Maintenance therapy with ex vivo expanded lymphokine-activated killer cells and rituximab in patients with follicular lymphoma is safe and may delay disease progression.

Anti-cluster of differentiation 20 (CD20) monoclonal antibodies (mAbs) have shown promise in follicular lymphoma (FL) as post-induction therapy, by enhancing antibody-dependent cellular cytotoxicity (ADCC). However, cytotoxic cells are reduced after this treatment. We hypothesised that ex vivo expanded lymphokine-activated killer (LAK) cells administered to FL-remission patients are safe and improve anti-CD20 efficacy. This open, prospective, phase II, single-arm study assessed safety and efficacy of ex vivo expanded LAK cells in 20 FL-remission patients following rituximab maintenance. Mononuclear cells were obtained in odd rituximab cycles and stimulated with interleukin 2 (IL-2) for 8 weeks, after which >5 × 108 LAK cells were injected. Patients were followed-up for 5 years. At the end of maintenance, peripheral blood cells phenotype had not changed markedly. Natural killer, LAK and ADCC activities of mononuclear cells increased significantly after recombinant human IL-2 (rhIL-2) stimulation in all cycles. Rituximab significantly enhanced cytotoxic activity. No patients discontinued treatment. There were no treatment-related serious adverse events. Three patients had progressed by the end of follow-up. After a median (interquartile range) follow-up of 59.4 (43.8-70.9) months, 85% of patients remained progression free. No deaths occurred. Quality-of-life improved throughout the study. Post-induction LAK cells with rituximab seem safe in the long term. Larger studies are warranted to confirm efficacy.

Safety of switching from intravenous to subcutaneous rituximab during first-line treatment of patients with non-Hodgkin lymphoma: the Spanish population of the MabRella study.

Rituximab is a standard treatment for non-Hodgkin diffuse large B-cell (DLBCL) and follicular (FL) lymphomas. A subcutaneous formulation was developed to improve the resource use of intravenous rituximab, with comparable efficacy and safety profiles except for increased administration-related reactions (ARRs). MabRella was a phase IIIb trial to assess the safety of switching from intravenous to subcutaneous administration of rituximab during first-line induction/maintenance for DLBCL or FL, focusing on ARRs. Efficacy, satisfaction and quality of life were also assessed. Patients received subcutaneous rituximab plus standard induction chemotherapy for DLBCL or FL for 4-7 cycles, and/or every 2 months maintenance monotherapy for FL for 6-12 cycles. The study included 140 patients: DLBCL, n = 29; FL, n = 111. Ninety-five percent of patients experienced adverse events, reaching grade ≥3 in 38·6% and were serious in 30·0%. AARs occurred in 48·6%, mostly (84·9%) at the injection site, with only 2·1% of patients reaching grade 3. The end-of-induction complete/unconfirmed complete response rate was 69·6%. After a median follow-up of 33·5 months, median disease-/event-/progression-free and overall survivals were not attained. The Rituximab Administration Satisfaction Questionnaire showed improvements in overall satisfaction and the EuroQoL-5D a good quality-of-life perception at induction/maintenance end. Therefore, switching to subcutaneous rituximab showed no new safety issues and maintained efficacy with improved satisfaction and quality of life.

Richter transformation driven by Epstein-Barr virus reactivation during therapy-related immunosuppression in chronic lymphocytic leukaemia.

