Expression of adhesion molecules in 113 patients with B-cell chronic lymphocytic leukemia: relationship with clinico-prognostic features

The Role of the Microenvironment and Cell Adhesion Molecules in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy whose progression largely depends on the lymph node and bone marrow microenvironment. Indeed, CLL cells actively proliferate in specific regions of these anatomical compartments, known as proliferation centers, while being quiescent in the blood stream. Hence, CLL cell adhesion and migration into these protective niches are critical for CLL pathophysiology. CLL cells are lodged in their microenvironment through a series of molecular interactions that are mediated by cellular adhesion molecules and their counter receptors. The importance of these adhesion molecules in the clinic is demonstrated by the correlation between the expression levels of some of them, in particular CD49d, and the prognostic likelihood. Furthermore, novel therapeutic agents, such as ibrutinib, impair the functions of these adhesion molecules, leading to an egress of CLL cells from the lymph nodes and bone marrow into the circulation together with an inhibition of homing into these survival niches, thereby preventing disease progression. Several adhesion molecules have been shown to participate in CLL adhesion and migration. Their importance also stems from the observation that they are involved in promoting, directly or indirectly, survival signals that sustain CLL proliferation and limit the efficacy of standard and novel chemotherapeutic drugs, a process known as cell adhesion-mediated drug resistance. In this respect, many studies have elucidated the molecular mechanisms underlying cell adhesion-mediated drug resistance, which have highlighted different signaling pathways that may represent potential therapeutic targets. Here, we review the role of the microenvironment and the adhesion molecules that have been shown to be important in CLL and their impact on transendothelial migration and cell-mediated drug resistance. We also discuss how novel therapeutic compounds modulate the function of this important class of molecules.

Implementation of International Prognostic Index with flow cytometry immunophenotyping for better risk stratification of chronic lymphocytic leukemia

BACKGROUND

Current chronic lymphocytic leukemia (CLL) International Prognostic Index (IPI) stratifies patients based on clinical, molecular, and biochemical features; however, B-cell markers also influence CLL outcomes. Here, prognostic roles of CD11c, CD38, and CD49d were first evaluated, and then an immunophenotypic score was combined with CLL-IPI for risk stratification of CLL patients.

METHODS

A total of 171 CLL subjects were included, and surface marker expression was assessed by flow cytometry. Levels ≥30% were chosen as cut-off of positivity to a marker; then values of 1 (for CD11c and CD38) or 3 (for CD49d) were assigned and scores determined for each patient's clone immunophenotype.

RESULTS

CD49d positivity was significantly associated with simultaneous expression of CD11c and/or CD38, unmutated IGHV status, and higher β2-microglobulin levels compared to those with CD49d negativity. Moreover, CD49d⁺ patients experienced a shorter progression-free survival and time to treatment. When the immunophenotypic score was combined with CLL-IPI, patients with high-risk immunophenotype had a significantly lower time-to-treatment regardless CLL-IPI.

CONCLUSIONS

Our results suggested clinical utility of an integrated prognostic score for better risk stratification of CLL patients. These results require further validation in prospective larger studies.

BCR activated CLL B cells use both CR3 (CD11b/CD18) and CR4 (CD11c/CD18) for adhesion while CR4 has a dominant role in migration towards SDF-1

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in the western world. In previous studies, various proportion of patients was found to carry CD11b+ or CD11c+ B cells whose presence was an unfavourable prognostic factor. The exact mechanism however, how these receptors contribute to the pathogenesis of CLL has not been revealed so far. Here we analysed the role of CD11b and CD11c on B cells of CLL patients in the adhesion to fibrinogen and in the migration towards stromal cell derived factor-1 (SDF-1) and studied the role of CR4 in the adherence of the CD11c+ B cell line BJAB. We observed that both CR3 and CR4 mediate adhesion of the malignant B cells. Moreover, we found, that CR4 was strongly involved in the migration of the leukemic cells towards the chemoattractant SDF-1. Our data suggest that CR3 and CR4 are not only passive markers on CLL B cells, but they might contribute to the progression of the disease. Since the role of SDF-1 is prominent in the migration of CLL cells into the bone marrow where their survival is supported, our findings help to understand how the presence of CD11c on leukemic B cells can worsen the prognosis of chronic lymphocytic leukaemia.

