Improvement of the chronic lymphocytic leukemia scoring system with the monoclonal antibody SN8 (CD79b)

Chronic Lymphocytic Leukemia with t(14;18)(q32;q21) As a Sole Cytogenetic Abnormality

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. The chromosomal abnormality t(14;18)(q32;q21) is most commonly associated with neoplasms of a follicular center cell origin. However, t(14;18) has also been reported in rare cases of CLL.

OBJECTIVE

We describe the clinicopathologic, immunophenotypic, conventional, and molecular cytogenetic features of two rare cases proven to be CLL morphologically and immunologically in which t(14;18) was found as the sole cytogenetic abnormality.

METHODS

Morphologic, flow cytometric analysis and molecular cytogenetic of peripheral blood and/or bone marrow samples were analyzed.

RESULTS

Cytomorphologically, the cells were small mature lymphocytes without any findings that had characteristics of follicular lymphoma (FL) such as indented or clefted nuclei. Immunologic findings were characteristic of typical CLL without expression of CD10. A cytogenetic study revealed the two cases of CLL carrying t(14;18)(q32;q21).

CONCLUSION

We concluded that CLL with t(14;18) is rare and should be differentiated from FL as the therapy is highly diverse between both diseases. Using immunoglobulin heavy chain gene (IGH) probes are important in the workup of patients with suspected CLL and suggest that the IGH probe should be used routinely in all CLL fluorescence in situ hybridization (FISH) panels.

Flow cytometric analysis of SOX11: a new diagnostic method for distinguishing B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma from mantle cell lymphoma

The differential diagnosis between mantle cell lymphoma (MCL) and B-cell chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL) is essential, since MCL usually has a more aggressive clinical course. By flow cytometry both MCL and B-CLL are CD19, CD20 and usually CD5 positive. However, ambiguities in other immune phenotypic markers of these lymphoma entities sometimes complicate the flow cytometric differential diagnosis. We here demonstrate that the transcription factor SOX11, which is highly up-regulated in most MCL, can be analyzed by flow cytometry. SOX11 protein could be consistently detected in ex vivo isolated MCL but not in B-CLL/SLL. Flow cytometry also enabled protein quantification, and SOX11 protein levels correlated with mRNA expression. We suggest that implementing detection of SOX11 in diagnostic flow cytometry would be beneficial for accurate and reliable diagnosis of MCL, especially for distinguishing cases of MCL and B-CLL/SLL with aberrant immune phenotypes, and for cases of rare cyclin D1 negative MCL.

Utility of quantitative flow cytometry immunophenotypic analysis of CD5 expression in small B-cell neoplasms

CONTEXT

The value of assessing CD5 expression in the differential diagnosis of small B-cell neoplasms is well established. Assessment is usually done qualitatively.

OBJECTIVES

To assess CD5 expression levels by quantitative flow cytometry immunophenotyping and to determine possible differences among various small B-cell neoplasms.

DESIGN

We performed 4-color flow cytometry analysis on specimens of peripheral blood and bone marrow aspirate and quantified CD5 expression in various small B-cell lymphomas and leukemias. We also assessed CD5 levels in peripheral blood samples of healthy blood donors.

RESULTS

Cases of chronic lymphocytic leukemia and mantle cell lymphoma had higher levels of CD5 compared with control B cells (P < .001). Cases of marginal zone lymphoma and hairy cell leukemia had CD5 levels similar to control B cells (P = .35 and P = .14, respectively), whereas cases of follicular lymphoma and lymphoplasmacytic lymphoma had significantly lower CD5 levels than control B cells (P < .001 and P = .04, respectively). In B-cell neoplasms, a high level of CD5 expression was correlated with a homogeneous pattern of positive events, whereas lower CD5 levels were correlated with heterogeneous patterns of positive events.

CONCLUSIONS

Using flow cytometric immunophenotypic analysis to quantify CD5 levels can aid in diagnosis. CD5 expression levels are higher in patients with chronic lymphocytic leukemia and mantle cell lymphoma, and expression is observed in a homogeneous pattern, as compared with other B-cell neoplasms that are either negative for CD5 or express CD5 at lower levels with a heterogeneous pattern. However, there is some overlap in CD5 expression levels between a subset of atypical chronic lymphocytic leukemia and marginal zone lymphoma cases.

14q deletions are associated with trisomy 12, NOTCH1 mutations and unmutated IGHV genes in chronic lymphocytic leukemia and small lymphocytic lymphoma

Deletions of the long arm of chromosome 14 [del(14q)] are rare but recurrently observed in mature B-cell neoplasms, particularly in chronic lymphocytic leukemia (CLL). To further characterize this aberration, we studied 81 cases with del(14q): 54 of CLL and 27 of small lymphocytic lymphoma (SLL), the largest reported series to date. Using karyotype and fluorescence in situ hybridization (FISH), the most frequent additional abnormality was trisomy 12 (tri12), observed in 28/79 (35%) cases, followed by del13q14 (12/79, 15%), delTP53 (11/80, 14%) delATM (5/79, 6%), and del6q21 (3/76, 4%). IGHV genes were unmutated in 41/53 (77%) patients, with a high frequency of IGHV1-69 (21/52, 40%). NOTCH1 gene was mutated in 14/45 (31%) patients. There was no significant difference in cytogenetic and molecular abnormalities between CLL and SLL. Investigations using FISH and SNP-array demonstrated the heterogeneous size of the 14q deletions. However, a group with the same del(14)(q24.1q32.33) was identified in 48% of cases. In this group, tri12 (P = 0.004) and NOTCH1 mutations (P = 0.02) were significantly more frequent than in the other patients. In CLL patients with del(14q), median treatment-free survival (TFS) was 27 months. In conclusion, del(14q) is associated with tri12 and with pejorative prognostic factors: unmutated IGHV genes (with over-representation of the IGHV1-69 repertoire), NOTCH1 mutations, and a short TFS.

