From normal to clonal B cells: Chronic lymphocytic leukemia (CLL) at the crossroad between neoplasia and autoimmunity

Monoclonal B-cell Lymphocytosis - a review of diagnostic criteria, biology, natural history, and clinical management

Since first described almost two decades ago, there has been significant evolution in our definition and understanding of the biology and implications of monoclonal B-cell lymphocytosis (MBL). This review provides an overview of the definition, classification, biology, and natural history of MBL, mainly focused on the dominant CLL-like phenotype form of MBL. The increasingly recognized implications of MBL with respect to immune dysfunction are discussed, particularly in view of the COVID-19 pandemic, along with management recommendations for MBL in the clinic.

The Role of IgM Antibodies in T Cell Lymphoma Protection in a Novel Model Resembling Anaplastic Large Cell Lymphoma

MRL/lpr mice typically succumb to immune complex-mediated nephritis within the first year of life. However, MRL/lpr mice that only secrete IgM Abs because of activation-induced deaminase deficiency (AID^-/-MRL/lpr mice) experienced a dramatic increase in survival. Further crossing of these mice to those incapable of making secretory IgM (μS mice) generated mice lacking any secreted Abs but with normal B cell receptors. Both strains revealed no kidney pathology, yet Ab-deficient mice still experienced high mortality. In this article, we report Ab-deficient MRL/lpr mice progressed to high-grade T cell lymphoma that can be reversed with injection of autoreactive IgM Abs or following adoptive transfer of IgM-secreting MRL/lpr B cells. Anti-nuclear Abs, particularly anti-dsDNA IgM Abs, exhibited tumor-killing activities against a murine T cell lymphoma cell line. Passive transfers of autoreactive IgM Abs into p53-deficient mice increased survival by delaying onset of T cell lymphoma. The lymphoma originated from a double-negative aberrant T cell population seen in MRL/lpr mice and most closely resembled human anaplastic large cell lymphoma. Combined, these results strongly implicate autoreactive IgM Abs in protection against T cell lymphoma.

Inactivated STAT5 pathway underlies a novel inhibitory role of EBF1 in chronic lymphocytic leukemia

B-cell chronic lymphocytic leukemia (CLL) is a disease caused by gradual accumulation of functionally incompetent lymphocytes. The majority of CLL cases are accompanied by chemoresistance. Early B cell factor 1 (EBF1) is a crucial contributor to B-cell lymphopoiesis. This study is to explore the effect of EBF1 on CLL cell progression and its involvement in regulating the signal transducers and activators of transcription 5 (STAT5) pathway. We conducted a correlation analysis between EBF1 and the clinical characteristics of CLL patients. Subsequently, EBF1 was overexpressed by transfection with EBF1 overexpression plasmid and the STAT5 pathway was also blocked by treatment with SH-4-54 in isolated CD20⁺ B lymphocytes to investigate their roles in the regulation of cellular functions. STAT5, Janus kinase 2 (JAK2) expression and their phosphorylation levels were determined by quantitative PCR and Western blot analyses. The in vivo effects of EBF1 on tumor growth were evaluated using a xenotransplant model. Downregulation of EBF1 was observed in CD20⁺ B lymphocytes of CLL patients. EBF1 overexpression disrupted the activation of STAT5 pathway, as evidenced by decreased expression and phosphorylation levels of STAT5 and JAK2. Furthermore, overexpression of EBF1 repressed viability and cell cycle entry, and increased apoptosis of CD20⁺ B lymphocytes by inhibiting the STAT5 pathway. Finally, EBF1 exerted antitumor effects in nude mice. Overall, our study elucidates the inhibitory role of EBF1 in CLL through inactivation of the STAT5 pathway, which may provide new targets for CLL treatment.

