Sequencing-based analysis of clonal evolution of 25 mantle cell lymphoma patients at diagnosis and after failure of standard immunochemotherapy.

Our knowledge of genetic aberrations, that is, variants and copy number variations (CNVs), associated with mantle cell lymphoma (MCL) relapse remains limited. A cohort of 25 patients with MCL at diagnosis and the first relapse after the failure of standard immunochemotherapy was analyzed using whole-exome sequencing. The most frequent variants at diagnosis and at relapse comprised six genes: TP53, ATM, KMT2D, CCND1, SP140, and LRP1B. The most frequent CNVs at diagnosis and at relapse included TP53 and CDKN2A/B deletions, and PIK3CA amplifications. The mean count of mutations per patient significantly increased at relapse (n = 34) compared to diagnosis (n = 27). The most frequent newly detected variants at relapse, LRP1B gene mutations, correlated with a higher mutational burden. Variant allele frequencies of TP53 variants increased from 0.35 to 0.76 at relapse. The frequency and length of predicted CNVs significantly increased at relapse with CDKN2A/B deletions being the most frequent. Our data suggest, that the resistant MCL clones detected at relapse were already present at diagnosis and were selected by therapy. We observed enrichment of genetic aberrations of DNA damage response pathway (TP53 and CDKN2A/B), and a significant increase in MCL heterogeneity. We identified LRP1B inactivation as a new potential driver of MCL relapse.

Clinical value of ALK and CD30 expression in mature systemic T cell lymphomas: analysis from the Czech Lymphoma Study Group database (NIHIL).

Mature T cell lymphomas (MTCLs) have worse prognosis, and in contrast to B cell lymphomas, there is no universal marker like CD20 with exception of ALK and CD30, which are present in proportion of MTCL only. Up to now, ALK is traditionally associated with good prognosis in ALCLs, and there are some evidences that CD30-positive T cell or B cell lymphomas have better prognosis. In our retrospective, population-based analysis, we analyzed the real clinical value of ALK and CD30 in the most frequent MTCL subtypes. Between 2000 and 2017, we identified 732 patients with newly diagnosed ALCL, AITL, or PTCL-NOS. Among them, 207 ALCL patients were with known ALK, whereas 61 AITL and 238 PTCL-NOS with known CD30 expression. There were 69/207 (33.3%) ALK + ALCLs, who displayed better 5-year PFS (65.6% vs. 36.2%) (p .001) and 5-year OS (71.5% vs. 45.9%) (p .002) compared to ALK - ; ALK + patients were significantly younger (median 48 vs. 60 years; p < 0.001). For patients ≥ 60 years, 5-year PFS (38.5% vs. 31.2%) and 5-year OS (38.5% vs. 39.6%) were similar between ALK + vs. ALK - patients. For AITL and PTCL-NOS, there were 44/61 (72.1%) and 120/238 (50.4%) CD30 + samples, and difference in CD30 expression was significant (p .02). AITL patients had 5-year OS of 43.8% vs. 55.7% (p 0.848) and 5-year PFS of 36.7% vs. 29.4% (p .624) for CD30 + vs. CD30 - patients, whereas PTCL-NOS had 5-year OS of 35.7% vs. 34.3% (p .318) and 5-year PFS of 29.3% vs. 22.5% (p.114) for CD30 + vs. CD30 - cases. We conclude that ALK in ALCLs (≥ 60 years) and CD30 expression in PCTL-NOS and AITL have only limited prognostic value.

PD-1, PD-L1 and PD-L2 Expression in Mantle Cell Lymphoma and Healthy Population.

Cell surface expression of PD-1, PD-L1 and PD-L2 immune checkpoints on B and T cells obtained from patients with mantle cell lymphoma shows ambiguous results across many studies and creates obstacles for the implementation of immune checkpoint inhibitors into the therapy of mantle cell lymphoma. Using multiparameter flow cytometry we analysed surface expression of PD-1, PD-L1 and PD-L2 molecules on B and T cells of 31 newly diagnosed mantle cell lymphomas and compared it with the results of 26 newly diagnosed chronic lymphocytic leukaemias and 20 healthy volunteers. To gain insight into the age-dependent changes of surface expression of these immune checkpoints, flow cytometric subanalysis of 30 healthy volunteers of 25-93 years of age was conducted. Overall, we demonstrated weak surface expression of PD-1, PD-L1 and PD-L2 on B and T cells of mantle cell lymphoma patients (< 10 % when compared to healthy individuals). A significant age-dependent increase in the expression of PD-1 and its ligand PD-L2 was observed in healthy volunteers. Our results suggest that neither PD-1 nor its ligands represent relevant druggable targets for the therapy of mantle cell lymphoma. The observed age-dependent changes in healthy population could impact efficiency of immune checkpoint inhibitors and could be at least partly connected with increased incidence of cancer with age.