Possible role of CD22, CD79b and CD20 expression in distinguishing small lymphocytic lymphoma from chronic lymphocytic leukemia

Aim of the study

Flow cytometry has an important role in diagnosis and classification of B-cell lymphoproliferative disorders (BCLPDs). However, in distinguishing chronic lymphocytic leukemia (CLL) from small lymphocytic lymphoma (SLL) only clinical criteria are available so far. Aim of the study was to determine differences in the expression of common B cell markers (CD22, CD79b and CD20) on the malignant lymphocytes in the peripheral blood samples of CLL and SLL patients.

Material and methods

Peripheral blood samples of 56 CLL and 11 SLL patients were analyzed by 5-color flow cytometry on the CD45/CD19/CD5 gate for CD22, CD79b and CD20.

Results

In the samples collected from the CLL patients, CD22 expression was detected in only 20% of patients in the low pattern, while in SLL patients the expression was medium and present in 90.9% of patients (p < 0.0001). For CD79b expression, statistical significance is reached both in the expression pattern, which was low/medium for CLL and high for SLL, and expression level (p = 0.006). The expression of CD20 was counted as the CD20/CD19 ratio. The average ratio was 0.512 in the CLL patients vs. 0.931 in the SLL patients (p = 0.0001).

Conclusions

The pattern of expression and expression level of CD22, CD79b and CD20 in peripheral blood could be used for distinguishing SLL from CLL patients.

CD200 has an important role in the differential diagnosis of mature B-cell neoplasms by multiparameter flow cytometry

BACKGROUND

Multiparameter flow cytometry is a useful tool for the diagnostic evaluation of mature B-cell neoplasms (MBN). Recently, it has been shown that CD200 may improve the distinction between chronic lymphocytic leukemia (CLL; CD200+) and mantle cell lymphoma (MCL; CD200-), but the role of CD200 expression in atypical CLL and other MBN remains to be established.

METHODS

To address this issue, we investigated the expression of CD200 in 159 consecutive cases of MBN.

RESULTS

CD200 was strongly expressed in CLL and was revealed to be an excellent marker to distinguish CLL from MCL, even in cases of atypical CLL. However, lack of CD200 was not an exclusive finding of MCL, being also observed in other MBNs. Furthermore, CD200 was highly expressed in hairy cell leukemia, being useful in the differential diagnosis of lymphomas with villous lymphocytes. Herein, we propose an algorithm to classify CD5+ MBNs based on the expression of CD200, CD11c, heavy chain immunoglobulins, and Matutes score.

CONCLUSIONS

These results expand the understanding of the CD200 expression in MBNs, giving further support for the inclusion of this marker in the routine investigation by flow cytometry.

Chronic lymphocytic leukemia: 2013 update on diagnosis, risk stratification and treatment

DISEASE OVERVIEW

Chronic lymphocytic leukemia (CLL) is the commonest leukemia in western countries. The disease typically occurs in elderly patients and has a highly variable clinical course. Leukemic transformation is initiated by specific genomic alterations that impair apoptosis of clonal B-cells.

DIAGNOSIS

The diagnosis is established by blood counts, blood smears, and immunophenotyping of circulating B-lymphocytes, which identify a clonal B-cell population carrying the CD5 antigen as well as B-cell markers.

PROGNOSIS

Two prognostic staging systems exist, the Rai and Binet staging systems, which are established by physical examination and blood counts. Various biological and genetic markers also have prognostic value. Deletions of the short arm of chromosome 17 (del(17p)) predict resistance to most available therapies.

THERAPY

Patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. For physical fit patients, chemoimmunotherapy with fludarabine, cyclophosphamide and rituximab represents the current standard therapy. For unfit patients, treatment with an anti-CD20 antibody plus a milder chemotherapy (chlorambucil) is currently established as standard treatment. At relapse, the initial treatment may be repeated, if the treatment-free interval exceeds two years. If the disease relapses earlier, alternative therapies such as bendamustine alone or with rituximab, alemtuzumab, lenalidomide, or ofatumumab should be used. Patients with a del(17p) or TP53 should be considered for an allogeneic SCT.

FUTURE CHALLENGES

Several new agents (e.g., ibrutinib, obinutuzumab) hold the potential to change standard of CLL treatment in the next 6-12 months. Therefore, CLL patients should be included into current clinical trials whenever possible.

Very low levels of surface CD45 reflect CLL cell fragility, are inversely correlated with trisomy 12 and are associated with increased treatment-free survival

It has recently been suggested that the percentage of smudge cells on blood smears from patients with chronic lymphocytic leukemia (CLL) could predict overall survival. However, smudge cells are a cytological artifact influenced by multiple physical factors not related to CLL. To identify simple parameters reflecting CLL cell fragility, we studied CD45 expression in a series of 66 patients with Binet stage A CLL. Decreased CD45 expression was specific for CLL cells when compared to 44 patients with a leukemic phase of B-cell non Hodgkin lymphoma and 42 control B-cells. CD45 expression was markedly decreased for all patients with CLL with high percentages of smudge cells. CLL cells with the lowest CD45 expression were the most sensitive to osmotic shock. Very low levels of CD45 expression were significantly associated with lack of CD38 expression, absence of trisomy 12, and with increased treatment free survival time. Altogether, these results demonstrate that low levels of CD45 expression are specific to CLL cells and reflect cell fragility, suggesting that this is an important intrinsic biological feature that determines disease course.

Nodal and leukemic small B-cell neoplasms

The small B-cell neoplasms represent some of the most frequently encountered lymphoproliferative disorders in routine surgical pathology practice. This report reviews the current diagnostic criteria for classifying small B-cell neoplasms and distinguishing them from newly recognized precursor conditions that do not appear to represent overt lymphomas. Newly available immunohistochemical stains and molecular studies that may assist in the diagnosis and classification of these neoplasms are also discussed.

