Eosinophilic pleocytosis in the cerebrospinal fluid following CAR-T cell therapy for CNS lymphoma: A case for warning?

INTRODUCTION

CAR-T cell therapy, emerging as an efficient treatment option for patients with secondary central nervous system (CNS) lymphoma, is frequently complicated with immune effector cell-associated neurotoxicity syndrome (ICANS).

CASE PRESENTATION

We report a case of a 64-year-old woman with transformed follicular lymphoma, developing high-grade ICANS with eosinophilic pleocytosis following third-line therapy with CAR-T cells (tisagenlecleucel). During bridging therapy, she declined neurologically and was diagnosed with secondary CNS lymphoma. She received methotrexate-cytarabine-thiotepa-rituximab regimen with clinical and radiological improvement. Post-CAR-T cell infusion she developed cytokine release syndrome grade II and ICANS grade III. Given the lack of response to steroids, anakinra was initiated with complete ICANS resolution. Cerebrospinal fluid (CSF) analysis, performed only on day +10 due to thrombocytopenia, revealed eosinophils, while infections were excluded.

CONCLUSION

This report emphasizes the importance of CSF analysis in individuals with CAR-T-related neurotoxicity for elucidating the role of specific immune cells in such complications.

In chronic lymphocytic leukemia, activation of the thrombopoietin receptor promotes T-cell inhibitory properties, contributing to immunosuppression

In chronic lymphocytic leukemia (CLL), the immune system is skewed towards a suppressive milieu. Levels of thrombopoietin (TPO), promoting cellular immune regulatory activity in immune thrombocytopenic purpura, were shown to be elevated in CLL patients. This study explored TPO as a potential immunomodulator, supporting CLL progression. We evaluated CLL cell-induced expression of TPO receptor (TPO-R) on T-cells and effects of its activation on T-cell responses. CLL cell involvement in TPO generation was also assessed. Baseline TPO-R expression on CD4 + T-cells was found to be higher in CLL patients than in healthy controls (HC). Exposure of HC-T-cells to B-cells, especially to CLL-B-cells stimulated with B-cell activating molecules, resulted in enhanced TPO-R expression on T-cells. CLL-T-cell stimulation with TPO reduced their proliferation and expanded the regulatory T-cell (Treg) population. At baseline, phosphorylation of STAT5, known to impact the Treg phenotype, was elevated in CLL-T-cells relative to those of HC. Exposure to TPO further enhanced STAT5 phosphorylation in CLL-T-cells, possibly driving the observed Treg expansion. The CLL immune milieu is involved in promotion of inhibitory features in T-cells through increased TPO-R levels and TPO-induced intracellular signaling. TPO and its signaling pathway could potentially support immunosuppression in CLL, and may emerge as novel therapeutic targets.

Third BNT162b2 mRNA SARS-CoV-2 Vaccine Dose Significantly Enhances Immunogenicity in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

COVID-19-related mortality among hematopoietic stem cell transplantation (HSCT) recipients in the pre-vaccine era ranged between 22 and 33%. The Pfizer/BioNTech BNT162b2 vaccine demonstrated significant immunogenicity and efficacy in the healthy population; however, its long-term effects on allogeneic HSCT recipients remained unclear. Our study longitudinally evaluated humoral and cellular responses to the BNT162b2 vaccine in adult allogeneic HSCT patients. A positive response was defined as antibody titers ≥ 150 AU/mL post-second vaccination. Among 77 included patients, 51 (66.2%) responded to vaccination. Response-associated factors were female gender, recent anti-CD20 therapy, and a longer interval between transplant and vaccination. Response rates reached 83.7% in patients vaccinated >12 months post-transplant. At 6 months post-second vaccination, antibody titers dropped, but were significantly increased with the booster dose. Moreover, 43% (6/14) of non-responders to the second vaccination acquired sufficient antibody titers after booster administration, resulting in an overall response rate of 79.5% for the entire cohort. The BNT162b2 vaccine was effective in allogeneic transplant recipients. Although antibody titers decreased with time, the third vaccination led to their significant elevation, with 93% of third-dose responders maintaining titers above 150 AU/mL at 3 months post-administration.