Anti-CD38 Therapy with Daratumumab for Relapsed/Refractory CD20-Negative Diffuse Large B-Cell Lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common and one of the most aggressive subtypes of non-Hodgkin's lymphomas. Front-line therapy consists of chemotherapy in combination with anti-CD20 monoclonal antibody rituximab. Relapses after rituximab-based regimen have poor prognosis and call for new treatment options. Immunohistochemistry analysis of relapsed DLBCL often reveal CD20-negative lymphoma, which limits repeated use of rituximab in combination with salvage chemotherapy. CD38 is a surface antigen that binds to CD38, CD31/PECAM-1 and hyaluronic acid. CD38 is an important mediator of signal transmission from the microenvironment into the cell. Anti-CD38 monoclonal antibody daratumumab has been approved for the treatment of multiple myeloma. Expression of CD38 on the surface of DLBCL is highly variable (compared to strong expression on myeloma cells), but can be easily assessed by flow cytometry or immunohistochemistry. A patient-derived xenograft (PDX) model of CD20-negative, CD38-positive DLBCL derived from a patient with rituximab-refractory DLBCL was used for in vivo experiments. We demonstrated that daratumumab suppressed growth of subcutaneous PDX tumours significantly more effectively than rituximab. Analysis of tumours obtained from mice treated with daratumumab revealed down-regulation of surface CD38, suggesting endocytosis of CD38-daratumumab complexes. The results suggest a potential clinical use of daratumumab in combination with salvage chemotherapy in patients with relapses of CD20-negative DLBCL. In addition, daratumumab might potentially serve as a suitable antibody moiety for derivation of antibodydrug conjugates for the targeted delivery of toxic payloads to the lymphoma cells.

Cyclin D1 mRNA as a molecular marker for minimal residual disease monitoring in patients with mantle cell lymphoma.

Chromosomal translocation t(11;14)(q13;q32) is a characteristic molecular marker of mantle cell lymphoma (MCL) and leads to the fusion of the immunoglobulin heavy chain enhancer-promoter with the cyclin D1 gene. Both aberrant cyclin D1 expression and underlying chromosomal aberration may be used as molecular targets for monitoring minimal residual disease (MRD). The present study aims to assess the usefulness of quantitative cyclin D1 gene expression compared to the standardised but more technologically demanding DNA-based method for immunoglobulin heavy chain (IGH) or t(11;14) clone-specific gene rearrangement quantification in a cohort of bone marrow (BM) and peripheral blood (PB) samples from patients with MCL. We simultaneously evaluated DNA-MRD and cyclin D1 expression levels in 234 samples from 57 patients. We observed that both in DNA-MRD positive and negative BM/PB pairs from the same time points the expression levels of cyclin D1 are lower in PB than in BM (median 19×, BM/PB range 0.41-352). The correlation of cyclin D1 transcript levels with DNA-MRD or with flow cytometry was good only in samples with a very high infiltration. In DNA-MRD-negative BM samples, we observed a significant heterogeneity of cyclin D1 expression (in the range of more than three orders of magnitude). This is in contrast to previous reports demonstrating the usefulness of cyclin D1 for MRD monitoring that did not use DNA-based method as a reference. In PB, the specificity of cyclin D1 expression was better due to a lower physiological background. In conclusion, we show that cyclin D1 is unsuitable for MRD monitoring in BM.

Single-agent cytarabine is insufficient for the treatment of human mantle cell lymphoma in mouse xenograft model.

Mantle cell lymphoma is an aggressive type of B-cell non-Hodgkin lymphoma with adverse prognosis. It was demonstrated that alternation of CHOP and DHAP chemotherapy improved outcome of mantle cell lymphoma patients. However, which components of DHAP, cisplatin, cytarabine, or both, were responsible for the improved outcome remained unclear. To answer this question, antitumor efficacies of equally toxic doses of cytarabine, cisplatin, and three different combinations were compared in vivo using mouse xenograft models of mantle cell lymphoma. We demonstrated that cisplatin, alone or with cytarabine, is significantly superior to single-agent cytarabine in both eliminating lymphoma cells and suppressing their proliferation rate.