Immune Response Dysfunction in Chronic Lymphocytic Leukemia: Dissecting Molecular Mechanisms and Microenvironmental Conditions

Representing the major cause of morbidity and mortality for chronic lymphocytic leukemia (CLL) patients, immunosuppression is a common feature of the disease. Effectors of the innate and the adaptive immune response show marked dysfunction and skewing towards the generation of a tolerant environment that favors disease expansion. Major deregulations are found in the T lymphocyte compartment, with inhibition of CD8⁺ cytotoxic and CD4⁺ activated effector T cells, replaced by exhausted and more tolerogenic subsets. Likewise, differentiation of monocytes towards a suppressive M2-like phenotype is induced at the expense of pro-inflammatory sub-populations. Thanks to their B-regulatory phenotype, leukemic cells play a central role in driving immunosuppression, progressively inhibiting immune responses. A number of signaling cascades triggered by soluble mediators and cell–cell contacts contribute to immunomodulation in CLL, fostered also by local environmental conditions, such as hypoxia and derived metabolic acidosis. Specifically, molecular pathways modulating T-cell activity in CLL, spanning from the best known cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death 1 (PD-1) to the emerging T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)/CD155 axes, are attracting increasing research interest and therapeutic relevance also in the CLL field. On the other hand, in the microenvironment, the B cell receptor (BCR), which is undoubtedly the master regulator of leukemic cell behavior, plays an important role in orchestrating immune responses, as well. Lastly, local conditions of hypoxia, typical of the lymphoid niche, have major effects both on CLL cells and on non-leukemic immune cells, partly mediated through adenosine signaling, for which novel specific inhibitors are currently under development. In summary, this review will provide an overview of the molecular and microenvironmental mechanisms that modify innate and adaptive immune responses of CLL patients, focusing attention on those that may have therapeutic implications.

Humoral immune responses toward tumor-derived antigens in previously untreated patients with chronic lymphocytic leukemia

In chronic lymphocytic leukemia (CLL) the occurrence and the impact of antibody responses toward tumor-derived antigens are largely unexplored. Our serological proteomic data show that antibodies toward 47 identified antigens are detectable in 29 out of 35 patients (83%) with untreated CLL. The glycolytic enzyme alpha-enolase (ENO1) is the most frequently recognized antigen (i.e. 54% of CLL sera). We show that ENO1 is upregulated in the proliferating B-cell fraction of CLL lymph nodes. In CLL cells of the peripheral blood, ENO1 is exclusively expressed at the intracellular level, whereas it is exposed on the surface of apoptotic leukemic cells.

From the clinical standpoint, patients with progressive CLL show a higher number of antigen recognitions compared to patients with stable disease. Consistently, the anti-ENO1 antibodies are prevalent in sera from patients with progressive disease and their presence is predictive of a shorter time to first treatment. This clinical inefficacy associates with the inability of patients’ sera to trigger complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity against leukemic cells.

Together, these results indicate that antibody responses toward tumor-derived antigens are frequently detectable in sera from patients with CLL, but they are expression of a disrupted immune system and unable to hamper disease progression.

Inflammatory myopathies and lymphoma

The inflammatory myopathies comprise a group of immune-mediated muscle diseases. Lymphoma is a term for a variety of lymphatic system malignancies. Autoimmune diseases and lymphoproliferative malignancies share a complex bidirectional relationship. A causal relationship between inflammatory mypathies and lymphoma has not been established. The diagnosis/treatment of inflammatory myopathy usually precedes the detection/diagnosis of lymphoma. Immune system dysregulation presumably underlies the evolution of lymphoma in patients with inflammatory myopathies. Inflammatory activity with chronic B-cell activation and/or antigen stimulation is deemed the major risk factor for lymphoma in patients with autoimmunity. A "paraneoplastic" phenomenon or the effects of immunosuppressive therapy may be alternative immune-based mechanisms. In chronic lymphocytic leukemia immune system disturbance rarely results in non-hematological autoimmune disease, including inflammatory myopathies.

Evaluation of Periodontal Parameters in Patients with Early Stage Chronic Lymphocytic Leukemia

OBJECTIVE

To assess periodontal conditions in patients with early stage CLL and to compare it with the periodontal status of age matched healthy controls and to analyze the relationship between periodontal and hematological parameters in CLL patients.

MATERIALS AND METHODS

60 subjects were examined: 30 patients with CLL Rai 0 (test group) and 30 age-matching healthy individuals (control group). The exclusion criteria were: presence of other systemic disease or condition (e.g. diabetes), history of treatment for periodontitis, use of antibiotics during the last 3 months, use of medications. Socio-demographic data were obtained by means of a questionnaire. Participants with at least 8 teeth underwent a full mouth examination assessing API, PBI, PPD, REC and CAL. Medical data for CLL patients were collected from the patients' records, while hematological data were obtained from the hemogram.