Compromised activity of natural killer cells in diffuse large b-cell lymphoma is related to lymphoma-induced modification of their surface receptor expression

While natural killer (NK) cells are essential players in detection and elimination of malignant cells, these surveillance properties can be compromised by cancer cells. Since NK cell education primarily occurs in the bone marrow and lymphoid tissue, this process might be particularly affected by their infiltration with lymphoma cells. This study aimed to explore functional properties of diffuse large B-cell lymphoma (DLBCL) patient NK cells, which could potentially promote tumour immune evasion and disease propagation.NK cells isolated from the peripheral blood (PB) of 26 DLBCL patients and 13 age-matched healthy controls (HC) were analysed. The cytotoxic CD56^dim subtype was the only one identified in patients. Compared to HC, patient cells demonstrated low levels of inhibitory CD158a/b along with decreased expression of activating NKG2D and CD161 and increased inhibitory NKG2A levels. Patient NK cell cytotoxic activity was impaired, as were their degranulation and inflammatory cytokine production, which partially recovered following non-receptor-dependant stimulation.The phenotypically skewed and restricted population of patient NK cells, along with their blunted cytotoxic and immune-regulatory activity, appear to be driven by exposure to lymphoma environment. These NK cell functional aberrations could support lymphoma immune evasion and should be considered in the era of cellular therapy.

Polatuzumab-based regimen or CAR T cell for patients with refractory/relapsed DLBCL-a matched cohort analysis

Polatuzumab (Pola)-based regimens and chimeric antigen receptor T (CAR T) cells provide superior outcome compared to conventional chemoimmunotherapy in patients with relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL). Choosing between these strategies remains controversial. The efficacy of CAR T versus Pola-rituximab(R) /Pola-bendamustine(B)-R in R/R DLBCL patients after failing ≥2 lines of treatment was compared in a retrospective, 'real-world' study. Propensity score matching, for age, lymphoma category (de-novo/transformed), number of prior lines, Eastern Cooperative Oncology Group performance status and lactate dehydrogenase level, was applied to control for differences in patients' characteristics. Response rate, progression-free survival (PFS) and overall survival (OS) were analyzed. A total of 82 patients, treated with CAR T (n=41) or Pola-based regimens (n=41), were included. No treatment-related deaths occurred with CAR T vs. 3 (7.3%) with Pola. The overall and complete response rates were 83% and 58% with CAR T vs. 66% and 44% with Pola-based-regimens (p=0.077 and p=0.18, respectively). At a median follow-up of 9 months (range 1-19.2) and 16 months (range 0.7-25.3) for the CAR T and Pola arm respectively, the median PFS has not been reached for CAR T vs. 5.6 months for Pola (95% CI 3.6-7.6, p=0.014). Median OS has not been reached for CAR T vs. 10.8 months (95% CI 2.2-19.4) for Pola (p=0.026). To conclude, in a real-world setting, treatment with CAR T achieved superior PFS and OS compared to Pola-based regimens in patients with R/R DLBCL.

Effective elimination of high-dose methotrexate by repeated hemodiafiltration and high-flux hemodialysis in patients with acute kidney injury

INTRODUCTION

Acute kidney injury (AKI) after high dose methotrexate (HD-MTX) is associated with delayed MTX-excretion and life-threatening toxicity. Glucapridase, the recommended therapy, is expensive and not always available.

CASE SERIES

We describe 3 cases (69, 67, 73 years) with diffuse large B-cell lymphoma who developed AKI and early-onset severely delayed MTX elimination after HD-MTX. MTX serum concentrations were 101 and 69 μmol/L at 24 h after administration in two patients and 34 μmol/L at 32 h in the third.

MANAGEMENT AND OUTCOME

Since glucarpidase was unavailable, we performed daily high-flux hemodialysis (HF-HD) or online hemodiafiltration (HDF) sessions (median duration, 6 h). The median serum MTX elimination half-life during HDF/HF-HD sessions was similar in all patients (median, 4.4 h; IQR, 3.8-5.3 h), but serum MTX concentrations rebounded after each dialysis by a median of 40% of the trough concentrations. The three patients underwent multiple dialysis sessions, until MTX serum concentrations remained sufficiently low to be neutralized by leucovorin. Only 1 patient developed severe pancytopenia, and renal function normalized in all patients after 3-6 weeks.

DISCUSSION

In conclusion, when glucarpidase is unavailable or delayed, early, repeated and prolonged HDF/HF-HD effectively enhance MTX elimination and prevent toxicity in patients with AKI and severely delayed MTX elimination after HD-MTX.

Humoral serologic response to the BNT162b2 vaccine is abrogated in lymphoma patients within the first 12 months following treatment with anti-CD2O antibodies

Patients with lymphoma, especially those treated with anti-CD20 monoclonal antibodies (MoAb), suffer high COVID-19-associated morbidity and mortality. The goal of this study was to assess the ability of lymphoma patients to generate a sufficient humoral response after two injections of BNT162b2 Pfizer vaccine and to identify factors impacting the response. Antibody titers were measured with the SARS-CoV-2 IgG II Quant (Abbott©) assay in blood samples drawn from lymphoma patients 4±2 weeks after the 2nd vaccine dose. The cutoff for a positive response was set at 50AU/ml. Positive serological responses were observed in 51% of the 162 patients enrolled in this cross-sectional study. In a multivariate analysis, an interval of.

