD8 in these cells mirrored that of circulating T-PLL cells. These observations on the morphologic and immunohistochemical appearances of the spleen in T-cell LGL leukemia and T-PLL may aid diagnosis of these uncommon T-cell disorders, particularly T-cell LGL leukemia, where presentation may be cryptic and where unique pathognomonic features, are absent.

Burkitt-type acute leukemia in a patient with B-prolymphocytic leukemia: evidence for a common origin

Burkitt-type acute leukemia cells were present in the bone marrow of a patient with B-prolymphocytic leukemia diagnosed from peripheral blood cell morphology. Immunophenotype analysis confirmed morphological patterns. Cytogenetic and fluorescence in situ hybridization (FISH) analysis showed an identical t(8;22)(q24;q21) with MYC locus rearrangement in blood and bone marrow cells, with additional chromosome abnormalities in the bone marrow. In addition, the loss of one copy of the TP53 gene and identical IGH DNA clonal rearrangements were shown with FISH and polymerase chain reaction analysis respectively in the two types of leukemic cells. These data indicated the common origin of the two coexisting leukemias and are the first example of such occurrence in a leukemic patient.

Small cell variant of T-cell prolymphocytic leukemia with a gammadelta immunophenotype

T-cell prolymphocytic leukemia (T-PLL) is a rare postthymic T-cell disorder. The disease is characterized by lymphadenopathy, splenomegaly, skin lesions, a high white blood cell count, and an aggressive clinical course. The small cell variant of T-PLL occurs in approximately 20% of patients. Most T-PLL patients express membrane T-cell receptors (TCR) of the alphabeta phenotype. The diagnosis of small cell variant T-PLL in a 56-year-old woman was based on the findings of abnormal lymphocytosis, immunophenotype, lymphadenopathy, and aggressive clinical behavior. Immunophenotype analysis showed that lymphocytes were positive for CD2, CD3, CD5, CD7, CD8, and TCR gammadelta antigens and negative for CD1a, CD4, and TCR alphabeta antigens. Southern blot analysis revealed rearrangement of the TCR Jgamma and Jdelta-1 genes. A cytogenetic study of peripheral blood showed a normal karyotype. T-PLL with a TCR gammadelta phenotype is very rare. This case was typical T-PLL except for the morphologically small cell type and the lack of the typical chromosome aberration. If cases accumulate in the future, the specific features of the gamma8 type of T-PLL will become clearer.

T-cell prolymphocytic leukemia involving extramedullary sites

T-cell prolymphocytic leukemia (T-PLL) can involve extramedullary sites, but the diagnosis is usually established by examination of blood and bone marrow. As a result, the histologic findings at extramedullary sites are poorly documented in the literature. We describe 19 extramedullary biopsy specimens from 14 patients with T-PLL. Skin (n = 10) was the most common site biopsied. T-PLL surrounded dermal blood vessels and appendages (n = 6), diffusely replaced dermis (n = 3), or formed a subcutaneous mass (n = 1). Other extramedullary sites included liver and lymph nodes (3 each) and spleen, lung, and cecum (1 each). In liver and lymph nodes, the neoplasm predominantly involved portal tracts and paracortex, respectively. Cytologically, the T-PLL cells were round (n = 16) or Sezary cell-like (n = 3). Nucleoli were observed in a subset of cells in 8 specimens and were prominent in 3 specimens. Immunostaining for T-cell leukemia-1 (TCL-1) was positive in specimens from 9 (64%) of 14 patients. We conclude that the prolymphocytoid features of T-PLL cells can be difficult to detect in routinely stained sections of extramedullary biopsy specimens. TCL-1 expression can aid in diagnosis at extramedullary sites.

Development of malignant mesothelioma during treatment for prolymphocytic leukemia: is asbestos or simian virus 40 a link?

A patient with a history of heavy asbestos exposure presented with B-prolymphocytic leukemia/lymphoma (B-PLL). Soon after, he developed rapidly progressing malignant peritoneal mesothelioma. The concurrent development of both relatively uncommon diseases raised the possibility that a common causative factor might exist. Since asbestos, simian virus 40 (SV40), or both have been associated with lymphoproliferative disease and mesothelioma, we investigated both possible links in our patient. Imaging studies provided evidence for asbestos exposure because bilateral pleural plaques were identified. Tissues from bone marrow (involved with B-PLL) and from a peritoneal nodule (involved with mesothelioma) were examined for SV40 DNA using polymerase chain reaction (PCR): no SV40 DNA was detected. We conclude that asbestos remains the sole possible connection to both malignancies in this patient. It seems possible that fludarabine, an immunosuppressive chemotherapy, accelerated the occurrence and progression of malignant mesothelioma during the therapy for his B-PLL.