New aspects in the regulation of human B cell functions by complement receptors CR1, CR2, CR3 and CR4

The involvement of complement in the regulation of antibody responses has been known for long. By now several additional B cell functions - including cytokine production and antigen presentation - have also been shown to be regulated by complement proteins. Most of these important activities are mediated by receptors interacting with activation fragments of the central component of the complement system C3, such as C3b, iC3b and C3d, which are covalently attached to antigens and immune complexes. This review summarizes the role of complement receptors interacting with these ligands, namely CR1 (CD35), CR2 (CD21), CR3 (CD11b/CD18) and CR4 (CD11c/CD18) expressed by B cells in health and disease. Although we focus on human B lymphocytes, we also aim to call the attention to important differences between human and mouse systems.

CD markers variations in chronic lymphocytic leukemia: New insights into prognosis

Chronic lymphocytic leukemia (CLL) is one of the most commonly occurring adult leukemias that is associated with clonal accumulation of mature apoptosis-resistant B-cells in bone marrow, peripheral blood, and specific tissues. Different pathogenesis factors can contribute to the aggression of the clinical course in this disease. Cytogenetic abnormalities and surface biomarkers of neoplastic CLL cells can be effective in the outcome of CLL, and the examination of changing CD markers expressions in the progression of CLL can be related to the prognosis of this disease. Changing expression levels of CD markers on lymphocytes and other cells in CLL patients can play a role in the aggressive clinical outcomes such as organomegaly, immunodeficiency, and advanced disease stages through their interaction with CLL microenvironment. Given the involvement of CD markers in the pathogenesis of CLL, it can be stated that recognizing the expression changes of CD markers in the cells involved in CLL can be a proper approach to evaluate prognosis among these patients.

Functional studies of chronic lymphocytic leukemia B cells expressing β2-integrin type complement receptors CR3 and CR4

The expression and role of CR3 (CD11b/CD18) and CR4 (CD11c/CD18) in B cells are not yet explored in contrast to myeloid cells, where these β₂-integrin type receptors are known to participate in various cellular functions, including phagocytosis, adherence and migration. Here we aimed to reveal the expression and role of CR3 and CR4 in human B cells. In B cells of healthy donors CR3 and CR4 are scarcely expressed. However, two patients with chronic lymphocytic leukemia (CLL) characterized by a peculiar immune-phenotype containing both CD5-positive and CD5-negative B cell populations made possible to study these molecules in distinct B cell subsets. We found that CD11b and CD11c were expressed on both CD5-positive and CD5-negative B cells, albeit to different extents. Our data suggest that these receptors are involved in spreading, since this activity of CpG-activated B cells on fibrinogen could be partially blocked by monoclonal antibodies specific for CD11b or CD11c. CpG-stimulation lead to proliferation of both CD5-positive and CD5-negative B cells of the patients with a less pronounced effect on the CD5-positive cells. In contrast to normal B cells, CLL B cells of both patients reacted to CpG-stimulation with robust IL-10 production. The concomitant, suboptimal stimulus via the BCR and TLR9 exerted either a synergistic enhancing effect or resulted in inhibition of proliferation and IL-10 production of patients' B cells. Our data obtained studying B cells of leukemic patients point to the role of CR3 and probably CR4 in the interaction of tumor cells with the microenvironment and suggest the involvement of IL-10 producing B cells in the pathologic process.