Chronic lymphocytic leukemia with t(14;18)(q32;q21)

The t(14;18)(q32;q21) is a cytogenetic hallmark of follicular lymphoma and also occurs in approximately 20% of diffuse large B-cell lymphomas of follicle center cell origin. Relatively few cases of chronic lymphocytic leukemia/small lymphocytic lymphoma with t(14;18) have been reported previously. We report the clinicopathologic, cytogenetic, and molecular genetic features of 12 patients with chronic lymphocytic leukemia associated with t(14;18). There were 9 men and 3 women, with a median age of 51 years at diagnosis. To date, 11 patients have required chemotherapy, 6 before coming to our institution. At last follow-up, 5 patients have died of disease. Karyotypic analysis showed that 10 cases had t(14;18) in the stemline and 2 cases in the sideline; t(14;18) was the sole abnormality in the stemline in 2 cases. In 11 cases, other abnormalities were identified in the stemline or sidelines, most commonly trisomy 12 in 6 cases. Trisomy 12 was associated with atypical morphology and immunophenotype. Of 8 cases tested, 7 showed somatically mutated immunoglobulin heavy chain variable region genes. We conclude that the t(14;18) in chronic lymphocytic leukemia is associated with relatively young age at diagnosis, mutated immunoglobulin heavy chain variable region genes, and a clinical course that usually requires chemotherapy. The cytogenetic findings, in particular, t(14;18) in the stemline in 10 cases and as the sole karyotypic abnormality in 2 cases, suggest that t(14;18) is an early pathogenetic event in this small subset of chronic lymphocytic leukemia cases.

Immunophenotyping of chronic B-cell neoplasms: flow cytometry versus immunohistochemistry

Morphological differentiation between benign and malignant lymphoproliferative disorders (LPDs) can be challenging. Immunophenotyping (IPT) by either technique, flow cytometry or immunohistochemistry (IHC), is an important step in solving such difficulty. Thirty-five newly diagnosed patients with chronic B-cell neoplasms (11 chronic lymphocytic leukemia, 22 non Hodgkin lymphoma and 2 hairy cell leukemia) were included in this study with age range from 20 to 70 years. Monoclonal antibodies surface expression using lymphoproliferative disorders panel (CD45, CD19, CD5, CD10, CD11c, CD20, CD22, CD23, CD38, CD79b, FMC7, CD103, CD25, kappa and lambda light chains) by flow cytometry was done on bone marrow samples. CD20, CD5, CD23, Bcl-2, Bcl-6, kappa and lambda light chain immunostaining were performed on fixed bone marrow trephine biopsy specimen. The sensitivity of IHC was 81.8% in chronic lymphocytic leukemia (CLL) and 100% in non Hodgkin lymphoma (NHL) as regards CD20, 100% in both groups as regards CD5, 46% in CLL and 66.7% in NHL as regards CD23, 33.3% in CLL and 50% in NHL as regards kappa chain, 20% in CLL and 33.3% in NHL as regards lambda chain. We found that IHC and flow cytometry are equally effective in diagnosing CLL; however, IHC might be slightly more sensitive than flow cytometry in detecting bone marrow infiltration in NHL and hairy cell leukemia (HCL).

Chronic lymphocytic leukemia and prolymphocytic leukemia with MYC translocations: a subgroup with an aggressive disease course

Translocations involving MYC are rare in chronic lymphocytic leukemia (CLL), and up to now, their prognostic significance remains unclear. We report the characteristics of 21 patients with CLL and nine patients with prolymphocytic leukemia (PLL), diagnosed in multiple centers (n = 13), which showed an MYC translocation demonstrated by fluorescence in situ hybridization. The prevalence was estimated to be <1%. Advanced age and male predominance were observed. Morphological analysis frequently revealed the presence of prolymphocytes. A typical "CLL-immunophenotype" was found in four of nine cases with PLL. Moreover, CD5 and CD23 were frequently expressed in PLL. The latter findings are atypical for PLL and may suggest transformation or progression of an underlying CLL. MYC translocations were frequently observed with concomitant adverse cytogenetic markers, such as del(11q) (n = 8/30) and/or del(17p)/monosomy 17 (n = 7/30). In addition, the presence of unbalanced translocations (n = 24 in 13/30 cases) and complex karyotype (n = 16/30) were frequent in cases with MYC translocations. Altogether, del(17p)/monosomy 17, del(11q), and/or complex karyotype were observed in 22 of 30 patients. Survival outcome was poor: the median time to treatment was only 5 months, and overall survival (OS) from clinical diagnosis and from genetic detection was 71 and 19 months, respectively. In conclusion, CLL/PLL with MYC translocations is a rare entity, which seems to be associated with adverse prognostic features and unfavorable outcome.

A two-gene signature, SKI and SLAMF1, predicts time-to-treatment in previously untreated patients with chronic lymphocytic leukemia

We developed and validated a two-gene signature that predicts prognosis in previously-untreated chronic lymphocytic leukemia (CLL) patients. Using a 65 sample training set, from a cohort of 131 patients, we identified the best clinical models to predict time-to-treatment (TTT) and overall survival (OS). To identify individual genes or combinations in the training set with expression related to prognosis, we cross-validated univariate and multivariate models to predict TTT. We identified four gene sets (5, 6, 12, or 13 genes) to construct multivariate prognostic models. By optimizing each gene set on the training set, we constructed 11 models to predict the time from diagnosis to treatment. Each model also predicted OS and added value to the best clinical models. To determine which contributed the most value when added to clinical variables, we applied the Akaike Information Criterion. Two genes were consistently retained in the models with clinical variables: SKI (v-SKI avian sarcoma viral oncogene homolog) and SLAMF1 (signaling lymphocytic activation molecule family member 1; CD150). We optimized a two-gene model and validated it on an independent test set of 66 samples. This two-gene model predicted prognosis better on the test set than any of the known predictors, including ZAP70 and serum β2-microglobulin.

Revised guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant*

The British Committee for Standards in Haematology first produced guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant in 2000. This revision updates those guidelines and covers the areas of diagnosis, treatment and assessment of response to therapy.

Scoring systems in mantle cell lymphoma: a critical point of view

A proposal for a scoring system in the diagnosis of chronic lymphoproliferative diseases other than CLL has been recently published in Cytometry Part B. The authors apply this score for deciding whether or not FISH evaluation for the detection of IGH/CCND1 rearrangements must be performed to exclude Mantle Cell Lymphoma (MCL). In their validation series, no MCL scored <3. We have applied their system to our cases of MCL and also to a small series of Marginal Zone lymphomas. In our hands, the scoring system as has been published does not discriminate adequately between both entities. We propose using the negativity of a marker, CD11c, instead of the platelet count to improve the results. However, we believe that given the clinical and prognostic implications of the diagnosis of MCL, scoring systems should be greatly ameliorated prior to their generalized use.