Effect of alemtuzumab on neoplastic B cells

BACKGROUND AND OBJECTIVES

The therapeutic antibody alemtuzumab is directed against the CD52 molecule and is used for the treatment of B-cell lymphocytic leukemia (B-CLL). We investigated the mechanism of action of this antibody in vitro against different neoplastic B cells and compared it to the anti-CD20 antibody rituximab.

DESIGN AND METHODS

Complement-mediated cytotoxicity assays were performed on freshly isolated neoplastic cells using human serum as the source of complement. Antibody-dependent cellular cytotoxicity (ADCC) was evaluated by chromium release assays, using peripheral blood mononuclear cells as effector cells, before and after 2 days of culture with interleukin-2 (IL-2).

RESULTS

Alemtuzumab lysed cells from the 23 B-CLL samples through complement activation (mean 80%) much more efficiently than rituximab did (mean 16%), presumably because of the higher expression of CD52 than of CD20. All other leukemic B cells, including 1 prolymphocytic leukemia, 2 hairy cell leukemias and 6 B-non Hodgkin's lymphomas were effective targets for both antibodies, with 88% and 85% mean lysis, respectively. Both CD52 and CD20 were highly expressed in these cells. In contrast, most neoplastic B cell samples were poorly lysed through ADCC using freshly isolated peripheral blood mononuclear cells as effectors with either monoclonal antibody and regardless of target antigen levels. ADCC was, however, significantly increased in all cases by culturing the effector cells with IL-2 for 2 days.

INTERPRETATION AND CONCLUSIONS

Complement-mediated lysis is likely to be an important mechanism of action of alemtuzumab in B-CLL and combination with IL-2 may increase this antibody's efficacy through ADCC. Mature neoplastic B cells other than B-CLL express high levels of CD52 and are good targets for alemtuzumab-mediated cytotoxicity.

Conjunctival involvement with T-cell prolymphocytic leukemia: report of a case and review of the literature

T-cell prolymphocytic leukemia is a rare and highly aggressive hematological neoplasm. A patient with T-cell prolymphocytic leukemia presented with bilateral perilimbal conjunctival infiltrates. Conjunctival biopsy showed aggregates of large atypical lymphocytes in the substantia propria with a concentration of atypical cells in the perivascular areas. Immunophenotyping of the malignant cells identified an abnormal clonal T-cell population consistent with T-cell prolymphocytic leukemia. A literature review of all reports of conjunctival involvement with leukemia was performed. The three cases of ocular prolymphocytic leukemia, including the one case of ocular T-cell prolymphocytic leukemia, are discussed in detail as well as 14 reported clinical cases of biopsy-proven conjunctival leukemia. The majority of cases occurred in the setting of acute leukemia, and conjunctival involvement was frequently a presenting sign of the disease or signified disease relapse. Conjunctival involvement with leukemia was consistent with good visual acuity; however, it portended a poor prognosis.

Discrimination of chronic lymphocytic leukemia (CLL) and CLL/PL by cytomorphology can clearly be correlated to specific genetic markers as investigated by interphase fluorescence in situ hybridization (FISH)

Although interphase fluorescence in situ hybridization (FISH) is routinely used in chronic lymphocytic leukemia (CLL), differences in the chromosomal pattern with respect to morphological subtypes of CLL (typical CLL, CLL/PL, PLL) are still under debate. We studied 153 patients with CLL and correlated cytomorphology on peripheral blood stains with FISH analysis and other prognostic markers. The percentage of prolymphocytes was calculated as a continuous variable and followed published thresholds in parallel while being correlated to FISH analysis. Higher percentages of prolymphocytes were associated significantly with deletion of 17p13. Deletion of 17p13 was most frequently observed in patients with more than 30% prolymphocytes. Trisomy 12 was found mainly in cases with 6-30% prolymphocytes. The percentage of prolymphocytes did not correlate with deletions of 11q23 or with 13q14 abnormalities. In conclusion, we suggest that further research focus on the percentage of prolymphocytes in CLL. Doing so, biologically relevant thresholds for the percentages of prolymphocytes in the peripheral blood and their association to underlying genetic markers could be investigated together with other biologically and especially prognostic markers.