Comparison of Plasma Osteopontin Levels between Patients with Borderline Ovarian Tumours and Serous Ovarian Carcinoma.

Osteopontin (OPN) is a novel biomarker of various cancers including ovarian carcinoma. OPN is a promising adjunct to a major biomarker of ovarian cancer, CA125, in diagnosis, differential diagnosis and prognosis. The aim of our study was to measure the plasma level of OPN and CA125 in patients with borderline ovarian tumours (BOTs), serous ovarian carcinoma, and controls to determine its potential role in the differential diagnosis between serous ovarian carcinoma and BOT. The plasma samples of 66 women were analysed using Luminex technology, designed to simultaneously measure multiple specific protein targets. The mean OPN plasma level for the control group was 23.3 ng/ml; for BOT 26.3 ng/ml; and for patients with serous ovarian carcinoma 59.5 ng/ml. Specifically, there was a significant difference between the OPN levels in patients with ovarian carcinoma and BOT (P < 0.001) as well as controls (P < 0.001). There was no difference between the mean levels of OPN in patients with BOT and the control group (P = 0.286). Using the receiver operating characteristic (ROC), we determined the utility of OPN and CA125 to differentiate between BOT and serous ovarian carcinoma. The area under the ROC curve (AUC) for OPN was 0.793 (95% confidence interval (CI) 0.669-0.917, P < 0.001) and for CA125 0.766 (95% CI 0.626-0.907, P = 0.002). Based on our data, we suggest that OPN can be used as a possible differential diagnostic biomarker to distinguish between malignant serous ovarian carcinoma and BOT.

[Staging and Treatment Response Evaluation in Malignant Lymphomas - Czech Lymphoma Study Group Recommendations According to Criteria Revised in 2014 (Lugano Classification)]. / Hodnocení klinického stadia a lécebné odpovedi u maligních lymfomu - doporucení Kooperativní lymfomové skupiny na základe revidovaných kritérií z roku 2014 (Luganská klasifikace).

BACKGROUND: Recent advances in the use of the imaging modalities, especially PET/CT, and their utilization for determining clinical stage (CS) and assessment treatment response (TR) in malignant lymphomas, along with development of prognostic tools and new treatment modalities, formed the basis for the revised criteria for evaluating CS and TR (published as the Lugano classification, 2014). MATERIALS AND METHODS: The authors summarize the new Lugano recommendations (published in 2014) and the changes from the criteria published in 2007. Moreover, discussion of the changes places emphasis on practical use. The practicality of the Lugano classification, 2014 was the subject of consensus meeting at the annual meeting of the Cooperative Lymphoma Study Group (CLSG) in March 2015. This study reports the final consensus. The CLSG recommends use of the Lugano classification, 2014, but recommends some modifications. CONCLUSIONS: Standardization of the criteria used to determine CS and TR in malignant lymphomas has led to improvements in initial staging and assessment of TR. The criteria are helpful for unifying response assessment in clinical trials and simplify the work of regulatory agencies (e.g., the EMA and the Czech State Institute for Drug Control) when registering new drugs. It also allows evaluation of treatment outcomes outside clinical trials, for example within the CLSG prospective registry of patients with newly diagnosed lymphoma. KEY WORDS: malignant lymphoma - computed tomography - positron emission tomography - staging - treatment responseThis work was supported by the grant Prvouk P27/2012 of the Third Faculty of Medicine, Charles University in Prague and by the grant of the Czech Lymphoma Study Group No. NT12193-5/2011.The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 24. 1. 2016Accepted: 16. 2. 2016.

[Mantle Cell Lymphoma -  Cutting edge Dia-gnostics and Treatment Approaches]. / Lymfom z plástových bunek -  soucasný stav poznání a moznosti lécby.