The increased risk of Richter transformation (RT) in patients with chronic lymphocytic leukaemia (CLL) due to Epstein-Barr virus (EBV) reactivation during immunosuppressive therapy with fludarabine other targeted agents remains controversial. Among 31 RT cases classified as diffuse large B-cell lymphoma (DLBCL), seven (23%) showed EBV expression. In contrast to EBV- tumours, EBV+ DLBCLs derived predominantly from IGVH-hypermutated CLL, and they also showed CLL-unrelated IGVH sequences more frequently. Intriguingly, despite having different cellular origins, clonally related and unrelated EBV+ DLBCLs shared a previous history of immunosuppressive chemo-immunotherapy, a non-germinal centre DLBCL phenotype, EBV latency programme type II or III, and very short survival. These data suggested that EBV reactivation during therapy-related immunosuppression can transform either CLL cells or non-tumoural B lymphocytes into EBV+ DLBCL. To investigate this hypothesis, xenogeneic transplantation of blood cells from 31 patients with CLL and monoclonal B-cell lymphocytosis (MBL) was performed in Rag2-/- IL2γc-/- mice. Remarkably, the recipients' impaired immunosurveillance favoured the spontaneous outgrowth of EBV+ B-cell clones from 95% of CLL and 64% of MBL patients samples, but not from healthy donors. Eventually, these cells generated monoclonal tumours (mostly CLL-unrelated but also CLL-related), recapitulating the principal features of EBV+ DLBCL in patients. Accordingly, clonally related and unrelated EBV+ DLBCL xenografts showed indistinguishable cellular, virological and molecular features, and synergistically responded to combined inhibition of EBV replication with ganciclovir and B-cell receptor signalling with ibrutinib in vivo. Our study underscores the risk of RT driven by EBV in CLL patients receiving immunosuppressive therapies, and provides the scientific rationale for testing ganciclovir and ibrutinib in EBV+ DLBCL. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

First-line use of rituximab correlates with increased overall survival in late post-transplant lymphoproliferative disorders: retrospective, single-centre study.

This retrospective study evaluates the impact of rituximab on PTLD response and survival in a single-centre cohort. PTLD cases between 1984 and 2009, including heart, kidney, liver and lung transplant recipients, were included. Survival was analysed taking into account the type of PTLD (monomorphic vs. polymorphic), EBV infection status, IPI score, Ann Arbor stage and use of rituximab. Among 1335 transplanted patients, 24 developed PTLD. Median age was 54 yr (range 29-69), median time to diagnosis 50 months (range 0-100). PTLD type was predominantly late/monomorphic (79% and 75%), mostly diffuse large B-cell type. Overall response rate (ORR) was 62% (66% rituximab vs. 50% non-rituximab; P = 0.5). R-CHOP-like regimens were used most frequently (72% of patients treated with rituximab). Median overall survival was 64 months (CI 95% 31-96). OS was significantly increased in patients treated with rituximab (P = 0.01; CI 95% rituximab 58-79 months; non-rituximab 1-30 months). Post-transplant immunosuppression regimen had no effect on survival or time to PTLD, except for cyclosporine A (CyA), which associated with increased time to PTLD (P = 0.02). Rituximab was associated with increased survival in our single-centre series, and it should be considered as first-line therapy for PTLD patients. The possible protective effect of CyA for development of PTLD should be prospectively evaluated.

The top ten clues to understand the origin of chronic lymphocytic leukemia (CLL).

The fundamental task of the immune system is to protect the individual from infectious organisms without serious injury to self. The essence of acquired immunity is molecular self/non self discrimination. Chronic lymphocytic leukemia is characterized by a global failure of immune system that begins with the failure of immunological tolerance mechanisms (autoimmunity) and finish with the incapacity to response to non-self antigens (immunodeficiency). Immunological tolerance mechanisms are involved in chronic lymphocytic leukemia (CLL) development. During B cell development some self-reactive B cells acquire a special BCR that recognize their own BCR. This self-autoantibody-self BCR interaction promotes survival, differentiation and proliferation of self-reactive B cells. Continuous self-autoantibody-self BCR interaction cross-linking induces an increased rate of surface BCR elimination, CD5+ expression, receptor editing and anergy. Unfortunately, some times this mechanisms increase genomic instability and promote additional genetic damage that immortalize self-reactive B cells and convert them into CLL like clones with the capability of clonal evolution and transformed CLL B cells. This review summarizes the immunological effects of continuous self-autoantibody-self BCR interaction cross-linking in the surface of self-reactive B cells and their role in CLL development.

Chronic lymphocytic leukaemia: could immunological tolerance mechanisms be the origin of lymphoid neoplasms?