Translocation (8;14)(q24;q32) as the sole cytogenetic abnormality in B-cell prolymphocytic leukemia

B-cell prolymphocytic leukemia is a relatively rare lymphoproliferative disorder. No specific cytogenetic abnormality has yet been associated with it. The most common translocation reported in patients with this disease is t(11;14)(q13;q32). We describe the case of a patient with B-cell prolymphocytic leukemia and a hitherto unreported genetic translocation (8;14)(q24;q32) as the sole genetic abnormality, classically seen in patients with B-cell acute lymphoblastic leukemia/Burkitt lymphoma. This patient presented with an asymptomatic leukocytosis and splenomegaly. Her marrow showed lymphoid hyperplasia, with immunophenotyping consistent with prolymphocytic leukemia; however, t(8;14)(q24;q32) was the only cytogenetic aberration with both standard karyotyping and fluorescence in situ hybridization analysis.

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.

T-cell prolymphocytic leukemia with der(11)t(1;11)(q21;q23) and ATM deficiency

T-cell prolymphocytic leukemia (T-PLL) is a rare mature T-cell malignancy and is similar to a mature T-cell leukemia seen in some patients with ataxia telangiectasia, which is a recessive hereditary chromosomal instability syndrome caused by mutations of the ataxia telangiectasia mutated (ATM) gene located on 11q23. Intriguingly, recent studies have strongly implicated ATM in the pathogenesis of T-PLL as a tumor suppressor gene, because biallelic inactivation of ATM is frequently observed in this disease; however, translocations involving 11q23 have rarely been reported in T-PLL. We report here a case of T-PLL with der(11)t(1;11)(q21;q23). Southern blot analysis did not reveal any abnormality of ATM, nor of MLL, which is also located on 11q23 and is involved in t(1;11)(q21;q23) in acute myelomonocytic leukemia. Northern blot analysis further showed that the ATM transcript of normal size is expressed in the leukemic cells at a level higher than that in normal peripheral blood lymphocytes. Western blot analysis, however, revealed that expression of ATM in the leukemic cells is much lower than that in normal lymphocytes. These results imply that translation of the ATM transcript is impaired or that the ATM protein is highly unstable in the leukemic cells, thus suggesting the presence of nucleotide changes in both alleles.

Involvement of central nervous system in prolymphocytoid transformation of chronic lymphocytic leukemia

We report a rare case of involvement of the central nervous system (CNS) by chronic lymphocytic leukemia (CLL). A 68-year-old man with prolymphocytic variant of B-CLL (CLL/PLL), develops CNS involvement with headache and vomiting. Computed tomography of the head showed no abnormalities. The cerebrospinal fluid (CSF) revealed numerous lymphocytoid cells of prolymphocytic appearance consistent with findings on the peripheral blood smear. Immunophenotypic analysis demonstrated that the leukemic B cells were positive for CD19, CD20, and HLA-DR, but CD5 was difficult to detect. The patient was treated with intrathecal methotrexate, cytarabine, and hydrocortisone and had improvement in symptoms and CSF findings. Although CNS involvement is an unusual manifestation in CLL, one should be aware of the possibility of this complication in cases presenting with neurological symptoms.

Prolymphocytic leukaemia--report of three cases

Prolymphocytic leukaemia is a rare subtype of chronic lymphocytic leukaemia. Three such cases were reported here along with clinical details. All these cases were seen in males above 5th decade. These patients showed moderate to massive splenomegaly, inconspicuous lymphadenoapthy in two cases and one with minimal lymphadenopathy. Peripheral smear showed high leukocyte count with more than 55% of prolymphocytes. Bone marrow aspiration showed diffuse involvement and in one with minimal lymphadenopathy, lymphnode aspiration showed prolymphocytes. All the three patients died within a year after diagnosis.