BACKGROUND: Mantle cell lymphoma represents a specific subtype of B -cell non-Hodgkin lymphoma characterized on the molecular level by translocation t(11;14)(q13;q32) leading to aberrant overexpression of cyclin D1 and deregulation of the cell cycle. Despite sporadic indolent forms of mantle cell lymphoma, majority of patients present with advanced aggressive disease that requires immediate treatment. Despite chemosensitive nature of mantle cell lymphoma, approximately 10% patients present with a refractory disease, and the vast majority of patients who initially respond to therapy, relapse sooner or later. The course of mantle cell lymphoma thus represents a chronically relapsing malignancy requiring further and further lines of therapies. Prognosis of relapsed or refractory (R/ R) mantle cell lymphoma is dismal. AIM: The goal of this article is to provide a cutting -edge review of currently used diagnostic and treatment approaches for mantle cell lymphoma. RESULTS: Several key modifications of the therapeutic algorithm of mantle cell lymphoma treatment implemented in the past 10 years resulted in significantly improved prognosis of patients. The milestones in the therapy of mantle cell lymphoma include incorporation of anti-CD20 monoclonal antibody rituximab into induction therapy, intensification of polychemotherapeutic regimen including implementation of high-dose cytarabine, consolidation of response with high-dose therapy and autologous stem cell transplantation (HDT ASCT) in younger fit patients, and maintenance therapy with rituximab in the elderly patients. Besides such "optimization" of frontline therapy, introduction of novel antilymphoma agents into therapy of R/ R mantle cell lymphoma also contributed (and will contribute in the future) to improved prognosis of mantle cell lymphoma. Among these agents, there is a new cytostatic drug bendamustine, Bruton tyrosine- kinase inhibitor ibrutinib, immunomodulatory agent lenalidomide, mTOR inhibitor temsirolimus and proteasome inhibitor bortezomib. CONCLUSION: The overall survival of mantle cell lymphoma virtually doubled in the recent 10 years as a result of two key factors: 1. optimization of frontline therapy with "conventional" antilymphoma agents, and 2. brand new possibilities of therapy for R/ R mantle cell lymphoma thanks to the introduction of novel antilymphoma agents. Combinatorial approaches using most efficacious combinations of novel and "conventional" anti-mantle cell lymphoma agents will definitely lead to further improvements of survival parameters in mantle cell lymphoma patients in near future.

[Malignant Lymphomas - Past, Present and Future]. / Maligní lymfomy minulost, soucasnost a budoucnost.

This review summarizes the key steps on the way to understanding lymphoma biology and management. The history of lymphomas started in 1832 when Thomas Hodgkin first presented lymphomas. Classification of lymphoproliferative tumors has changed almost every 10 years as a reflection of deeper knowledge of this disease. Systemic therapy has developed in several steps starting by monotherapy with different chemotherapeutic agents, followed by the era of combination chemotherapy and by the rituximab era, which significantly changed the treatment paradigm. Several years ago, we entered into the fourth era characterized by many different targeted treatments. Radiotherapy remains an important part of lymphoma management. Lymphoproliferative tumors incidence is growing but mortality has started to decline starting in the year 2000 as the reflection of targeted therapy based on biology and pathogenesis.

Central nervous system involvement in mantle cell lymphoma: clinical features, prognostic factors and outcomes from the European Mantle Cell Lymphoma Network.

BACKGROUND: Central nervous system (CNS) involvement in mantle cell lymphoma (MCL) is uncommon, and the manifestations and natural history are not well described. PATIENTS AND METHODS: We present the data on 57 patients with MCL who developed CNS involvement, from a database of 1396 consecutively treated patients at 14 institutions. RESULTS: The crude incidence of CNS involvement was 4.1%, with 0.9% having CNS involvement at diagnosis. Blastoid histology, B-symptoms, elevated lactate dehydrogenase, Eastern Cooperative Group performance status ≥2 and a high Mantle Cell Lymphoma International Prognostic Index score were enriched in the cohort with CNS involvement, and the presence of ≥1 of these features defined a high-risk subset (an actuarial risk of CNS involvement 15% at 5 years) in a single-institution subset. The median time to CNS relapse was 15.2 months, and the median survival from time of CNS diagnosis was 3.7 months. The white blood cell count at diagnosis <10.9 × 109/l, treatment of CNS involvement with high-dose anti-metabolites, consolidation with stem cell transplant and achievement of complete response were all associated with improved survival. CONCLUSIONS: In MCL, CNS involvement is uncommon, although some features may predict risk. Once manifest outlook is poor; however, some patients who receive intensive therapy survive longer than 12 months.

Multi-level disruption of the extrinsic apoptotic pathway mediates resistance of leukemia cells to TNF-related apoptosis-inducing ligand (TRAIL).