Immunological tolerance theory in chronic lymphocytic leukaemia (CLL): we suggest that B cells that express B-cell receptors (BCR) that recognize their own BCR epitopes are viewed by immune system as 'dangerous cells'. BCR autonomous signalling may induce constant receptor editing and mistakes in allelic exclusion. The fact that whole BCR recognizes a self-antigen or foreing antigen may be irrelevant in early B cell development. In early B cells, autonomous signalling induced by recognition of the BCR's own epitopes simulates an antigen-antibody engagement. In the bone marrow this interaction is viewed as recognition of self-molecules and induces receptor editing. In mature B cells autonomous signalling by the BCR may promote 'reversible anergy' and also may correct self-reactivity induced by the somatic hypermutation mechanisms in mutated CLL B cells. However, in unmutated CLL B cells, BCR autonomous signalling in addition to self-antigen recognition augments B cell activation, proliferation and genomic instability. We suggest that CLL originates from a coordinated normal immunologic tolerance mechanism to destroy self-reactive B cells. Additional genetic damage induced by tolerance mechanisms may immortalize self-reactive B cells and transform them into a leukemia.

Lymphocyte recovery is impaired in patients with chronic lymphocytic leukemia and indolent non-Hodgkin lymphomas treated with bendamustine plus rituximab.

The immune system has the potential to either attenuate tumor growth or to promote tumor progression. The goal of cancer immunotherapy is to shift the balance in favor of tumor immunosurveillance, so that the immune system can recognize the tumor, eliminate it, and prevent its recurrence. Bendamustine plus rituximab is generally considered effective and safe in patients with previously untreated chronic lymphocytic leukemia (CLL) and indolent non-Hodgkin lymphomas. To evaluate the effects of bendamustine-rituximab and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) on the recuperation of immune system, we analyze the distribution of CD4+ and CD8+ T cells, B cells, and NK cells in peripheral blood of 18 patients who received 4-6 cycles of rituximab-bendamustine (BR) or six R-CHOP before therapy and 6 months after completing treatment. Our results indicate that lymphocyte recovery is impaired in patients with chronic lymphocytic leukemia and indolent lymphomas treated with bendamustine plus rituximab. Low CD4 T cells (<200 cells/µl) induced by bendamustine (BR) suggest prophylaxis should be applied against opportunistic infections. Asymptomatic EBV and CMV reactivations support a negative effect of BR on the immune system. If cellular immune therapy such as lymphokine-activated killer (LAK) or effector lymphocytes infusion is planned, regimes other than BR should be the first choice.

Immunological aspects in chronic lymphocytic leukemia (CLL) development.

Chronic lymphocytic leukemia (CLL) is unique among B cell malignancies in that the malignant clones can be featured either somatically mutated or unmutated IGVH genes. CLL cells that express unmutated immunoglobulin variable domains likely underwent final development prior to their entry into the germinal center, whereas those that express mutated variable domains likely transited through the germinal center and then underwent final development. Regardless, the cellular origin of CLL remains unknown. The aim of this review is to summarize immunological aspects involved in this process and to provide insights about the complex biology and pathogenesis of this disease. We propose a mechanistic hypothesis to explain the origin of B-CLL clones into our current picture of normal B cell development. In particular, we suggest that unmutated CLL arises from normal B cells with self-reactivity for apoptotic bodies that have undergone receptor editing, CD5 expression, and anergic processes in the bone marrow. Similarly, mutated CLL would arise from cells that, while acquiring self-reactivity for autoantigens-including apoptotic bodies-in germinal centers, are also still subject to tolerization mechanisms, including receptor editing and anergy. We believe that CLL is a proliferation of B lymphocytes selected during clonal expansion through multiple encounters with (auto)antigens, despite the fact that they differ in their state of activation and maturation. Autoantigens and microbial pathogens activate BCR signaling and promote tolerogenic mechanisms such as receptor editing/revision, anergy, CD5+ expression, and somatic hypermutation in CLL B cells. The result of these tolerogenic mechanisms is the survival of CLL B cell clones with similar surface markers and homogeneous gene expression signatures. We suggest that both immunophenotypic surface markers and homogenous gene expression might represent the evidence of several attempts to re-educate self-reactive B cells.

Serology-based therapeutic strategy in SARS-CoV-2-infected patients.