Cytogenetic and flow cytometry evaluation of Richter syndrome reveals MYC, CDKN2A, IGH alterations with loss of CD52, CD62L and increase of CD71 antigen expression as the most frequent recurrent abnormalities

OBJECTIVES

Richter syndrome (RS) is a transformation of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) into high-grade lymphoma. There are only limited data on flow cytometry (FCM) and cytogenetics in RS.

METHODS

In this study, FCM, classic cytogenetics (CC), and fluorescence in situ hybridization (FISH) were performed in eight RS cases.

RESULTS

Most cases of RS were characterized by a loss/decrease of CD52 and CD62L and increased CD71 expression. CC identified complex karyotypes, with losses of 9/9p and 17/17p as the most frequent in four of seven cases. Seven RS cases demonstrated MYC abnormalities. Disruptions of CDKN2A and IGH were identified in five of seven and four of seven RS cases, respectively.

CONCLUSIONS

Newly diagnosed RS is an oncologic emergency, and a quick diagnostic decision is crucial in clinical practice. Therefore, in patients with CLL/SLL and rapidly enlarging asymmetric lymphadenopathy and/or extranodal tumors, we strongly advise FCM of fine-needle aspiration biopsy (FNAB) material, including CD62L, CD52, and CD71 analysis as well as assessment of karyotype and at least MYC abnormalities by FISH of the same FNAB material. Loss of CD52 expression in RS most likely predicts resistance to alemtuzumab therapy, which is frequently used in CLL.

Small lymphocytic lymphoma and chronic lymphocytic leukemia: are they the same disease?

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world, characterized by peripheral blood B-cell lymphocytosis as well as lymphadenopathy, organomegaly, cytopenias, and systemic symptoms. Chronic lymphocytic leukemia cells have a distinctive immunophenotype, and the disease has a characteristic pattern of histological infiltration in the lymph node and bone marrow. The clinical course of CLL is heterogeneous, with some patients presenting with very indolent disease and other patients having a more aggressive malignancy. It is known that genetic abnormalities underlie this difference in clinical presentation. Some patients may present solely with lymphadenopathy, organomegaly, and presence of infiltrating monoclonal B cells with the same immunophenotype as CLL cells, but lacking peripheral blood lymphocytosis. This disease is called small lymphocytic lymphoma (SLL) and has been considered for almost 2 decades to be the tissue equivalent of CLL. Both CLL and SLL are currently considered different manifestations of the same entity by the fourth edition of the World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues. It is suspected that differential expression of chemokine receptors (e.g., reduced expression of R1 and CCR3 in SLL cells), integrins (e.g., CLL cells have lower expression of integrin αLβ2), and genetic abnormalities (a higher incidence of trisomy 12 and lower incidence of del(13q) is found in SLL) may explain some of the clinical differences between these 2 disorders. However, there is still a lack of knowledge on the precise biological basis underlying the different clinical presentations of CLL and SLL. It is expected that future studies will shed light on the pathophysiology of both disorders.

The role of CD11c expression in the diagnosis of mantle cell lymphoma

Flow cytometric immunophenotyping (FCI) aids in the differentiation of chronic lymphocytic leukemia (CLL) from mantle cell lymphoma (MCL); however, overlapping phenotypes may occur. CD11c expression has been reported in up to 90% of CLL cases but has rarely been reported in MCL. Whether CD11c can be used to exclude MCL has not been directly addressed. FCI reports were reviewed for 90 MCL cases (44 patients) and 355 CLL/small lymphocytic lymphoma (SLL) cases (158 patients). MCL cases were confirmed by cyclin D1 immunoreactivity and/or t(11;14) detection by karyotyping or fluorescence in situ hybridization. Cases with typical MCL immunophenotypes did not express CD11c. The 2 MCL cases displaying dim CD11c positivity (2 of 44 patients) expressed other markers not typical of MCL. CD11c was detected in 96 (27.0%) of 355 cases of CLL/SLL representing 53 of 158 patients. CD11c expression is rare in MCL and may aid in differentiation of CD5+ B-cell neoplasms, particularly when small samples limit further ancillary testing.