Disruption of apoptotic pathways belongs to commonly reported molecular mechanisms that underlie cancer drug resistance. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL, Apo2L) is a cytokine of the TNF family with selective anti-tumor activity and minimal toxicity toward healthy tissues. Primary leukemia cells are, however, largely intrinsically resistant to TRAIL-induced apoptosis. In this study we analyzed molecular differences between TRAIL-resistant K562 cell line and TRAIL-sensitive K562 clones. We demonstrate that TRAIL-sensitive K562 cells differ from the TRAIL-resistant cell line by cell surface downregulation of TRAIL decoy receptor 1, upregulation of both TRAIL death receptors, enhanced assembly and improved functioning of the death-inducing signaling complex, and increased cytoplasmic protein expression of CASP8 and key proapoptotic BCL2 members BID, BIM, BAD and BAK. The molecular basis of the intrinsic leukemia cell TRAIL resistance thus appears a consequence of the multi-level disruption of the extrinsic apoptotic pathway. The results of this study also suggest that the leukemia TRAIL-resistance is functional, leaving a possibility of overcoming the resistance by preexposure of the leukemia cells to potent TRAIL sensitizers, e.g. BH3-mimetics.

In vivo growth of mantle cell lymphoma xenografts in immunodeficient mice is positively regulated by VEGF and associated with significant up-regulation of CD31/PECAM1.

Mantle cell lymphoma (MCL) is an aggressive lymphoma subtype with dismal prognosis. New treatments are needed to improve outcome of relapsed/ refractory disease. Recently, several drugs targeting at least partially the process of angiogenesis have been successfully tested in the therapy of MCL. Molecular mechanisms that regulate MCL-induced angiogenesis and that might represent potential new druggable targets remain, however, incompletely understood. We established two mouse models of human MCL by subcutaneous xenotransplantation of JEKO-1 and HBL-2 cell lines into immunodeficient mice. Histological analyses of xenografts confirmed their neovascularization. The growth of xenografts was significantly suppressed by single-agent therapy with bevacizumab, monoclonal antibody targeting vascular endothelial growth factor (VEGF). Subsequently, we analysed expression of 94 angiogenesis related genes in ex vivo isolated JEKO-1 and HBL-2 cells compared to in vitro growing cells using TaqMan low-density arrays. The most up-regulated genes in both JEKO-1 and HBL-2 xenografts were genes encoding platelet/endothelial cell-adhesion molecule (CD31/PECAM1), VEGF receptor 1 (FLT1), hepatocyte growth factor (HGF), angiogenin (ANG) and transcription factor PROX1. The most downregulated genes in both JEKO-1 and HBL-2 xenografts were midkine (MDK) and ephrine B2 (EPHB2). In summary, our results demonstrate an important role of angiogenesis in the biology of MCL and provide preclinical evidence of potent anti-MCL activity of bevacizumab. In addition, gene expression profiling of 94 angiogenesis-related targets revealed several in vivo up-regulated and down-regulated transcripts. The most differentially expressed target in both MCL tumours was CD31/PECAM1. Whether any of these molecules might represent a potential druggable target in MCL patients remains to be elucidated.

[Epigenetic cancer drugs and their role in anticancer therapy]. / Epigenetická cytostatika a jejich role v protinádorové lécbe

Epigenetic modification have been causally linked to cancer development and progression, and are potentially reversible by treatments with epigenetic cancer drugs. The aim of this review is to give an overview of the basic current knowledge on molecular mechanisms of epigenetic cancer drugs and their possible clinical use. Many of them are in in clinical trials. However only two demethylating agents ie. inhibitors of DNA methyltransferase (5- azacytidin and decitabin) are approved in the treatment of myelodysplastic syndrome and a few inhibitors of histonacetylase (vorinostat, romidepsin and panobinostat) are approved in the treatment of hematological malignancies, particularly in refractory or relapsed cutaneous T cell lymhoma.

[Targeted therapeutics and their role in the treatment of internal diseases]. / Cílená léciva a jejich prínos pro terapii vnitrních chorob.

Targeted therapy is a conceptual notion that should be used for such a treatment approach that has been developed based upon the known pathophysiology and/or biomarkers of a particular disease, mainly malignancies. Monoclonal antibodies and tyrosine--kinase inhibitors were among the first molecularly targeted agents. Monoclonal antibodies approach is based on targeting a biomarker expressed either on the surface of cancer cells or targeting different cytokines. Tyrosin-kinase inhibitors are directed at the druggable molecule involved in the cancer pathophysiology inhibiting aberrant tyrosin-kinase activity. Classification of targeted drugs and their use in the clinical practice is shortly reviewed.

Distinguishing of primary mediastinal B-cell lymphoma and diffuse large B-cell lymphoma using real-time quantitative polymerase chain reaction.