SARS-CoV-2 infection can be a life-threatening disease. The optimal treatment of patients is not yet standardized. We use a serology-based therapeutic strategy based on the presence of antibodies against the SARS-CoV-2 virus, in which patients with positive serology receive aggressive anti-inflammatory treatment with high-dose dexamethasone and/or tocilizumab and patients with negative serology receive early convalescent plasma therapy. We also analyze the immunological impact of this therapy in the recovery of T cells, B cells and NK cells during hospitalization in a COVID-19 infectious ward. Our results suggest that aggressive therapy with early administration of convalescent plasma and high-dose dexamethasone may be of benefit in patients with SARS-CoV-2 infection and might avoid progression of lung damage or need of admission in intensive care. This strategy did not impair immune responses against SARS-CoV-2, as 93% of the patients generated antibodies against the virus. Independently of previous immunological status of the patients, serology-guided therapy might benefit even patients with a high CIRS-G score, immunosuppressed or medically debilitated individuals and elderly patients. T cell disturbances were most frequent in patients who required high-dose dexamethasone, and B cell depletion was most frequent in patients who received tocilizumab. Early passive immunotherapy with convalescent plasma does not affect lymphoid recovery.

Real-World Characteristics and Outcome of Patients Treated With Single-Agent Ibrutinib for Chronic Lymphocytic Leukemia in Spain (IBRORS-LLC Study).

BACKGROUND: Ibrutinib demonstrated remarkable efficacy and favorable tolerability in patients with untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including those with high-risk genetic alterations. The IBRORS-CLL study assessed the characteristics, clinical management and outcome of CLL patients receiving ibrutinib in routine clinical practice in Spain. PATIENTS: Observational, retrospective, multicenter study in CLL patients who started single-agent ibrutinib as first-line treatment or at first or second relapse between January 2016 and January 2019. RESULTS: A total of 269 patients were included (median age: 70.9 years; cardiovascular comorbidity: 55.4%, including hypertension [47.6%] and atrial fibrillation [AF] [7.1%]). Overall, 96.7% and 69% of patients underwent molecular testing for del(17p)/TP53 mutation and IGHV mutation status. High-risk genetic features included unmutated IGHV (79%) and del(17p)/TP53 mutation (first-line: 66.3%; second-line: 23.1%). Overall, 84 (31.2%) patients received ibrutinib as first-line treatment, and it was used as second- and third-line therapy in 121 (45.0%) and 64 (23.8%) patients. The median progression-free survival and overall survival were not reached irrespective of del(17p)/TP53, or unmutated IGHV. Common grade ≥3 adverse events were infections (12.2%) and bleeding (3%). Grade ≥3 AF occurred in 1.5% of patients. CONCLUSION: This real-world study shows that single-agent ibrutinib is an effective therapy for CLL, regardless of age and high-risk molecular features, consistent with clinical trials. Additionally, single-agent ibrutinib was well tolerated, with a low rate of cardiovascular events. This study also emphasized a high molecular testing rate of del(17p)/TP53 mutation and IGHV mutation status in clinical practice according to guideline recommendations.

Full donor chimerism without graft-versus-host disease: the key factor for maximum benefit of pre-emptive donor lymphocyte infusions (pDLI).

Compared to standard-conditioned regimens, reduced-intensity conditioning and T-cell depletion deliver lower transplant-related mortality and decreased graft-vs-host disease after allogeneic hematopoietic stem-cell transplantation. These advantages may however be mitigated by increased relapse rates and delays in achievement of full donor chimerism (FDC). Pre-emptive donor lymphocyte infusions (pDLI) facilitate the conversion of mixed (MDC) to FDC. However, there is a lack of published data on the risk/benefit analysis of this intervention. We performed a retrospective analysis of 119 patients who received 276 pDLI doses for falling CD3 chimerism, CD3 < 50% or mixed XX/XY karyotype. 71/119(60%) Patients achieved FDC, with only one reverting to MDC. Cumulative incidence (CI) of relapse at 5 years was significantly lower in the FDC group (16.0 vs 41.4%, p < 0.001). Those patients who achieved FDC had improved EFS (p < 0.001) and OS (p < 0.001). Interestingly, patients with FDC who developed DLI-induced graft-vs-host disease (GvHD) showed a similar outcome to those with MDC. The majority of patients who receive pDLI convert to FDC and retain that status. Achievement of FDC after pDLI impacts on survival, and those patients who achieve FDC without GvHD, experience maximum clinical benefit. Strategies to minimise DLI-induced GvHD should be considered to maximise the therapeutic potential of this intervention.