RESULTS

Difference between groups was statistically significant for age, number of teeth and frequency of dental checkups (p<0.05). Patients with CLL had significantly higher average values of periodontal indices (API 0.81±0.18; PBI 2.72±0.68; PPD 3.40±0.53; REC 1.95±0.87, CAL 4.37±0.80) compared to the control group (API 0.69±0.15; PBI 1.91±0.45; PPD 2.51±0.40; REC 0.99±0.54; CAL 3.00±0.58). The correlation coefficients between age and periodontal indices showed statistically significance between age and REC (r=0.357; p<0.01), and age and CAL (r=0.295; p<0.05). Age was not statistically significant covariate for CAL (F=2.205; p>0.05), only for REC (F=4.601; p<0.05). After the removal of the statistical effect of age, the difference in REC between CLL and control group remained statistically significant (F=19.732; p<0.01; eta(2)=0.287). Statistically significant association between periodontal and hematological parameters in CLL patients was not found (p>0.05).

CONCLUSION

The results of this study showed that patients with CLL had worse periodontal status compared to healthy subjects. Causal relationship between periodontal and hematological parameters was not proved.

Lymphoma-associated dysimmune polyneuropathies

Lymphoma consists of a variety of malignancies of lymphocyte origin. A spectrum of clinical peripheral neuropathy syndromes with different disease mechanisms occurs in about 5% of lymphoma patients. There exists a complex inter-relationship between lymphoproliferative malignancies and autoimmunity. An imbalance in the regulation of the immune system presumably underlies various immune-mediated neuropathies in patients with lymphoma. This article reviews lymphoma and more-or-less well-defined dysimmune neuropathy subgroups that are caused by humoral and/or cell-mediated immune disease mechanisms directed against known or undetermined peripheral nerve antigens.

B-CLL cells acquire APC- and CTL-like phenotypic characteristics after stimulation with CpG ODN and IL-21

CpG oligodeoxynucleotides (CpG) and IL-21 are two promising agents for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). Recently, we reported that the combination of CpG and IL-21 (CpG/IL-21) can induce granzyme B (GrB)-dependent apoptosis in B-CLL cells. Here, we demonstrate that treatment of B-CLL cells with CpG and IL-21 results in the development of antigen-presenting cell (APC)-like cells with cytotoxic features. These properties eventually give rise to B-CLL cell apoptosis, independently of their cytogenetic phenotype, whereas normal B-cell survival is not negatively affected by CpG/IL-21. APC- and CTL-typical molecules found to be up-regulated in CpG/IL-21-stimulated B-CLL cells include GrB, perforin, T-bet, monokine-induced by IFN-γ and IFN-γ-inducible protein 10 (IP-10), as well as molecules important for cell adhesion, antigen cross-presentation and costimulation. Also induced are molecules involved in GrB induction, trafficking and processing, whereas the GrB inhibitor Serpin B9 [formerly proteinase inhibitor-9 (PI-9)] is down-modulated by CpG/IL-21. In conclusion, CpG/IL-21-stimulated B-CLL cells acquire features that are reminiscent of killer dendritic cells, and which result in enhanced immunogenicity, cytotoxicity and apoptosis. Our results provide novel insights into the aberrant immune state of B-CLL cells and may establish a basis for the development of an innovative cellular vaccination approach in B-CLL.

BTK inhibitors in chronic lymphocytic leukemia: a glimpse to the future

The treatment of chronic lymphocytic leukemia (CLL) with inhibitors targeting B cell receptor signaling and other survival mechanisms holds great promise. Especially the early clinical success of Ibrutinib, an irreversible inhibitor of Bruton's tyrosine kinase (BTK), has received widespread attention. In this review we will focus on the fundamental and clinical aspects of BTK inhibitors in CLL, with emphasis on Ibrutinib as the best studied of this class of drugs. Furthermore, we summarize recent laboratory as well as clinical findings relating to the first cases of Ibrutinib resistance. Finally, we address combination strategies with Ibrutinib, and attempt to extrapolate its current status to the near future in the clinic.