Differential and tumor-specific expression of CD160 in B-cell malignancies

CD160 is a human natural killer (NK)-cell-activating receptor that is also expressed on T-cell subsets. In the present study, we examined 811 consecutive cases of B-cell lymphoproliferative disorders (B-LPDs), and demonstrated CD160 expression in 98% (590 of 600) of chronic lymphocytic leukemia (CLL) cases, 100% (32 of 32) of hairy cell leukemia (HCL) cases, 15% (5 of 34) of mantle cell lymphoma (MCL) in the leukemic phase, and 16% (23 of 145) of other B-LPD cases. CD160 transcript and protein were absent in the normal B-cell hierarchy, from stem cells, B-cell precursors, maturing B cells in the germinal center, and circulating B cells, including CD5(+)CD19(+) B1 cells in umbilical cord. CD160 positivity was significantly higher in CLL and HCL in terms of percentage (65.9% and 67.8%, respectively, P < .0001) and median fluorescence intensity (552 and 857, respectively, P < .0001) compared with all other B-LPD cases. Lymph node CLL samples were also CD160(+). Using the disease-specific expression of CD5, CD23, and CD160, a score of 3 characterized CLL (diagnostic odds ratio, 1430); a score of 0 excluded CLL, MCL, and HCL; and the CD23/CD5 ratio differentiated CLL from leukemic CD23(+) MCL. In the B-cell lineage, CD160 is a tumor-specific antigen known to mediate cellular activation signals in CLL, and is a novel target for therapeutic manipulation and monitoring of minimal residual disease.

Autologous stem cell transplantation as a first-line treatment strategy for chronic lymphocytic leukemia: a multicenter, randomized, controlled trial from the SFGM-TC and GFLLC

Long-term responses have been reported after autologous stem cell transplantation (ASCT) for chronic lymphocytic leukemia (CLL). We conducted a prospective, randomized trial of ASCT in previously untreated CLL patients. We enrolled 241 patients < 66 years of age with Binet stage B or C CLL. They received 3 courses of mini-CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone/prednisolone) and then 3 courses of fludarabine. Patients in complete response (CR) were then randomized to ASCT or observation, whereas the other patients were randomized to dexamethasone, high-dose aracytin, cisplatin (DHAP) salvage followed by either ASCT or 3 courses of fludarabine plus cyclophosphamide (FC). The primary end point was event-free survival (EFS). After up-front treatment, 105 patients entered CR and were randomized between ASCT (n = 52) and observation (n = 53); their respective 3-year EFS rates were 79.8% and 35.5%; the adjusted hazard ratio was 0.3 (95% CI: 0.1-0.7; P = .003). Ninety-four patients who did not enter CR were randomized between ASCT (n = 46) and FC (n = 48); their respective 3-year EFS rates were 48.9% and 44.4%, respectively; the adjusted hazard ratio was 1.7 (95% CI: 0.9-3.2; P = .13). No difference in overall survival was found between the 2 response subgroups. In young CLL patients in CR, ASCT consolidation markedly delayed disease progression. No difference was observed between ASCT and FC in patients requiring DHAP salvage.

Chronic lymphocytic leukemia with t(14;19)(q32;q13) is characterized by atypical morphologic and immunophenotypic features and distinctive genetic features

The t(14;19)(q32;q13) involving the IGH@ and BCL3 loci is an infrequent cytogenetic abnormality detected in B-cell malignancies. We describe the clinicopathologic, cytogenetic, and molecular genetic characteristics of 14 cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) with t(14;19)(q32;q13). All patients (10 men and 4 women) had lymphocytosis; 10 had lymphadenopathy. Blood and bone marrow lymphocytes were predominantly small, but cytologically and immunophenotypically atypical. In all cases, t(14;19) was found in the neoplastic stem line; it was the sole abnormality in 4. Ten cases showed additional cytogenetic abnormalities, including trisomy 12 in 9 and complex karyotypes in 7. Fluorescence in situ hybridization demonstrated IGH@/BCL3 fusion gene in all cases. In all cases, the IGHV genes were unmutated, but only 7 expressed ZAP70. Seven cases preferentially used IGHV4-39. Our results indicate that t(14;19)(q32;q13) identifies a subset of CLL/SLL with distinctive clinicopathologic and genetic features. Furthermore, t(14;19) may represent an early, possibly primary, genetic event.

Diagnostic issues in chronic lymphocytic leukaemia (CLL)

The diagnosis of chronic lymphocytic leukaemia (CLL) is based on clinical and laboratory features. Morphology and immunophenotype are the initial diagnostic investigations. In atypical cases, these tests should be complemented with molecular genetics and/or histology to exclude other B-cell disorders of small lymphocytes. Morphologically, CLL can be classified into typical and atypical. Immunophenotyping is the only method that can establish or confirm the diagnosis as CLL lymphocytes have a distinct immunophenotypic signature. A scoring system compounding the results with a set of markers allows firming up the diagnosis. Other immunological markers such as CD38 and ZAP-70 have an important prognostic impact. Fluorescence in situ hybridization (FISH) analysis, chiefly by detecting 17p (TP53 locus) and 11q (ATM) deletions and mutational status of the IgVH gene, also provides prognostic information and may determine the type of therapy. In atypical CLL, histology and/or molecular genetics may be required to exclude other B-cell disorders.

CD5-positive chronic B-cell lymphoproliferative disorders: diagnosis and prognosis of a heterogeneous disease entity

BACKGROUND

The pathology and clinical course of patients with CD5+ chronic B-cell lymphoproliferative disorders, excluding those that present with typical chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) or mantle cell lymphoma, (i.e. CD5+B-CLPD) are poorly defined.

METHODS

We studied patients with CD5+B-CLPD to (1) more completely define the clinical features and pathology of CD5+B-CLPD, (2) compare these features to patients presenting with typical CLL, and (3) test the hypothesis that a subset of patients with CD5+B-CLPD could have a unique B-cell malignancy.