Bcl-2 regulatory pathway is functional in chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is characterized by accumulation of clonal, malignant CD5(+), CD23(+) B cells. In vivo, these cells have an antiapoptotic phenotype (high levels of Bcl-2 and low levels of proapoptotic Bcl-2 family proteins, such as Bax). Abnormal B cells accumulate due to altered apoptosis regulation rather than to increased proliferation. However, it is unclear whether there are inherent Bcl-2 apoptotic pathway defects. With in vitro culture, these B cells rapidly apoptosis.

METHODS

To investigate apoptosis regulation, Bcl-2, Bax, mitochondrial membrane potential, annexin V, and caspase activation were simultaneous monitored in individual cells during in vitro apoptosis.

RESULTS

With in vitro culture, 30% to 50% of B cells were apoptotic at 24 h compared with fewer than 10% of T cells. Apoptotic B cells showed dramatic Bax upregulation and slight Bcl-2 decreases accompanied by decreased mitochondrial membrane potential and increased activated caspase-3 protein levels. Caspase-3 and caspase-9 activities were increased 18- to 51-fold and 6- to 11-fold, respectively, after 24 h of culture. Caspase-8 showed limited or no activation (less than fourfold).

CONCLUSIONS

These data show that in vitro apoptosis of CLL B cells occurs through a well-characterized Bcl-2 regulatory pathway consistent with that pathway being functional. Further, these cells' antiapoptotic phenotype is dependent on the in vivo environment, potentially involving paracrine/autocrine interactions.

Leukotriene B4 plays a pivotal role in CD40-dependent activation of chronic B lymphocytic leukemia cells

Biosynthesis of leukotrienes (LTs) occurs in human myeloid cells and B lymphocytes. However, the function of leukotrienes in B lymphocytes is unclear. Here, we report that B-cell chronic lymphocytic leukemia (B-CLL) cells produce leukotriene B4, and that specific leukotriene biosynthesis inhibitors counteracted CD40-dependent activation of B-CLL cells. Studies on the expression of the high-affinity receptor for LTB4 (BLT1) by flow cytometry analysis showed that the receptor was expressed, to a varying degree, in all investigated B-CLL clones. At a concentration of 100 nM, the drugs BWA4C (a specific 5-lipoxygenase inhibitor) and MK-886 (a specific 5-lipoxygenase activating protein inhibitor) markedly inhibited CD40-induced DNA synthesis (45% and 38%, respectively) and CD40-induced expression of CD23, CD54, and CD150. Addition of exogenous LTB4 (150 nM) almost completely reversed the effect of the inhibitors on DNA synthesis and antigen expression. Taken together, the results of the present study suggest that leukotriene biosynthesis inhibitors may have a therapeutic role in B-CLL.

Elevated levels of soluble CD44 are associated with advanced disease and in vitro proliferation of neoplastic lymphocytes in B-cell chronic lymphocytic leukaemia

PURPOSE

Increased expression of the adhesion molecule CD44 has been associated with an unfavourable clinical outcome in lymphomas. We evaluated the prognostic value of soluble CD44 in B-cell chronic lymphocytic leukaemia (B-CLL) and analysed the source and regulation of CD44 secretion in B-CLL clones in vitro.

PATIENTS AND METHODS

Levels of soluble CD44 standard (sCD44s) and of the soluble variant isoform CD44v6 (sCD44v6) were analysed by enzyme linked immuno sorbent assay. Highly purified B-CLL cells (98% CD19 + CD3 - cells) were stimulated in vitro by different combinations of thioredoxin (Trx), Staphylococcus aureus Cowan strain 1 (SAC), IL-2, IL-4, IL-10, 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and by anti-CD40 mAbs presented on irradiated CD32L cells.