Bendamustine-induced immune hemolytic anemia in a chronic lymphocytic leukemia patient: A case report and review of the literature

Bendamustine is an alkylating agent approved for the treatment of chronic lymphocytic leukemia (CLL) and B-cell non-Hodgkin lymphoma. There are scant reports on bendamustine-induced immune hemolytic anemia occurring mainly in CLL patients. We report a case of immune hemolytic anemia that developed after exposure to bendamustine in a 70-year-old female with CLL who was previously exposed to fludarabine. Previous exposure to fludarabine is a common finding in the majority of reported cases of bendamustine drug-induced immune hemolytic anemia (DIIHA), including our case. Bendamustine should be suspected as the cause of any hemolytic anemia that develops while on this drug, especially in CLL patients treated previously with fludarabine.

Short communication: bendamustine-related hemolytic anemia in chronic lymphocytic leukemia

PURPOSE

Immune hemolytic anemia (IHA) may complicate the course of chronic lymphocytic leukemia (CLL), especially in patients with advanced disease, and as a complication of treatment with chlorambucil or fludarabine. Bendamustine, a novel agent with both alkylating and purine-analog properties, was approved in the USA for use in CLL in 2008. Since then, clinical data on its adverse events are accumulating. IHA related to bendamustine was seldom described and is thus reported and reviewed.

METHODS

We assessed five cases of CLL patients complicated by IHA, out of 31 treated with bendamustine for a relapse of their disease. Also reviewed are previous case reports in the literature.

RESULTS AND CONCLUSIONS

Bendamustine-related IHA is more common than suspected (16 %). No such cases were found in non-CLL patients. Personal history of fludarabine-triggered AIHA may be a risk factor for this complication (recorded in 4/5 patients, 80 %). The mechanism is thought to be related to the loss of T cell regulatory control as described for other agents. Physicians using bendamustine for the treatment for CLL should be aware of this complication.

Autoantigen can promote progression to a more aggressive TCL1 leukemia by selecting variants with enhanced B-cell receptor signaling

(Auto)antigen engagement by the B-cell receptor (BCR) and possibly the sites where this occurs influence the outcome of chronic lymphocytic leukemia (CLL). To test if selection for autoreactivity leads to increased aggressiveness and if this selection plays out equally in primary and secondary tissues, we used T-cell leukemia (TCL)1 cells reactive with the autoantigen phosphatidylcholine (PtC). After repeated transfers of splenic lymphocytes from a single mouse with oligoclonal PtC-reactive cells, outgrowth of cells expressing a single IGHV-D-J rearrangement and superior PtC-binding and disease virulence occurred. In secondary tissues, increased PtC-binding correlated with enhanced BCR signaling and cell proliferation, whereas reduced signaling and division of cells from the same clone was documented in cells residing in the bone marrow, blood, and peritoneum, even though cells from the last site had highest surface membrane IgM density. Gene-expression analyses revealed reciprocal changes of genes involved in BCR-, CD40-, and PI3K-signaling between splenic and peritoneal cells. Our results suggest autoantigen-stimulated BCR signaling in secondary tissues promotes selection, expansion, and disease progression by activating pro-oncogenic signaling pathways, and that--outside secondary lymphoid tissues--clonal evolution is retarded by diminished BCR-signaling. This transferrable, antigenic-specific murine B-cell clone (TCL1-192) provides a platform to study the types and sites of antigen-BCR interactions and genetic alterations that result and may have relevance to patients.

Critical role of the IgM Fc receptor in IgM homeostasis, B-cell survival, and humoral immune responses

IgM antibodies have been known for decades to enhance humoral immune responses in an antigen-specific fashion. This enhancement has been thought to be dependent on complement activation by IgM-antigen complexes; however, recent genetic studies render this mechanism unlikely. Here, we describe a likely alternative explanation; mice lacking the recently identified Fc receptor for IgM (FcμR) on B cells produced significantly less antibody to protein antigen during both primary and memory responses. This immune deficiency was accompanied by impaired germinal center formation and decreased plasma and memory B-cell generation. FcμR did not affect steady-state B-cell survival but specifically enhanced the survival and proliferation induced by B-cell receptor cross-linking. Moreover, FcμR-deficient mice produced far more autoantibodies than control mice as they aged, suggesting that FcμR is also required for maintaining tolerance to self-antigens. Our results thus define a unique pathway mediated by the FcμR for regulating immunity and tolerance and suggest that IgM antibodies promote humoral immune responses to foreign antigen yet suppress autoantibody production through at least two pathways: complement activation and FcμR.