Common clonal T-cell origin in a patient with T-prolymphocytic leukaemia and associated cutaneous T-cell lymphomas

An unusual course was observed in a patient with indolent T-prolymphocytic leukaemia (T-PLL) who subsequently developed mycosis fungoides (Mf), lymphomatoid papulosis (LyP) and cutaneous CD30+ anaplastic large cell lymphoma (ALCL). Polymerase chain reaction analysis demonstrated identical monoclonal T-cell receptor-beta and -gamma gene rearrangements in all the different clinical entities. Furthermore, cytogenetic studies revealed the same aberrant clone with trisomy of chromosome 8 in T-PLL and ALCL cells. This unique observation suggests that in T-PLL, the leukaemic cells might undergo secondary transformation, subsequently resulting in different phenotypes of cutaneous T-cell lymphoma.

Are activation markers (CD25, CD38 and CD103) predictive of sensitivity to purine analogues in patients with T-cell prolymphocytic leukemia and other lymphoproliferative disorders?

T-cell prolymphocytic leukemia (T-PLL) is a rare lymphoproliferative disorder with distinctive clinical and laboratory features. It is often resistant to conventional chemotherapy, but complete or partial responses have been documented with the use of purine analogues. We report on two cases of T-PLL with a slightly different immunophenotype but a remarkably different response to pentostatin. We discuss the possible therapeutic implications of this finding and establish a comparison between immunophenotype and sensitivity to purine analogues in patients with T-PLL and other chronic lymphoproliferative disorders.

Prolymphocytic leukaemia and Hodgkin's lymphoma

We describe a case of B-prolymphocytic leukaemia (B-PLL) who, following a long-lasting remission with fluradabine, developed a Hodgkin's lymphoma (HL) with bone marrow involvement. A 75-yr-old male was found to have a lymphocytosis [white blood cell (WBC) count = 146 x 10(9) L(-1)], small volume axillary lymphadenopathy, and hepatosplenomegaly. The majority of circulating lymphocytes had a round nucleus and prominent single nucleolus. The patient did not respond to chlorambucil and then received fludarabine, achieving a good response lasting for 5 yr, when he manifested with B symptoms and pancytopenia. A diagnosis of HL in the bone marrow was made based on histology (Reed-Sternberg cells) and immunohistochemistry (CD30+, CD15+). Epstein-Barr virus (EBV) studies were negative. The patient was treated with chemotherapy but died 6 months later from disease progression.

[Leukemic meningitis in B-cell prolymphocytic leukemia]

An 84-year-old woman was admitted because of anemia and marked leukocytosis. The white cell count was 237,660/microliter, with 93% abnormal lymphoid cells. The cells had abundant cytoplasm and prominent nucleoli. They were positive for CD 5, 19, 20, 22, 23, HLA-DR, IgM, IgD and kappa chain. Thus, a diagnosis of B-cell PLL was made. Chromosome analysis disclosed a complex karyotypic abnormality. Massive splenomegaly was detected by abdominal computed tomography. No external or internal lymphadenopathy was found. The patient was intermittently treated with etoposide. Although the white cell counts had been suppressed, she refused to take the drug because of side effects. When the white cell count exceeded more than 200,000/microliter again, she developed severe headache, diplopia, nausea, and vomiting. A lumber puncture disclosed infiltration of the prolymphocytes in the cerebrospinal fluid. Though intrathecal chemotherapy alleviated the symptoms and the leukemic cells disappeared, the effects were transient. When the therapy was withheld because of bone marrow suppression, the meningitis recurred and the symptoms progressed. The patient died six months after the initial presentation.

Phenotypic transformation of CD52(pos) to CD52(neg) leukemic T cells as a mechanism for resistance to CAMPATH-1H

Immunotherapy utilizing CAMPATH-1H for patients with chemotherapy-refractory chronic lymphocytic leukemia has yielded encouraging results with many reports of complete remission. Here we report the outcome of two patients with CD4-positive T cell prolymphocytic leukemia treated with CAMPATH-1H. Both patients responded rapidly to treatment and subsequently developed CD4 lymphopenia. One patient remained in complete remission after 14 weeks of treatment. Serial peripheral blood flow cytometry revealed that the CD52 antigen was present throughout treatment. The other patient who was initially CD52-positive, became CD52-negative after 6 weeks of treatment, and developed progressive symptoms of T cell prolymphocytic leukemia. Immunotherapy was stopped, chemotherapy proved futile, and the patient died. This change in phenotype from CD52-positive to -negative during CAMPATH-1H therapy points out a need to develop strategies for maintaining antigenic expression during monoclonal antibody therapy.