RESULTS

Serum levels of sCD44s and of sCD44v6 are significantly elevated in B-CLL patients (n = 90) in comparison with normal persons (n = 44) (P < 0.001). Elevated levels of sCD44s and sCD44v6 are associated with an advanced disease as reflected by an extended lymph node involvement (P < 0.02), an advanced Binet (P < 0.03) and Rai stage (P < 0.04) and chemotherapy requirement (P < 0.02). High levels of sCD44s are associated with high leukocyte counts (P < 0.04) and increased sCD44v6 is significantly associated with splenomegaly (P < 0.002). In B-CLL sCD44s as well as sCD44v6 is shed from leukaemia cells as shown by in vitro cultures. Stimulation of B-CLL clones results in a proliferation-associated increased secretion of sCD44s (rho = 0.7; P = 0.0001) and of sCD44v6 (rho = 0.5; P = 0.005). B-CLL clones from advanced stage patients are characterised by an increased capacity for proliferation and CD44 production in comparison with early stage patients.

CONCLUSIONS

Both sCD44s and sCD44v6 represent a reliable prognostic marker in B-CLL and may be involved in the pathogenesis of B-CLL.

Integrin expression and survival in human breast cancer

BACKGROUND

Integrin cell adhesion molecules are fundamental to numerous cellular functions including anchorage, differentiation and proliferation. Reduced expression of certain alpha and beta integrin subunits in primary breast cancer cells has been correlated with increased invasion and metastasis. Conversely, over-expression of the alpha6 subunit has been linked to poorer survival. The objective of this study was to measure the survival of a cohort with breast carcinoma in relation to integrin expression and to evaluate their potential as prognostic indicators.

METHOD

Integrin expression on samples from 99 consecutive patients with breast cancer was assayed using monoclonal antibodies to the subunits alpha(1,2,3,6,V) and beta(1,3,4,5). This cohort has now been followed prospectively for almost five years allowing for early assessment of survival in relation to integrin expression.

RESULTS

Whilst analysis of the data confirmed the relation of survival to proven predictors of tumour grade, tumour size and vascular invasion, statistical significance was not demonstrated with regard to both lymph node status and all integrin subunits studied.

CONCLUSION

Previous research correlating certain integrin subunits with survival has not been confirmed in this study. Despite proven molecular importance in tumour cell adhesion, invasion and metastasis, integrin expression would appear not to translate clinically as independent indicators of prognosis, at least in the short-term.

B-chronic lymphocytic leukemia: practical aspects

B-CLL is the most common adult leukemia in the Western world. It is a neoplasia of mature looking B-monoclonal lymphocytes co-expressing the CD5 antigen (involving the blood, the bone marrow, the lymph nodes and related organs). Much new information about the nature of the neoplastic cells, including chromosomal and molecular changes as well as mechanisms participating in the survival of the leukemic clone have been published recently, in an attempt to elucidate the biology of the disease and identify prognostic subgroups. For the time being, clinical stage based on Rai and Binet staging systems remains the strongest predictor of prognosis and patients' survival, and therefore it affects treatment decisions. In the early stages treatment may be delayed until progression. When treatment is necessary according to well-established criteria, there are nowadays many different options. Chlorambucil has been the standard regimen for many years. During the last decade novel modalities have been tried with the emphasis on fludarabine and 2-chlorodeoxyadenosine and their combinations with other drugs. Such an approach offers greater probability of a durable complete remission but no effect on overall survival has been clearly proven so far. Other modalities, included in the therapeutic armamentarium, are monoclonal antibodies, stem cell transplantation (autologous or allogeneic) and new experimental drugs. Supportive care is an important part of patient management and it involves restoring hypogammaglobulinemia and disease-related anemia by polyvalent immunoglobulin administration and erythropoietin respectively.