RESULTS

We identified 229 patients with CD5+B-CLPD. A definitive pathological diagnosis was made in all 61 (27%) CD5+B-CLPD patients with nonbone marrow (BM) biopsy specimens considered adequate for a comprehensive pathological examination. The most common diagnosis among these 61 patients was CLL (44%) followed by the leukemic phase of marginal zone lymphoma (34%), lymphoplasmacytic lymphoma (11%), diffuse large B cell lymphoma (8%), and high-grade B cell lymphoma not otherwise specified (2%). In contrast, among 168 patients without a non-BM tissue biopsy specimen, a specific diagnosis could be made on review of all available data in only 24 (14%) with 144 (86%) remaining "unclassified."

CONCLUSIONS

In patients with CD5+B-CLPD, a definitive diagnosis can be made on an adequate non-BM tissue biopsy suggesting that this entity does not include a novel disease. We recommend that all patients with CD5+B-CLPD should have a non-BM tissue biopsy to make a definitive diagnosis prior to initiation of treatment.

Flow cytometry and polymerase chain reaction-based analyses of minimal residual disease in chronic lymphocytic leukemia

New therapeutic strategies developed recently for chronic lymphocytic leukemia (CLL) have led to remarkable treatment response rates and complete hematological remissions. This means highly sensitive and specific techniques are increasingly needed to evaluate minimal residual disease (MRD) in CLL patients. Quantitative MRD levels can be used as prognostic markers, where total MRD eradication is associated with prolonged survival. Nowadays, PCR and flow cytometry techniques used to detect MRD in CLL patients can generate reliable and quantitative results with the highest sensitivity. MRD Flow is based on four-color flow cytometry using specific antibody combinations. For allele specific oligonucleotide real-time quantification (ASO RQ) PCR individual primers are designed to detect a specific immunoglobulin heavy chain (IgH) rearrangement in each patient clone. Five comprehensive studies investigated and compared the sensitivity and specificity of both methods. Groups of patients receiving different therapies were analyzed at different time points to generate quantitative MRD levels and MRD kinetics. All studies confirmed that both methods generate equivalent results with regard to sensitivity and MRD quantification, although each method has advantages and disadvantages in the daily routine of a standard hematological laboratory. Here, we review these investigations and compare their results in the light of modern therapies.

The clinical and biological features of a series of immunophenotypic variant of B-CLL

OBJECTIVES

To describe the clinical and biological features of a series of immunophenotypic variant of B-CLL (v-CLL) characterised by intermediate RMH score, in the absence of t(11;14)(q13;q32) in FISH analysis in comparison with a series of typical CLL.

METHODS

We studied the clinical and biological features of 63 cases of v-CLL and 130 cases of CLL.

RESULTS

We observed significant differences in terms of age <70 yr (P < 0.001), lymphocytosis <20 x 10(9)/L (P < 0.001), lymphocyte doubling time <or=12 months (P = 0.02), high serum beta2-microglobulin levels (P < 0.001) and splenomegaly (P = 0.002); CD38, CD49d, CD1c were more expressed in v-CLL, CD43 in CLL (P < 0.001). IgV(H) mutation and trisomy 12 were more frequent in v-CLL group (P = 0.001; P < 0.001); del13q14 in CLL (P = 0.008). Gene expression profiling of nine v-CLL and 60 CLL indicated that the atypical group presented a specific molecular pattern. After a median follow-up of respectively, 55 (4-196) and 60 months (6-180), 25/42 patients with v-CLL (48%) and 55/93 patients with CLL (59%) were treated. Time to treatment was significantly shorter in IgV(H)-mutated v-CLL vs. mutated CLL (P = 0.006). The median overall survival was worse in v-CLL-mutated cases (P = 0.062).

CONCLUSION

v-CLL should be identified and dealt with separately from classic CLL. In particular, the prognostic markers that are routinely used to characterise classical B-CLL should not be interpreted as having the same meaning.

Biological prognostic markers in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most frequent leukemic disease of adults in the Western world. It is remarkable by an extraordinary heterogeneity of clinical course with overall survival ranging from several months to more than 15 years. Classical staging sytems by Rai and Binet, while readily available and useful for initial assessment of prognosis, are not able to determine individual patient's ongoing clinical course of CLL at the time of diagnosis, especially in early stages. Therefore, newer biological prognostic parameters are currently being clinically evaluated. Mutational status of variable region of immunoglobulin heavy chain genes (IgVH), cytogenetic aberrations, and both intracellular ZAP-70 and surface CD38 expression are recognized as parameters with established prognostic value. Molecules regulating the process of angiogenesis are also considered as promising markers. The purpose of this review is to summarize in detail the specific role of these prognostic factors in chronic lymphocytic leukemia.

Guidelines for an integrated diagnostic approach of chronic lymphoproliferative disorders in the routine laboratory of haematology in Belgium

This paper summarizes the minimal workout of chronic lymphoproliferative disorders in a routine laboratory of haematology as recommended by a team of experienced laboratory supervisors in Belgium, taking into account the specific organisation of healthcare in Belgium, the innovations in the field of molecular analyses and related reimbursement. The starting point was essentially based upon clinical and/or haematological indications and it is emphasized that conclusions should be drawn in close dialogue with the clinician and experts in cytogenetics and histopathology. Reports made in the laboratory should be based upon an integration of cytomorphological, immunophenotypical and molecular data. These guidelines are not intended to be used as universal 'diagnostic pathways', but should be useful in developing local diagnostic pathways. It is well understood that this consensus, being valid anno 2009, may rapidly change with new technologies being introduced and new targets discovered.