In vitro and in vivo effectiveness of arsenic trioxide against murine T-cell prolymphocytic leukaemia

T-cell prolymphocytic leukaemia (T-PLL) is a rare form of mature T-cell leukaemia that is generally resistant to conventional chemotherapy. Mice transgenic for MTCP1 develop leukaemia similar to human T-PLL, providing a model useful for testing therapeutics. We here evaluated the potential effectiveness of arsenic trioxide (ATO) in murine T-PLL. In vitro, ATO consistently reduced the viability of murine T-PLL cells at a clinically achievable concentration (1 micromol/l). The percentage of viable cells after 24 h was 77 +/- 4%, 56 +/- 6%, 31 +/- 7% with 0 micromol/l, 0.5 micromol/l and 1 micromol/l ATO respectively. ATO cytotoxicity was enhanced by ascorbic acid (125 micromol/l). Mice were then treated with ATO (5 microg/g/d intra peritoneally, 5 d per week) or saline for 4 weeks, starting 14 d after tumoral engraftment. The appearance of lymphocytosis and splenomegaly was delayed in the group treated with ATO and survival was significantly prolonged (mean survival in days: 57.6 +/- 0.8 for ATO versus 45 +/- 0 for saline, P < 10-4). No additional effect was observed in vivo by combining ATO with ascorbic acid (500 microg/g/d, 5 d per week, intra peritoneally). These findings provide support for clinical trials to test therapeutic effects of ATO for human T-PLL.

T-cell prolymphocytic leukemia with hemorrhagic gastrointestinal involvement and a new chromosomal abnormality

We report a case of T-cell prolymphocytic leukemia in a 56-year-old woman who exhibited hemorrhaging with gastric involvement as the first manifestation. This patient's condition was diagnosed as T-cell prolymphocytic leukemia based on the findings of lymphocytosis, abnormal immunophenotype, hepatosplenomegaly, lymphadenopathy, and cutaneous involvement. Endoscopic examination of the upper gastrointestinal tract revealed hemorrhage from a gastric lesion with histological involvement. Cytogenetic analysis revealed chromosomal abnormalities, 46,XX,der(1), add(1)(p36), that have not previously been described in T-cell prolymphocytic leukemia. In spite of a transient response to chemotherapy, the patient died 15 months after onset of the disease.

T-cell receptor gammadelta T-cell leukemia with the morphology of T-cell prolymphocytic leukemia and a postthymic immunophenotype

T-cell prolymphocytic leukemia (T-PLL) is a postthymic T-cell neoplasm with a characteristic morphology and heterogeneous immunophenotype. Most cases of T-PLL express membrane T-cell receptors (TCRs) of the alphabeta phenotype. We experienced a 30-year-old man suffering from TCRgammadelta T-cell leukemia with morphology compatible to T-PLL with a postthymic phenotype. He was admitted with skin eruption and pancytopenia. Peripheral blood and bone marrow were occupied with medium-sized lymphocytes, which had moderately condensed chromatin with a single nucleolus and sparse, nongranular basophilic cytoplasm. The immunophenotype was CD1a-, CD2-, CD3+, CD4-, CD5+, CD7+, CD8-, and terminal deoxynucleotidyl transferase negative. Hepatosplenomegaly was absent. He was diagnosed as having T-PLL and was treated with combination chemotherapy. Six months later the leukemic cell became chemoresistant. Although the patient showed transient improvement in response to pentostatin, he died 13 months after the diagnosis. To our knowledge, this is the first case of T-PLL with a TCRgammadelta phenotype.

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.

Skin and gingival lesions in a young woman with B-prolymphocytic leukemia (B-PLL)

B-PLL has not been often associated with diffuse skin involvement or oral lesions. We present a 32 year-old woman in whom skin and gingival manifestations were the prominent clinical signs of disease relapse.