Cleaved lymphocytes in chronic lymphocytic leukemia: a detailed retrospective analysis of diagnostic features

Through a global analysis of diagnostic features, the aim was to profile CLL patients with circulating cleaved lymphocytes at diagnosis, a controversial prognostic factor. Although some of them could have been considered today as having Non-Hodgkin's lymphoma, all 106 patients of our retrospective series have had CLL treatments. Slide review distinguished seven lymphocyte morphotypes. With minimal a priori assumptions, excluding in particular clinical staging systems, forty-five diagnostic features were analyzed in 37 patients. CORICO (Correlations Iconography), a purely geometric method, deciphered the multidimensional structure of the raw data. Probabilistic monoparametric tests were made on the 106 patients. In ten patients (Binet stages: 3A, 6B, 1C), at least 8% of the lymphocytes were cleaved. Unrelated to the prolymphocytes, this morphotype had neither links with the CD5+CD23+ (9/10 vs 80/86), FMC7+ (5/10 vs 22/62), CD38 (1/7 vs 7/64) markers nor with any major CLL laboratory values; only three links characterized it: no cases of mixed marrow infiltrate (nodular: 1, interstitial: 6, diffuse: 3; ns), a lower percentage of eosinophils (ns), and predominance of CD11c (7/10 vs 20/66, p < 0.02). In conclusion, in contrast to the PLL morphotype, or to the lactic dehydrogenase (LDH) activity, which was a strong prognostic factor in this series, an independent detrimental value of the cleaved morphotype has not yet been found. Our study shows that free of modeling constraints, this method makes possible a rapid and objective insight into variable interrelations. If further explored in a prospective study, this approach may contribute to the understanding of discrepancies in the literature.

Cell surface expression of CD25, CD54, and CD95 on B- and T-cells in chronic lymphocytic leukaemia in relation to trisomy 12, atypical morphology and clinical course

BACKGROUND

Surface antigen expression can be used to define subgroups of patients with different clinical courses in chronic lymphocytic leukaemia of the B-cell type (CLL). PURPOSE-METHODS: To study the clinical significance of functional markers linked to proliferation (CD25), adhesion (CD54), and apoptosis (CD95) on B- and T-cells in 68 patients with CLL using dual colour flow cytometry (FCM).

RESULTS

The mean proportion of CD19+ B-cells expressing CD25 was significantly higher in CLL patients compared to controls (P=0.02), while CD54+ and CD95+ B-cells did not differ significantly. In CLL with atypical morphology and in patients with trisomy 12, the mean percentage of CD25+ B-cells was lower than in typical CLL (P<0.02) and in patients with disomic tumor cells (P<0.03). Patients with 30% of CD25+ B-cells had a shorter median time to treatment than CD25-negative cases (P=0.01). A low CD54 expression was associated with a prolonged median time to treatment (P=0.004), low WBC counts (P<0.05), and low S-LDH (P=0.03). A high CD95 expression was correlated with elevated S-LDH (P=0.02) and a finding of lymphadenopathy (P=0.02). In individual patients there was a strong correlation between B- and T-cell expression of CD25 (P<0.0001), CD54 (P=0.0002), and CD95 (P=0.0002), respectively.

CONCLUSIONS

CD25 and CD54 expression on CD19+ cells seems to give prognostic information. The strong correlation between the expression of CD25, CD54 and CD95 on B-and T-cells suggests that the expression of these antigens is not an inherent characteristic of the malignant B-cell clone.

Atypical lymphocytic leukemia and mantle cell lymphoma immunologically very close: flow cytometric distinction by the use of CD20 and CD54 expression