Battle of Thermopylae: 300 Spartans (natural killer cells plus obinutuzumab) versus the immortal warriors (chronic lymphocytic leukemia cells) of Xerxes' army.

AIM: To analyze the effects of subcutaneous or intravenous rituximab + lymphokine-activated killer cells, obinutuzumab or ibrutinib on natural killer (NK) cell levels in chronic lymphocytic leukemia and follicular lymphoma patients. PATIENTS & METHODS: The distribution of peripheral blood NK cells of 31 patients was analyzed by flow cytometry. RESULTS: We detected a decrease of NK cells in peripheral blood below normal range after obinutuzumab treatment. During maintenance treatment with subcutaneous rituximab, an NK cell reduction was less pronounced than after intravenous rituximab treatment, despite lymphokine-activated killer cell infusions. CONCLUSION: After one dose of obinutuzumab, each NK cell in peripheral blood destroys 25 leukemic cells.

Obinutuzumab induces depletion of NK cells in patients with chronic lymphocytic leukemia.

AIM: Obinutuzumab induces NK cell antibody-dependent cell-mediated cytotoxicity. OBJECTIVE: Investigate the effects on the human immune system after obinutuzumab monotherapy treatment in patients with chronic lymphocytic leukemia (CLL). METHOD: To evaluate these effects, we analyzed the distribution of CD4+ and CD8+ T cells, B cells and NK cells in the peripheral blood of eight CLL patients who were treated with obinutuzumab in monotherapy. The distribution of peripheral blood lymphocytes was examined prior to each dose of obinutuzumab and 24-72 h after the first 1000 mg complete dose (cycle 1 day 2). We also repeated measurements 3 months after the last obinutuzumab dose. In total we obtained ten samples of each patient. Analyses were performed by flow cytometry with monoclonal antibodies against CD3, CD4, CD8, CD19 and CD56+. RESULTS: After the first 1000 mg obinutuzumab infusion (cycle 1 day 2), CD4+ T cells and CD8+ T cells were significantly decreased in peripheral blood compared with prior to therapy. This reduction in the CD4+ T cells persisted after six cycles of obinutuzumab (1235 cells/µl basal vs 662 cells/µl after six cycles, p ≤ 0.05), but not in CD8+ T cells (987 cells/µl basal vs 837 cells/µl after six cycles). Interestingly, we also observed significant differences in the NK cell compartment after the first 1000 mg drug infusion (490 cells/µl basal vs 23 cells/µl postinfusion, p ≤ 0.05), and after cycle 6 (490 cells/µl basal vs 149 cells/µl after six cycles, p ≤ 0.05). CONCLUSION: Obinutuzumab induces depletion of NK cells in CLL.

Follicular lymphoma (FL): Immunological tolerance theory in FL.

The ultimate cause of follicular lymphoma (FL) remains unknown. Remarkably, almost nothing is known about immunological tolerance mechanisms that might contribute to FL development. Immunological tolerance mechanisms, like other stimuli, also induce persistent changes of B cell receptors that induce genetic instability and molecular aberrations promoting the development of a neoplasm. Using the same method as Burnet, we provide a new perspective taking advantage of the comparison of a normal linear B cell differentiation process and FL development within the framework of clonal selection theory. We propose that FL is a malignancy of cells that acquire both translocation t(14;18) and self-BCR, inducing them to proliferate and mature, resistant to negative selection. Additional genetic damage induced by non-apoptotic tolerance mechanisms, such as receptor editing, may transform a self-reactive B cell with t(14;18) into an FL. The result of tolerogenic mechanisms and genetic aberrations is the survival of FL B cell clones with similar markers and homogenous gene expression signatures despite the different stages of maturation at which the molecular damage occurs. To antagonize further growth advantage due to self-antigen recognition and chronic activation of tolerance mechanisms in the apoptosis-resistant background of FL B cells, inhibitors of BCR signaling may be promising therapeutic options.