Intrinsic and extrinsic factors influencing the clinical course of B-cell chronic lymphocytic leukemia: prognostic markers with pathogenetic relevance

B-cell chronic lymphocytic leukemia (CLL), the most frequent leukemia in the Western world, is characterized by extremely variable clinical courses with survivals ranging from 1 to more than 15 years. The pathogenetic factors playing a key role in defining the biological features of CLL cells, hence eventually influencing the clinical aggressiveness of the disease, are here divided into "intrinsic factors", mainly genomic alterations of CLL cells, and "extrinsic factors", responsible for direct microenvironmental interactions of CLL cells; the latter group includes interactions of CLL cells occurring via the surface B cell receptor (BCR) and dependent to specific molecular features of the BCR itself and/or to the presence of the BCR-associated molecule ZAP-70, or via other non-BCR-dependent interactions, e.g. specific receptor/ligand interactions, such as CD38/CD31 or CD49d/VCAM-1. A putative final model, discussing the pathogenesis and the clinicobiological features of CLL in relationship of these factors, is also provided.

Contribution of Flow Cytometry to the Diagnosis of Malignant and Non Malignant Conditions in Lymph Node Biopsies

In order to assess the contribution of FC to the diagnosis of lymph node disorders we retrospectively compared the pathological and the FC diagnosis made in 118 consecutive lymph node biopsies. Pathological diagnosis included non malignant conditions (n = 43), B-cell Non Hodgkin lymphoma (NHL) (n = 30), T-cell NHL (1 case), carcinoma (n = 18), Hodgkin lymphoma (HL) (n = 15), melanoma (n = 2), chronic myelocytic leukemia (n = 12), miscellaneous non-lymphoid tissues (n = 6) and undetermined conditions (n = 2). Among the 116 assessable samples, FC was in agreement with histology in 102 cases (87.9%; 95%CI = 81-93) which included 38 benign conditions (90%; 95% CI = 77-97%), 29 NHL (96.7%; 95% CI = 83-100), 18 carcinomas (100%; 95% CI = 81-100), and 12 HL (80.0%; 95% CI = 52-96). Discrepancies (14 cases) included 3 HL undiagnosed by FC and 2 granulomatous adenitis with an erroneous FC diagnosis of HL. Finally, a malignant condition was suspected only by FC in 5 cases (1 carcinoma, 2 B-cell and 2 T-cell NHL) and subsequently demonstrated by additional diagnostic procedures. In conclusion, this study confirms that FC performed on fresh lymph node samples is a powerful diagnostic tool in patients with malignant lymphoma. A few cases left undiagnosed by classical pathological analysis can be recognized by FC. Carcinoma is readily identified by FC analysis, while some benign conditions and Hodgkin lymphoma can be misdiagnosed with the use of FC, although the potential of FC to properly recognize HL is improving compared to previously reported studies. FC is a useful adjunct to pathological analysis of lymph node specimens.

Deciphering leukemic B-cell chronic lymphoproliferative disorders

Diagnosis of leukemic B-cell chronic lymphoproliferative disorders (B-CLPD) is a frequent challenge in hematology. In this multicentric study, we prospectively studied 165 new consecutive leukemic patients with B-CLPD selected on the basis of Royal Marsden Hospital scoring system < or =3. The primary aim of the study was to try to decipher the atypical cases and identify homogenous subgroups. Overall, morphological examination contributed to diagnosis in only 20% cases, all of them CD5 negative. Thirty additional cases were CD5 negative suggestive of leukemic marginal zone lymphoma in most cases. The significantly poorer survival of the 26 cyclin D1 positive cases justifies recommending its systematic determination among atypical B-CLPD. CD20 expression segregated clearly two subgroups among CD5 positive cyclin D1 negative B-CLPD. The 17 patients with the CD20 dim profile represent a homogeneous subgroup very close to typical B-cell chronic lymphocytic leukemia (B-CLL) on morphological, phenotypical and cytogenetical criteria. In contrast, the subgroup of 51 patients with a CD20 bright profile is heterogeneous. Their significantly lower p27 expression level suggest the presence of a proliferative component, underlying a more aggressive disease. Further genomic studies are warranted to establish their precise nature. These cases should not be included in the same therapeutic trials as B-CLL.

Chronic lymphocytic leukemia With t(2;14)(p16;q32) involves the BCL11A and IgH genes and is associated with atypical morphologic features and unmutated IgVH genes

The t(2;14)(p16;q32) has been reported previously in only 12 cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The clinicopathologic features have been incompletely described. We describe 6 new cases of CLL/SLL with t(2;14)(p16;q32). All had marrow involvement, 4 had absolute lymphocytosis, 4 had lymphadenopathy, and 3 had hepatosplenomegaly. All showed atypical lymphocyte morphologic features with plasmacytoid differentiation and irregular nuclei; 3 had increased prolymphocytes. Flow cytometry demonstrated typical immunophenotypes in 5 and an atypical immunophenotype in 1. All expressed ZAP70; 5 assessed showed unmutated IgV(H) genes. Karyotyping identified t(2;14)(p16;q32) as the sole abnormality in 1, primary abnormality in 2, and part of a complex karyotype in 3. Fluorescence in situ hybridization analysis revealed BCL11A/IgH rearrangement in all. After chemotherapy, 3 patients died of disease and 3 were alive with disease (median follow-up, 80 months). We conclude that CLL/SLL with t(2;14) (p16;q32) and BCL11A/IgH rearrangement is characterized by atypical morphologic features and unmutated IgV(H) genes.

CD200 expression may help in differential diagnosis between mantle cell lymphoma and B-cell chronic lymphocytic leukemia

Chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL) share many features and their differential diagnosis may be challenging, especially when a leukemic picture alone is present. Monoclonal antibody panels are often useful, with CD23 being the most reliable. However, MCL diagnosis should be confirmed by immunohistochemical cyclin D1 detection, sometimes with equivocal or even negative results. Other cytofluorimetric, cytogenetics or molecular techniques are reliable but not widely available. B-CLL leukemic cells express CD200, a membrane glycoprotein belonging to the immunoglobulin superfamily. We investigated its expression on fresh neoplastic cells of 93 patients with a CD5+ lymphoproliferative disease (79 selected B-CLL and 14 MCL in leukemic phase). Although these data cannot be generalized, all B-CLL samples we examined were positive, with CD200 present on the vast majority of the cells while, in MCL patients, CD200 was expressed by a small minority of CD5+ cells in three subjects and totally absent in the remaining 11. We then examined CD200 expression on paraffin-embedded lymphoid tissues and bone marrow (BM) trephine biopsies from 23 B-CLL and 44 MCL patients. Again, all B-CLL cells were CD200+ both in lymph nodes and in BM while all MCL cells were negative. Adding CD200 in routine panels could be of diagnostic utility in excluding MCL diagnosis.