Integration of morphological and immunophenotypic data is critical in achieving diagnosis accuracy and minimising interobserver interpretative discrepancies. The aim of this work was to compare the immunophenotype and the morphology of chronic lymphocytic leukaemia and mantle cell lymphoma, to help in the differential diagnosis of CD5 positive monoclonal B cells. Frozen/thawed samples from 91 patients were analysed retrospectively. Fresh samples from 17 mixed/atypical CLL and 13 MCL were tested to corroborate the results. Markers were analysed as percentage (%) of positive B lymphocyte subpopulation, and in terms of median fluorescence intensity (MFI). Matutes's CLL score clearly allowed distinguishing between classical CLL on the one hand, and atypical CLL and MCL on the other hand. The percentage of CD54-positive cells and the median fluorescence intensity of CD20 and CD54 were the only parameters which were significantly higher in MCL than in atypical CLL (P < 0.05), allowing an immunological distinction between these two entities. Nevertheless, due to a quenching problem when using CD20 and CD54 together, and because CD18 showed a statistically different expression between classical and atypical CLL, the combination of CD18/CD54 has been preferred and showed a different pattern in the three entities. Immunophenotyping could be helpful in the differential diagnosis of CD5-positive B cell chronic lymphoproliferative disorders with atypical features that do not fit exactly into any of the morphologic proposed groups.

CDNA microarray gene expression analysis of B-cell chronic lymphocytic leukemia proposes potential new prognostic markers involved in lymphocyte trafficking

Human cancer is characterized by complex molecular perturbations leading to variable clinical behavior, often even in single-disease entities. We performed a feasibility study systematically comparing large-scale gene expression profiles with clinical features in human B-cell chronic lymphocytic leukemia (B-CLL). cDNA microarrays were employed to determine the expression levels of 1,024 selected genes in 54 peripheral blood lymphocyte samples obtained from patients with B-CLL. Statistical analyses were applied to correlate the expression profiles with a number of clinical parameters including patient survival and disease staging. We were able to identify genes whose expression levels significantly correlated with patient survival and/or with clinical staging. Most of these genes code either for cell adhesion molecules (L-selectin, integrin-beta2) or for factors inducing cell adhesion molecules (IL-1beta, IL-8, EGR1), suggesting that prognosis of this disease may be related to a defect in lymphocyte trafficking. This report demonstrates the feasibility of a systematic integration of large-scale gene expression profiles with clinical data as a general approach for dissecting human diseases.

Morphological and immunophenotypic features of chronic lymphocytic leukemia

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

Expression of LFA-1 identifies different prognostic subgroups in patients with advanced follicle center lymphoma (FCL)

In a retrospective immunohistochemical study based on 27 patients with stage IV follicle center lymphoma (FCL) the expression of CD44standard (CD44s), LFA-1 (CD11a, CD18), VLA-4 (CD49d, CD29) and ICAM-1 (CD54) was analysed on lymphoma cells in bone marrow infiltrates. The results were correlated to clinical data and overall survival. Our data demonstrate that the expression of LFA-1 on lymphoma cells is predictive for the prognosis of patients with advanced FCL. In detail, patients exhibiting weak to moderate expression (+/++) of CD11 and CD18 showed a significantly shorter median survival (51 months and 33 months, respectively) than did those presenting with strong expression ( ) of the LFA-1 adhesion molecule (P = 0.04 and P = 0.0051, respectively). Furthermore, multivariate analysis identified CD18 as a new independent prognostic factor in patients with advanced FCL. Our findings emphasize the relevance of adhesion molecules for the pathology of FCL and give further support for their impact on clinical course and overall survival.

Reduced Expression of Adhesion Molecules and Cell Signaling Receptors by Chronic Lymphocytic Leukemia Cells With 11q Deletion