Primary mediastinal B-cell lymphoma (PMBL) seems to be reliably distinguished from diffuse large B-cell lymphoma (DLBCL) with microarray technology. We measured expression of Fcer2, Pdl2 and Blk genes using real-time quantitative polymerase chain reaction (RTqPCR) on formalin fixed, paraffin embedded material (FFPE) and suggested a formula to discriminate PMBL from DLBCL. For 39/82 included patients the diagnosis of PMBL was expected clinico-pathologically. Diagnosis of 10/39 and 2/43 of clinically considered PMBLs and DLBCLs, respectively, was not genetically confirmed. Compared to confirmed PMBLs, unconfirmed ones showed clinical features similar to DLBCLs, e.g. spleen infiltration (p=0,028) and decreased invasiveness in pericardium (p=0,045). They tended to have more common infradiaphragmatic involvement, less often tumor sclerosis or fluidothorax. There were no immunohistochemical differences between genetically confirmed and unconfirmed PMBLs. New approach of distinguishing PMBL and DLBCL is presented. It is based on expression of three genes in routinely available FFPE material using RTqPCR.

[Angiogenesis as part of the tumor "ecosystem" and possibilities to influence it]. / Angiogeneze jako soucást nádorového "ekosystému" a moznosti jejího ovlivnení.

Angiogenesis is a complex process which is critical for the growth, invasion and metastasis of tumors. In the past ten years numerous new agents have been developed as angiogenesis inhibitors. In the review, angiogenesis inhibitors are classified by their targeted area of the angiogenic process. The role of VEGF and its receptors is described in detail, but other antiangiogenic strategies such as inhibition of endothelial proliferation, inhibition of matrix metalloproteinases and use of vascular disrupting agents are also reviewed.

[ABL1, SRC and other non-receptor protein tyrosine kinases as new targets for specific anticancer therapy]. / ABL1, SRC a dalSí nereceptorové tyrozinkinázy jako nové cíle specifické protinádorové lécby.

Non-receptor protein tyrosine kinases are responsible for signal transduction during many physiologic cellular processes, including cell growth and proliferation, apoptosis, differentiation, regulation of actin cytoskeleton, cell shape, adhesion, motility and migration. Aberrant activity of protein tyrosine kinases (acquired as a result of chromosomal translocation or point mutation) has been implicated in the stimulation of cancer growth and progression, the induction of drug-resistance, tumour neovascularization, tissue invasion, extravasation and the formation of metastases. Small molecule tyrosine kinase inhibitors interfere with these pathophysiological circuits by blocking the signalling cascades triggered by the aberrantly activated protein tyrosine kinases (e.g. BCR-ABL1, FIP1L1-PDGFRA or ETV6-PDGFRB).Tyrosine kinase inhibitors (imatinib, nilotinib, dasatinib) now belong to established anti-cancer agents with clinical activity in patients with CML, Ph+ ALL, and myeloid neoplasms with overexpression of PDGFRA, PDGFRB and wild-type KIT. New generation tyrosine kinase inhibitors (e.g. dasatinib) with extended activity against SRC and EPH kinases belong to promising anti-cancer agents with documented preclinical activity in several solid tumours (e.g. prostate cancer).

Dendritic cells and T lymphocyte interactions in patients with lymphoid malignancies.

Dendritic cell (DC) vaccination is an attractive approach to the treatment of patients with lymphoid tumors. To evaluate its feasibility, we have tested the functional properties of DC and T-lymphocytes in patients with treated and untreated chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL). Healthy volunteers were used both as controls and as a source of cells for allogeneic mixed leukocyte reaction (MLR). In these reactions, dendritic cells from both untreated and treated patients were comparable to dendritic cells from healthy volunteers. In all the untreated patients studied, autologous dendritic cells promoted the survival and proliferation of both CD4 and CD8 lymphocytes (though the proliferation response was much better in the CD4 subset), whereas only 3 out of 5 treated patients were able to mount this response with CD4 lymphocytes and 4 out of 5 with CD8 lymphocytes. In 3 out of 5 untreated patients, pulsing of DCs with tetanus toxoid promoted a better CD4 response than was achieved with unpulsed DCs, while none of 5 treated patients had an additional response after pulsing with tetanus toxoid. None of patients studied, either treated or untreated, had a better CD8 response to pulsed DCs than to unpulsed ones. During CD4 lymphocyte proliferation, more CD4(+)CD25(hi) lymphocytes were generated in both treated and untreated patients than in healthy controls. Poor proliferation of cytotoxic cells and preferential proliferation of CD4(+)CD25(hi) T-regulatory cells in response to self and/or foreign antigens might be one of the mechanisms responsible for immunosuppression and impaired tumor surveillance in patients with lymphoid malignancies.