MYC translocation in chronic lymphocytic leukaemia is associated with increased prolymphocytes and a poor prognosis

Chromosomal translocations that involve MYC, characteristic of Burkitt lymphoma, are rare in chronic lymphocytic leukaemia (CLL). We report the clinical, morphological, immunophenotypic, cytogenetic and molecular genetic features of eight CLL cases with MYC rearrangement. The patients, five men and three women (median age, 71 years) had bone marrow involvement and an absolute peripheral blood lymphocytosis; five had lymphadenopathy; seven had splenomegaly. Prolymphocytes were increased (>/=10%) in all cases. Six cases were classified as CLL with increased prolymphocytes (CLL/PL; prolymphocytes 10-55%), and two were classified as CLL in prolymphocytic transformation (CLL/PT; prolymphocytes >55%). All cases co-expressed CD5, CD19, and CD23; five of eight expressed ZAP-70. Of seven cases tested, four had mutated and three had unmutated IGHV genes. Conventional cytogenetic studies demonstrated t(8;14)(q24.1;q32) in five cases, t(8;22)(q24.1;q11) in two cases, and t(2;8)(p12;q24.1) in one case. Seven cases contained additional chromosomal abnormalities. All patients received combination chemotherapy. Two developed Epstein-Barr virus (EBV)-associated diffuse large B-cell lymphomas (DLBCL) that were clonally unrelated to the CLL. At follow-up, two patients are alive, four died of underlying disease, one died of EBV-associated DLBCL, and one died of an unrelated cancer. In summary, MYC rearrangement, which occurs rarely in CLL patients, is associated with increased prolymphocytes, complex cytogenetic abnormalities, and a poor prognosis.

Predictive value of blood and bone marrow flow cytometry in B-cell lymphoma classification: comparative analysis of flow cytometry and tissue biopsy in 252 patients

OBJECTIVE

To study the effectiveness of peripheral blood (PB) and bone marrow flow cytometric immunophenotyping (FCIP) in predicting the histologic B-cell lymphoma type.

PATIENTS AND METHODS

We studied the FCIP results and tissue histopathology from 252 patients with B-cell lymphoma seen at Mayo Clinic's site in Rochester, MN, between January 1, 1997, and January 1, 2004, who had positive results on PB, bone marrow, or body fluid FCIP and a corresponding diagnostic tissue biopsy specimen.

RESULTS

Most of the B-cell lymphomas studied were low grade, with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma being most common. Flow cytometric immunophenotyping histogram analysis was more informative than tabulated percentage antigen positivity; surface immunoglobulin and CD20 staining intensity, CD5 and CD23 positivity, CD10 positivity, and the coexpression of CD11c/CD22 and CD103 were the most pertinent markers. Using these FCIP parameters and strict immunophenotypic definitions for CLL, mantle cell lymphoma (MCL), and hairy cell leukemia, we obtained greater than 95% specificity for each diagnosis. However, we encountered the following exceptions to standard paradigms of B-cell lymphoma-associated FCIP: (1) CD5 expression by disorders distinct from CLL and MCL, (2) lack of uniform CD5 positivity in some CLL and MCL cases, (3) absence of CD10 in approximately 50% of follicular lymphomas, and (4) expression of CD103 by occasional marginal zone lymphomas.

CONCLUSION

Stringent interpretation of PB and bone marrow FCIP results enables identification of certain B-cell lymphoma types. However, the observed exceptions to accepted immunophenotypic paradigms highlight the occasional phenotypic overlap among diseases and emphasize that a systematic approach to FCIP interpretations is key to providing clinically useful diagnostic information.

Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines

Standardized criteria for diagnosis and response assessment are needed to interpret and compare clinical trials and for approval of new therapeutic agents by regulatory agencies. Therefore, a National Cancer Institute-sponsored Working Group (NCI-WG) on chronic lymphocytic leukemia (CLL) published guidelines for the design and conduct of clinical trials for patients with CLL in 1988, which were updated in 1996. During the past decade, considerable progress has been achieved in defining new prognostic markers, diagnostic parameters, and treatment options. This prompted the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) to provide updated recommendations for the management of CLL in clinical trials and general practice.

CD38 expression in chronic lymphocytic leukemia is regulated by the tumor microenvironment

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease with a highly variable outcome. The prognosis of patients with CLL may be predicted using a number of biomarkers, including the level of CD38 expression at the leukemic cell surface. This study investigates the hypothesis that CD38 expression by CLL cells reflects interactions with nonmalignant cells within pseudofollicles in secondary lymphoid tissue where tumor cell proliferation is thought to occur. CD38 expression is higher in tissues that contain pseudofollicles compared with those that do not. In addition, we show that CD38 expression in CLL is dynamic, changes in response to contact with activated CD4(+) T cells, and identifies cells that are primed to proliferate. Finally, we demonstrate close contact between activated CD4(+) T cells and proliferating tumor in primary patient tissue. Proliferating tumor cells in lymph nodes express CD38, which is in turn associated with an increased number of CD31(+) vascular endothelial cells. Although the factors resulting in colocalization of tumor, T cells, and endothelium remain unclear, the existence of these cellular clusters may provide an explanation for the association between CD38 expression and adverse outcome in CLL and suggests novel therapeutic targets.

Quantitative flow cytometry of ZAP-70 levels in chronic lymphocytic leukemia using molecules of equivalent soluble fluorochrome

BACKGROUND

ZAP-70 has emerged as a potential pivotal prognostic marker for patients with chronic lymphocytic leukemia (CLL), which could replace immunoglobulin heavy chain mutation status. Although several flow cytometry assays have been described for assessing ZAP-70 in CLL, certain technical and scientific issues remain unsolved, which have prevented results of this crucial test from being reported, even in the best routine flow cytometry laboratories. In this report, we aimed to solve some of these issues by providing a computerized quantitative flow cytometric assay for ZAP-70 within the entire CLL population, which would be easy to perform and enable standardization between laboratories.