Deletions in chromosome bands 11q22-q23 were recently shown to be one of the most frequent chromosome aberrations in B-cell chronic lymphocytic leukemia (B-CLL). Patients suffering from B-CLL with 11q deletion are characterized by extensive lymphadenopathy, rapid disease progression, and short survival times. Phenotypic and functional characteristics of B-CLL cells with 11q deletion that may help to explain the pathophysiology of this entity are yet unknown. In the present study, B-CLL cells with (n = 19) and without (n = 19) 11q deletion were analyzed for their expression of functionally relevant cell surface molecules (n = 57). B-CLL cells with 11q deletion carried significantly lower levels of the adhesion molecules CD11a/CD18 (integrin L/β2), CD11c/CD18 (integrin X/β2), CD31 (PECAM-1), CD48, and CD58 (LFA-3). Furthermore, B-CLL cells with 11q deletion expressed less the cell signaling receptors CD45 (leukocyte common antigen [LCA]), CD6, CD35 (complement receptor 1), and CD39. Reduced CD45 levels and low-level expression of CD49d correlated with decreased overall survival. B-CLL cells with or without 11q deletion did not differ in their growth fractions, expression levels of transcription factor NF-κB, or their response to mitogenic stimuli. Decreased levels of functionally relevant adhesion molecules and of cell signaling receptors may contribute to the pathogenesis of the subgroup of B-CLL characterized by 11q22-q23 deletion.

Reduced Expression of Adhesion Molecules and Cell Signaling Receptors by Chronic Lymphocytic Leukemia Cells With 11q Deletion

Deletions in chromosome bands 11q22-q23 were recently shown to be one of the most frequent chromosome aberrations in B-cell chronic lymphocytic leukemia (B-CLL). Patients suffering from B-CLL with 11q deletion are characterized by extensive lymphadenopathy, rapid disease progression, and short survival times. Phenotypic and functional characteristics of B-CLL cells with 11q deletion that may help to explain the pathophysiology of this entity are yet unknown. In the present study, B-CLL cells with (n = 19) and without (n = 19) 11q deletion were analyzed for their expression of functionally relevant cell surface molecules (n = 57). B-CLL cells with 11q deletion carried significantly lower levels of the adhesion molecules CD11a/CD18 (integrin L/β2), CD11c/CD18 (integrin X/β2), CD31 (PECAM-1), CD48, and CD58 (LFA-3). Furthermore, B-CLL cells with 11q deletion expressed less the cell signaling receptors CD45 (leukocyte common antigen [LCA]), CD6, CD35 (complement receptor 1), and CD39. Reduced CD45 levels and low-level expression of CD49d correlated with decreased overall survival. B-CLL cells with or without 11q deletion did not differ in their growth fractions, expression levels of transcription factor NF-κB, or their response to mitogenic stimuli. Decreased levels of functionally relevant adhesion molecules and of cell signaling receptors may contribute to the pathogenesis of the subgroup of B-CLL characterized by 11q22-q23 deletion.

Elevated serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) closely reflect tumour burden in chronic B-lymphocytic leukaemia

The present study is the first to report elevated serum levels of soluble (s)VCAM-1 in B-cell chronic lymphocytic leukaemia (B-CLL). A large cohort of 106 untreated patients was studied. sVCAM-1 was compared to known prognostic serum markers (soluble (s)ICAM-1; lactate dehydrogenase, LDH; sCD23; thymidine kinase, TK; beta2microglobulin, beta2m). The serum levels of sVCAM-1 reflected tumour burden as expressed by Binet/Rai stages more closely than any other marker. sVCAM-1 also reflected the kinetics of the disease as revealed by lymphocyte doubling time. sVCAM-1 was the only one of the studied markers which showed elevated levels in smouldering disease compared to controls. sVCAM-1, sICAM-1 and sCD23 (but not LDH, TK, beta2m) separated smouldering from non-smouldering B-CLL. Only sICAM-1, sCD23 and TK added independent prognostic information for survival to that of stage and lymphocyte doubling time. The expression of both adhesion molecules was examined in lymph node and splenic specimens. VCAM-1 and ICAM-1 were overexpressed by vascular endothelium and stroma, but the intensity of expression correlated poorly with serum levels of the soluble molecules. In conclusion, serum levels of sVCAM-1 correlated with tumour burden and other prognostic markers in B-CLL. VCAM-1 was overexpressed in tumour tissue as was ICAM-1. sVCAM-1 could prove a valuable marker in younger early-stage patients eligible for therapeutic trials.