Toll-like Receptors in Chronic Lymphocytic Leukemia

Toll-like receptors belong to the pattern recognition receptors family present on a variety of immune cells including normal and malignant B-cells. They act as immediate molecular sentinels of innate immunity but also act as a molecular bridge between the innate and the adaptive immune response; distinct Toll-like receptors are able to bind specific pattern molecules of bacteria, viruses and autoantigens. In this review we will briefly introduce the Toll-like receptor family and their expression pattern, signaling and function in the B cell context; following we will summarize the published data on TLR in chronic lymphocytic leukemia, and we will discuss their emerging role in the modulation of leukemia pathobiology.

Alterations in TP53, cyclin D2, c-Myc, p21WAF1/CIP1 and p27KIP1 expression associated with progression in B-CLL

B-cell chronic lymphocytic leukaemia (B-CLL) originates from B lymphocytes that may differ in the activation level, maturation state or cellular subgroups in peripheral blood. Tumour progression in CLL B cells seems to result in gradual accumulation of the clone of resting B lymphocytes in the early phases (G0/G1) of the cell cycle. The G1 phase is impaired in B-CLL. We investigated the gene expression of five key cell cycle regulators: TP 53, c-Myc, cyclin D2, p21WAF1/CIP1 and p27KIP1, which primarily regulate the G1 phase of the cell cycle, or S-phase entry and ultimately control the proliferation and cell growth as well as their role in B-CLL progression. The study was conducted in peripheral blood CLL lymphocytes of 40 previously untreated patients. Statistical analysis of correlations of TP53, cyclin D2, c-Myc, p21WAF1/CIP1 and p27KIP1 expressions in B-CLL patients with different Rai stages demonstrated that the progression of disease was accompanied by increases in p53, cyclin D2 and c-Myc mRNA expression. The expression of p27KIP1 was nearly statistically significant whereas that of p21 WAF1/CIP1 showed no such correlation. Moreover, high expression levels of TP53 and c-Myc genes were found to be closely associated with more aggressive forms of the disease requiring earlier therapy.

Lack of TIR8/SIGIRR triggers progression of chronic lymphocytic leukemia in mouse models

Inflammation is involved in the initiation and progression of several chronic lymphoid malignancies of B-cell type. Toll-like receptors (TLR) are transmembrane inflammatory receptors that on recognition of pathogen-associated molecular patterns trigger an innate immune response and bridge the innate and adaptive immune response by acting as costimulatory signals for B cells. Fine tuning of TLR and IL-1R-like (ILR) activity is regulated by TIR8 (SIGIRR), a transmembrane receptor of the TLR/ILR family which inhibits other family members. To test the hypothesis that TLR and/or ILR may play a role in the natural history of chronic B-cell tumors, we crossed Eμ-TCL1 transgenic mice, a well established model of chronic lymphocytic leukemia (CLL), with mice lacking the inhibitory receptor TIR8 that allow an unabated TLR-mediated stimulation. We here report that in the absence of TIR8 the appearance of monoclonal B-cell expansions is accelerated and mouse life span is shortened. The morphology and phenotype of the mouse leukemic expansions reproduce the progression of human CLL into an aggressive and frequently terminal phase characterized by the appearance of prolymphocytes. This study reveals an important pathogenetic implication of TLR in CLL development and progression.