METHODS

Intracellular ZAP-70 levels in CLL and normal B cells were assessed by molecules of equivalent soluble fluorochrome (MESF), employing Quantum FITC MESF calibration beads to establish a standard curve relating channel value to fluorescence intensity in MESF units and the QuickCal v. 2.2 program (www.bangslabs.com) and clinical relevance of the data was determined.

RESULTS

The average ZAP-70 expression value in the CD19(+)/CD5(+) cells from 35 CLL patients was 103,701 MESF when compared with 12,621 MESF in B cells from 20 normal blood samples. "Low" and "high" ZAP-70 CLL subgroups were defined. Patients with "high ZAP-70 MESF" CLL had a shorter time to disease progression (P = 0.0005) and a more advanced clinical stage (P = 0.0018) when compared with patients in the "low ZAP-70 MESF" CLL subgroup.

CONCLUSIONS

This quantitative analysis method can be employed to obtain a more specific and highly accurate assessment of ZAP-70 levels in CLL cells. The method can easily be standardized, in any routine flow laboratory, thereby improving reproducibility and reliability of ZAP-70 analysis.

Leptomeningeal disease in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common lymphoproliferative disorder in the western hemisphere, with an annual incidence of 3:100000. Commonly patients are asymptomatic but not rarely disease progression occurs in the setting of lymphadenopathy and extensive leukemic burden. Leptomeningeal involvement in patients with CLL is infrequent, with presenting symptoms of headache (23%), acute or chronic changes in mental status (28%), cranial nerve abnormalities (54%) including optic neuropathy (28%), weakness of lower extremities (23%) and cerebellar signs (18%). In this report, we discuss a CLL patient with leptomeningeal involvement, who presented with neurological symptoms as the first clinical sign, and a diagnosis of leptomeningeal was made based on CSF cytology and flow cytometry. Treatment consisted of radiation therapy and intrathecal chemotherapy with arabinoside-cytosine and systemic chemotherapy. On the basis of this patient-report together with 37 other previously reported cases, the clinical characteristics together with treatment options and outcome of leptomeningeal involvement in CLL are reviewed. Our case together with data from the literature indicate that a timely diagnosis and intensive treatment of leptomeningeal disease of CLL may lead to longstanding and complete resolution of neurological symptoms.

Comprehensive genetic characterization of CLL: a study on 506 cases analysed with chromosome banding analysis, interphase FISH, IgVH status and immunophenotyping

In CLL data from chromosome banding analysis (CBA) have been scarce due to the low proliferative activity of CLL cells in vitro. We improved the cultivation technique using an immunostimulatory CpG-oligonucleotide DSP30 and IL-2. A total of 506 CLL samples were analysed with CBA and interphase FISH using probes for the detection of trisomy 12, IgH rearrangements and deletions of 6q21, 11q22.3 (ATM), 13q14 (D13S25 and D13S319) and 17p13 (TP53). A total of 500 of 506 (98.8%) cases were successfully stimulated for metaphase generation and are subject to this study. Aberrations were detected in 415 of 500 (83.0%) cases by CBA and in 392 of 500 (78.4%) cases by FISH. CBA detected 832 abnormalities and FISH only 502. Therefore, CBA offers important information in addition to FISH. (1) CLL is characterized mainly by genomic imbalances and reciprocal translocations are rare. (2) A subgroup with complex aberrant karyotype (16.4%) is identified which is associated with an unmutated IgV(H) status and CD38 expression (P=0.034 and 0.02, respectively). (3) Additional abnormalities are detectable providing new biological insights into different CLL subclasses revealing a much more heterogeneous pattern of cytogenetic abnormalities as assumed so far based on FISH data only. Therefore, prospective clinical trials should evaluate the prognostic impact of newly available CBA data.

Differential diagnosis in chronic lymphocytic leukaemia

The diagnosis of chronic lymphocytic leukaemia (CLL) is based on clinical and laboratory features. Morphology and immunophenotype are the key initial diagnostic tests. In cases with atypical features, these investigations should be complemented with cytogenetics and/or histology to confirm the diagnosis and to exclude other B-cell disorders. Morphologically, CLL can be classified into typical and atypical forms. Cell-marker studies provide a robust foundation to establish the diagnosis as the lymphocytes have a distinct immunophenotypic signature. Although no single antigen is exclusively expressed in CLL cells, when several markers are compounded into a scoring system the results allow firming up of the diagnosis. Other immunological markers, such as CD38 or ZAP-70, have an important prognostic impact. Fluorescence in-situ hybridization (FISH) analysis also provides prognostic information, chiefly by detecting 17 (p53 locus) and 11q deletion, and may determine the type of therapy.

The normal counterpart to the chronic lymphocytic leukemia B cell

Chronic lymphocytic leukemia (CLL) is characterized by the monoclonal expansion of small mature-looking B cells that accumulate in the blood, marrow, and lymphoid organs, and have a remarkable phenotypic homogeneity. By definition, CLL cells co-express CD5 and CD23 with faint to undetectable amounts of monoclonal surface immunoglobulins (sIg). The concept of phenotypic homogeneity has been reinforced by gene expression profiling data, which suggest that the pathogenesis of CLL has to be associated with a fairly common mechanism of transformation. In recent years the biology of CLL has been enriched by an unprecedented flurry of new observations that are leading to a better understanding of the natural history of the disease. Still CLL cells have so far defied any attempt to satisfactorily answer the simple time-honored question of what their cell of origin is. It is the purpose of this review to discuss the features a cell must possess to be considered with reasonable approximation the normal counterpart of a CLL B cell.

Revision of the guidelines for diagnosis and therapy of chronic lymphocytic leukemia (CLL)

During the past 10 years, significant progress has been achieved in defining new prognostic markers, diagnostic parameters, and treatment options in chronic lymphocytic leukemia (CLL). These developments have led to revision of the National Cancer Institute-sponsored Working Group (NCI-WG) guidelines on CLL established in 1988 and 1996. The update of these guidelines will clarify the role of new prognostic markers in CLL, improve the definitions of response and refractory disease, and add information on the prevention and management of infectious and autoimmune complications.