Follicular lymphoma: in vitro effects of combining lymphokine-activated killer (LAK) cell-induced cytotoxicity and rituximab- and obinutuzumab-dependent cellular cytotoxicity (ADCC) activity.

Follicular lymphoma (FL) is a disease of paradoxes-incurable but with a long natural history. We hypothesized that a combination of lymphokine-activated killer (LAK) cells and monoclonal antibodies might provide a robust synergistic treatment and tested this hypothesis in a phase II clinical trial (NCT01329354). In this trial, in addition to R-CHOP, we alternated the administration of only rituximab with rituximab and autologous LAK cells that were expanded ex vivo. Our objective was to determine the in vitro capability of LAK cells generated from FL patients to produce cytotoxicity against tumor cell lines and to determine rituximab- and obinutuzumab-induced cytotoxicity via antibody-dependent cellular cytotoxicity (ADCC) activity. We analyzed the LAK cell-induced cytotoxicity and rituximab (R)- and obinutuzumab (GA101)-induced ADCC activity. We show that LAK cells generated from FL patients induce cytotoxicity against tumor cell lines. R and GA101 enhance cytolysis through ADCC activity of LAK cells. Impaired LAK cell cytotoxicity and ADCC activity were detected in 50 % of patients. Percentage of NK cells in LAK infusions were correlated with the R- and GA101-induced ADCC. Our results indicate that the combination of R or GA101 and LAK cells should be an option as frontline maintenance therapy in patients with FL.

Homeobox NKX2-3 promotes marginal-zone lymphomagenesis by activating B-cell receptor signalling and shaping lymphocyte dynamics.

NKX2 homeobox family proteins have a role in cancer development. Here we show that NKX2-3 is overexpressed in tumour cells from a subset of patients with marginal-zone lymphomas, but not with other B-cell malignancies. While Nkx2-3-deficient mice exhibit the absence of marginal-zone B cells, transgenic mice with expression of NKX2-3 in B cells show marginal-zone expansion that leads to the development of tumours, faithfully recapitulating the principal clinical and biological features of human marginal-zone lymphomas. NKX2-3 induces B-cell receptor signalling by phosphorylating Lyn/Syk kinases, which in turn activate multiple integrins (LFA-1, VLA-4), adhesion molecules (ICAM-1, MadCAM-1) and the chemokine receptor CXCR4. These molecules enhance migration, polarization and homing of B cells to splenic and extranodal tissues, eventually driving malignant transformation through triggering NF-κB and PI3K-AKT pathways. This study implicates oncogenic NKX2-3 in lymphomagenesis, and provides a valid experimental mouse model for studying the biology and therapy of human marginal-zone B-cell lymphomas.

Class I and class II MHC polymorphisms in Mexican patients with Behçet's disease.

Behçet's disease is a multi-system inflammatory disorder of unknown etiology. The disease is more prevalent in Eastern Mediterranean countries and Japan where there is a linkage to HLA-B51. Mexican Mestizos are suitable subjects for studying the role of ethnicity in the susceptibility to Behçet's disease. High-resolution HLA class I and class II typing was performed by polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) reverse dot blot and PCR-single-strand polymorphism in 32 patients with Behçet's disease and 99 healthy ethnically-matched controls. A significant increased frequency of HLA-B(*)44 (P = 0.02; OR = 2.78; CI 95% = 1.1-7.7), HLA-B(*)52 (P = 0.02; OR = 5.33; CI 95% = 1.07-29.1), and HLA-B(*)56 (P = 0.003; OR = 4.19; CI 95% = 3.37-5.21) as well as HLA-DRB1(*)01 and HLA-DRB1(*)13 (p = 0.007; OR = 3.36; CI 95% = 1.22-9.27) was found in Mexican patients with Behçet's disease when compared to controls. The low frequency of native markers in Mexican Mestizo patients with Behçet's disease suggests that genetic admixture between Eastern Mediterraneans and Orientals with Amerindians is a recent event that increased the risk of developing Behçet's disease in the Mexican population.