A multicentric study of 41 cases of B-prolymphocytic leukemia: two evolutive forms

B-prolymphocytic leukemia (B-PLL) is an infrequent disease with a poor prognosis. We present the clinical and biological features of 41 patients. Median age was 67 years [42-89] and male-female sex ratio was 2.4. The immunophenotyping revealed B-cell phenotype, with a high level expression of surface IgM and/or IgD in all cases, FMC7+ in 76 % of cases and CD5+ in 67%. Marked spontaneous in-vitro apoptosis was observed in most cases tested (n = 12). The median overall survival time was 5 years and the event-free survival time was 37 months. As detected by univariate and multivariate analysis, the only variables associated with a poor prognosis were advanced age and anemia. No significant difference was observed between de novo PLL (n = 27) and prolymphocytoid transformation of chronic lymphocytic leukemia (n = 14). Two groups of patients were individualized according to their clinical course: patients who died within one year of diagnosis (n = 14) and patients who had a prolonged survival (n = 23) without any treatment in some cases. The comparison between the 2 groups showed that they differed in age (p = 0.01) and anemia (p = 0.02). We also observed that the patients with p53 mutations had a worse clinical outcome. Taken together these data confirm that B-PLL should be regarded as a distinct form of chronic lymphoproliferative disorder and suggest the existence of two patterns of clinical evolution.

Mantle cell leukemia, prolymphocytoid type: a rarely described form

Leukemic manifestations of mantle cell lymphoma are seen in a minority of cases, usually associated with extensive tumor. Usually the neoplastic cells in the peripheral blood resemble mantle cells with a mature chromatin pattern and irregular nuclear contours, or less frequently with a more "blastic" chromatin pattern. A prolymphocytic leukemia with t(11;14)(q13;q32) has previously been reported; however, a complete flow cytometric immunophenotypic profile was lacking. Mantle cell leukemia, prolymphocytoid type with complete flow cytometric data has not previously been described and is the purpose of this report. We report such a case in a 90 year-old female who presented with an elevated white blood cell count. The diagnosis was based on flow cytometric immunophenotyping and the cytomorphology of the peripheral blood combined with cyclin D1 immunohistochemical staining of the bone marrow. We describe our findings and her clinical course in order to heighten awareness of this previously rarely described entity.

[T-cell prolymphocytic leukemia complicated by diffuse large B-cell lymphoma of the stomach]

We describe a case of T-cell prolymphocytic leukemia (T-PLL) in a 76-year-old man, who developed diffuse large B-cell lymphoma (DLBL) of the stomach, a previously unreported occurrence. The patient was referred to our hospital because of marked leukocytosis (40,000/microliter) without clinical symptoms. He was diagnosed as having T-PLL on the basis of the characteristic cell morphology and immunophenotype (CD2+, CD3+, CD4+, CD5+, CD7+, CD8-, CD25-, TCR alpha/beta+), but cytogenetic analysis showed no abnormalities. Fifteen months later, he developed a gastric tumor. Biopsy of the tumor revealed DLBL without features of MALT lymphoma; Helicobacter pylori was not detected. Chemotherapy eradicated the tumor, whereas the T-PLL was resistant to the therapy. The disease showed an indolent course for about 2 years thereafter. Immunological derangement due to T-PLL might have potentiated the development of DLBL in this case.

Differential diagnosis of malignant lymphomas and related disorders by specific pattern of expression of immunophenotypic markers revealed by multiparameter flow cytometry (Review)

The introduction of monoclonal antibodies (mAbs) for cell immunophenotyping and use of flow cytometry with the progressively improving software for multivariate analyses have revolutionized the diagnosis and influenced the classification of hematologic neoplasms. In this review we focus on the practical application of flow cytometry in the diagnosis and classification of malignant lymphomas and related lymphoproliferative disorders with special emphasis on differential diagnosis. A general approach to the utilization of flow cytometry (FC) in hematopathology with an algorithm to diagnose the most common neoplasms is presented. We discuss precursor B-cell neoplasms, mature B-cell neoplasms (SLL/CLL, mantle cell lymphoma, marginal zone lymphoma, hairy cell leukemia, diffuse large B-cell lymphoma, plasma cell dyscrasias and lymphomas with plasmacytic differentiation), precursor T-lymphoblastic leukemia and mature (peripheral) T-cell neoplasms, including T-SLL/PLL, anaplastic cell lymphomas and large granular cell leukemia/lymphoma. The text is accompanied by characteristic FC scatterplots of the discussed entities.