Chronic lymphocytic leukemia and autoimmunity: a systematic review

Chronic lymphocytic leukemia is frequently associated with immune disturbances. The relationship between chronic lymphocytic leukemia and autoimmune cytopenias, particularly autoimmune hemolytic anemia and immune thrombocytopenia, is well established. The responsible mechanisms, particularly the role of leukemic cells in orchestrating the production of polyclonal autoantibodies, are increasingly well understood. Recent studies show that autoimmune cytopenia is not necessarily associated with poor prognosis. On the contrary, patients with anemia or thrombocytopenia due to immune mechanisms have a better outcome than those in whom these features are due to bone marrow infiltration by the disease. Moreover, fears about the risk of autoimmune hemolysis following single agent fludarabine may no longer be appropriate in the age of chemo-immunotherapy regimens. However, treatment of patients with active hemolysis may pose important problems needing an individualized and clinically sound approach. The concept that autoimmune cytopenia may precede the leukemia should be revisited in the light of recent data showing that autoimmune cytopenia may be observed in monoclonal B-cell lymphocytosis, a condition that can only be detected by using sensitive flow cytometry techniques. On the other hand, there is no evidence of an increased risk of non-hemic autoimmune disorders in chronic lymphocytic leukemia. Likewise, there is no epidemiological proof of an increased risk of chronic lymphocytic leukemia in patients with non-hemic autoimmunity. Finally, since immune disorders are an important part of chronic lymphocytic leukemia, studies aimed at revealing the mechanisms linking the neoplastic and the immune components of the disease should help our understanding of this form of leukemia.

The New Zealand black mouse as a model for the development and progression of chronic lymphocytic leukemia

BACKGROUND

Similar to a subset of human patients who progress from monoclonal B lymphocytosis (MBL) to chronic lymphocytic leukemia (CLL), New Zealand Black (NZB) mice have an age-associated progression to CLL. The murine disease is linked to a genetic abnormality in microRNA mir-15a/16-1 locus, resulting in decreased mature miR-15a/16.

METHODS

Spleens of aging NZB were analyzed for the presence of B-1 cells via flow cytometry and for the presence of a side population (SP) via the ability of cells to exclude Hoechst 33342 dye. The SP was assayed for the presence of hyperdiploid B-1 clones and for the ability to differentiate into B-1 cells in vitro and transfer disease in vivo. In addition, enhanced apoptosis of chemoresistant NZB B-1 cells was examined by restoring miR-16 levels in nutlin-treated cells.

RESULTS

Aging NZB mice develop a B-1 expansion and clonal development that evolves from MBL into CLL. An expansion in SP is also seen. Although the SP did contain increased cells with stem cell markers, they lacked malignant B-1 cells and did not transfer disease in vivo. Similar to B-1 cells, splenic NZB SP also has decreased miR-15a/16 when compared with C57Bl/6. Exogenous addition of miR-15a/16 to NZB B-1 cells resulted in increased sensitivity to nutlin.

CONCLUSION

NZB serve as an excellent model for studying the development and progression of age-associated CLL. NZB SP cells do not seem to contain cancer stem cells, but rather the B-1 stem cell. NZB B-1 chemoresistance may be related to reduced miR-15a/16 expression.

Correcting miR-15a/16 genetic defect in New Zealand Black mouse model of CLL enhances drug sensitivity

Alterations in the human 13q14 genomic region containing microRNAs mir-15a and mir-16-1 are present in most human chronic lymphocytic leukemia (CLL). We have previously found the development of CLL in the New Zealand Black murine model to be associated with a point mutation in the primary mir-15a/16-1 region, which correlated with a decrease in mature miR-16 and miR-15a levels. In this study, addition of exogenous miR-15a and miR-16 led to an accumulation of cells in G(1) in non-New Zealand Black B cell and New Zealand Black-derived malignant B-1 cell lines. However, the New Zealand Black line had significantly greater G(1) accumulation, suggesting a restoration of cell cycle control upon exogenous miR-15a/16 addition. Our experiments showed a reduction in protein levels of cyclin D1, a miR-15a/16 target and cell cycle regulator of G(1)/S transition, in the New Zealand Black cell line following miR-15a/16 addition. These microRNAs were shown to directly target the cyclin D1 3' untranslated region using a green fluorescent protein lentiviral expression system. miR-16 was also shown to augment apoptosis induction by nutlin, a mouse double minute 2 (MDM2) antagonist, and genistein, a tyrosine kinase inhibitor, when added to a B-1 cell line derived from multiple in vivo passages of malignant B-1 cells from New Zealand Black mice with CLL. miR-16 synergized with nutlin and genistein to induce apoptosis. Our data support a role for the mir-15a/16-1 cluster in cell cycle regulation and suggest that these mature microRNAs in both the New Zealand Black model and human CLL may be targets for therapeutic efficacy in this disease.

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.

Malignancies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypical systemic autoimmune disease, characterized by a wide array of symptoms and organ involvements, leading to varying disease courses and outcome, and ranging from mild to severe types. In patients with SLE, the incidence and risk of malignancy development is increased, and mostly non-Hodgkin's lymphoma (NHL), cervical cancer, as well as bronchial carcinomas occur. Besides others, the common genetic predisposition, chronic antigen stimulus, disproportional immune responses, as well as the chronic administration of immunosuppressive medications can contribute to the development of malignancies in lupus. In this review we present the molecular pathology, as well as the epidemiological and clinical aspects of malignancies in patients with SLE.

Malignancies and catastrophic anti-phospholipid syndrome

The catastrophic anti-phospholipid (Asherson's) syndrome (CAPS) is characterised by the rapid chronological development of fulminant thrombotic complications that predominantly affect small vessels and differs from the anti-phospholipid syndrome in its accelerated systemic involvement leading to multi-organic failure. Malignancy may play a pathogenic role in patients with CAPS, whereas infections are more important as triggering factors in patients without malignancies. CAPS patients with malignancies are generally older than CAPS patients without malignancies; they generally have the worst prognosis of the entire CAPS cohort.

Autoimmune pancytopenia following combination chemotherapy for chronic lymphocytic leukaemia: Figure 1

Autoimmune haemolysis or thrombocytopenia can complicate purine nucleoside monotherapy for chronic lymphocytic leukaemia (CLL), but Evans syndrome is rare. This is a report of the occurrence of pancytopenia secondary to a unique combination of red cell aplasia with autoimmune thrombocytopenia and neutropenia in a patient with CLL following treatment with fludarabine and cyclophosphamide. This case is unusual for the simultaneous targeting of three haemopoietic lineages by immune dysfunction following fludarabine and cyclophosphamide, which is a treatment regimen believed to reduce autoimmune haematological toxicity in CLL.

Tumor-associated antigens in systemic sclerosis and systemic lupus erythematosus: associations with organ manifestations, immunolaboratory markers and disease activity indices

BACKGROUND

Some tumor-associated antigens (TAAs) are expressed on inflammatory cells. We previously detected increased production of CA15-3, CA19-9 and CA125 in rheumatoid arthritis (RA). The production of some TAAs may also be increased in patients with systemic sclerosis (SSc), systemic lupus erythematosus (SLE) and other connective tissue diseases. Some of these TAAs contain sialylated carbohydrate motifs and they are involved in tumor-associated cell adhesion and metastasis.

OBJECTIVES

We assessed levels of TAAs in the sera of SSc, SLE patients, patients with infectious diseases and healthy subjects. Serum TAA levels were correlated with each other, as well as with disease activity markers and organ involvement.

METHODS

TAAs including CEA, CA15-3, CA72-4, CA125 and CA19-9 were assessed by immunoassay in the sera of 92 patients with SSc, 40 patients with SLE, 50 age- and sex-matched healthy controls, as well as with 40 patients with current bacterial or viral infections. Normal upper limits for these TAAs were 3.4 mg/l, 25 kU/l, 6.9 kU/l, 35 kU/l and 34 kU/l, respectively.

RESULTS

There were significantly more SSc patients showing abnormally high levels of CA19-9 (8.8% vs 2.0%), CA125 (11.0% vs 6.0%) and CA15-3 (28.4% vs 14.0%) in comparison to controls (p < 0.05). In SLE, significantly more patients had elevated levels of CEA (32.5% vs 20.0%), CA19-9 (7.5% vs 2.0%), CA125 (15.0% vs 6.0%) and CA72-4 (15.0% vs 8.0%) than did controls (p < 0.05). The mean absolute serum levels of CEA (6.6+/-1.7 vs 1.8+/-1.4 mg/l) and CA15-3 (22.9 +/- 1.8 vs 18.6 +/- 2.2 kU/l) were also significantly higher in SSc compared to controls (p < 0.05). We found numerous correlations between the serum levels of different TAAs within the SSc and SLE population. Among SSc patients, serum CEA (R = 0.290; p = 0.005), CA15-3 (R = 0.260; p = 0.020) and CA19-9 (R = 0.257; p = 0.013) correlated with renal involvement. Serum CA15-3 also correlated with joint involvement (R = 0.329; p = 0.003), ANA positivity (R = 0.288; p = 0.010) and CRP levels (R = 0.407; p < 0.001). Within the SLE population, serum CA72-4 correlated with central nervous involvement (R = 0.624; p = 0.004) and CA125 correlated with the SLEDAI composite activity index (R = 0.666; p = 0.002). Patients with infections exerted serum TAA patterns similar to healthy controls.

CONCLUSION

The concentration of some TAAs may be elevated in the sera of patients with SSc or SLE in comparison to healthy subjects. Pathogenically, most of these TAAs contain carbohydrate motifs and thus they may be involved in inflammation-associated adhesive events. Furthermore, the production of some TAAs may correlate with organ involvement or disease activity in scleroderma or lupus.

Intrinsic and treatment-related immune alterations in chronic lymphocytic leukaemia and their impact for clinical practice

BACKGROUND

Chronic lymphocytic leukaemia patients harbour important impairments in both their cellular- and humoral-mediated immunity, which accounts for their notorious susceptibility to a multitude of infections and various autoimmune cytopenias. It has also been shown that the rate of second cancers is increased in chronic lymphocytic leukaemia.

OBJECTIVE

The aim of this study was to review the immune alterations in untreated and treated chronic lymphocytic leukaemia and define their impact for clinical practice.

METHODS

The author gives a comprehensive review of the most relevant preclinical and clinical studies pertaining to various immune abnormalities and infectious complications in both untreated and treated chronic lymphocytic leukaemia. Landmark clinical trials involving the contemporary chronic lymphocytic leukaemia chemo- and immunotherapies, alone or in combination, as well as the main epidemiological studies establishing the increased rate of second cancers in chronic lymphocytic leukaemia are also discussed.

RESULTS/CONCLUSIONS

Iatrogenic immunosuppression in chronic lymphocytic leukaemia alters the pattern of opportunistic infections, can cause autoimmune cytopenias and might further increase the rate of second malignancies in patients whose disease already places them at a greater risk. Careful consideration of existing risk factors in chronic lymphocytic leukaemia could establish the optimal screening and follow-up schedule for chronic lymphocytic leukaemia patients as its therapeutics evolves.

Disease-Specific Complications of Chronic Lymphocytic Leukemia

The majority of disease-specific complications in chronic lymphocytic leukemia (CLL), notably infection and autoimmunity, relate to the underlying alterations in immune function. Both cellular and humoral immunity are impaired with qualitative and quantitative defects in B cells, T cells, NK cells, neutrophils and the monocyte/macrophage lineage. Virtually all patients have reduced immunoglobulin levels, even in early stages, and this is associated with an increased frequency and severity of infection. Although prophylactic intravenous immunoglobulin may be of clinical benefit in selected patients, it does not reduce mortality and is certainly not cost-effective. Autoimmune complications occur in up to a quarter of CLL patients and predominantly target blood cells. Autoimmune hemolytic anemia (AHA) is the most common manifestation; immune thrombocytopenia, pure red cell aplasia and autoimmune neutropenia are less common, while non-hematological autoimmunity is rare. The UK CLL4 trial is the largest prospective trial in CLL to examine the significance of both a positive direct antiglobulin test (DAT) and AHA. The study confirmed the usefulness of the DAT in predicting the development of AHA or not, demonstrated that AHA occurred more frequently in patients receiving treatment with chlorambucil or fludarabine alone compared with the combination of fludarabine and cyclophosphamide, and showed that a positive DAT and the development of AHA were poor prognostic markers. Management of CLL-associated autoimmunity rests on good supportive care and the use of immunosuppressive therapies such as steroids and cyclosporine. Splenectomy remains useful, and monoclonal antibodies (rituximab and alemtuzumab) have given promising results.