Single agent oral selinexor as a key to potential cure in refractory diffuse large B-cell lymphoma: case report and literature review

Relapsed/refractory diffuse large B-cell lymphoma (DLBCL) portends a poor prognosis, with an estimated overall survival of less than 6 months. In the presented case, a female patient with DLBCL refractory to multiple lines of therapy, including chimeric antigen receptor T-cells, was treated with single-agent selinexor, achieving partial response following 5 months of treatment, which allowed the patient to proceed to potentially curative allogeneic stem cell transplantion. This approach enabled the patient, who would otherwise have been considered a candidate for palliative care, to achieve the most prolonged complete response since her first lymphoma-specific treatment. This outcome implies that early identification of relapsed/refractory patients who may benefit most from this drug - either as a single agent or in drug combinations - is imperative.

ERK Activity in Immature Leukemic Cells Drives Clonal Selection during Induction Therapy for Acute Myeloid Leukemia

Selection of resistant clones following intensive chemotherapy is a common obstacle for cure in many cancers, particularly in acute myeloid leukemia (AML). In AML, clone-specific sensitivity to chemotherapy varies even within the same patient. Multiple mutations and genetic aberrations are associated with clones surviving chemotherapy. The current study explored the role of activated signaling pathways in chemoresistance as a function of cell maturation, reflected by CD34 expression. In-vitro, Kasumi-1 leukemic cell line, sorted by CD34 expression, showed increased apoptosis only in the CD34⁻ subpopulation after exposure to cytosine arabinoside (Ara-C) or daunorubicin. The resistant CD34⁺ subset demonstrated higher expression of ERK1/2 and BCL-2 proteins than CD34⁻ cells. MEK1/2 inhibition elevated Ara-C ability to induce apoptosis in CD34⁺ cells, suggesting that MEK1/2-ERK1/2 is surviving signaling, which correlates to cell maturation levels and plays a role in chemoresistance. Deep sequencing of sorted CD34^+/− populations, both derived from the same patient samples, demonstrated various subclonal distribution of NPM1, DNMT3A and FLT3-ITD mutations. Interestingly, in these samples, p-ERK levels and apoptosis rates following chemotherapy exposure significantly differed between CD34^+/− populations. Hence, clones may be selected due to their ability to escape apoptosis rather than a direct effect of chemotherapy on a specific mutated clone.

Immune dysfunction complexity in chronic lymphocytic leukemia ‒ an issue to consider when designing novel therapeutic strategies

A complex interplay between chronic lymphocytic leukemia (CLL) cells and different constituents of the immune system generally results in immune tolerance. As targeted therapies are gaining a critical role in the therapeutic landscape of this disease, their impact on the already perturbed immune milieu needs to be considered. This review addresses the issues of basic immune dysfunction in CLL which is further complicated by the effects of a number of novel targeted therapies used for this malignancy. These new approaches may simultaneously facilitate both anti- and pro-cancer activity, potentially compromising the depth of response to therapy. Current evidence suggests that exploiting combination therapy could potentially overcome at least part of these deleterious effects, thereby prolonging response to treatment and helping to restore immune activity.

Superior outcome of patients with favorable-risk acute myeloid leukemia using consolidation with autologous stem cell transplantation

Autologous stem cell transplantation (ASCT), intensifying anti-leukemic effects without significant treatment-related mortality (TRM), is particularly appealing in AML with favorable genetic/molecular profile. This study retrospectively evaluated the outcomes of post-remission treatment in consecutive favorable-risk AML patients. Sixty-six patients were included: 32 had mutated NPM1/wild-type FLT-ITD, 16 had t(8:21) and 18 - inv(16). Forty patients received chemotherapy alone, 26 underwent ASCT upfront. In time-dependent analysis, the ASCT group demonstrated higher relapse-free (RFS) (p = .001) and overall survivals (OS) (p = .0007). The 1-year RFS and OS were 44.2% vs 88% and 71% vs 96% for chemotherapy and ASCT, respectively. The corresponding TRM was 4/40 (10.0%) and 0/26 (0%), with relapse rates of 70.0% and 19.2% (p = .0002). In multivariate analysis, ASCT was associated with superior OS and RFS. In conclusion, ASCT offers significantly superior RFS and OS in favorable-risk AML in first complete remission. These data support the recent resurgence of interest in ASCT for AML.

Chronic lymphocytic leukemia cells acquire regulatory B-cell properties in response to TLR9 and CD40 activation

Circulating chronic lymphocytic leukemia (CLL) cells share phenotypic features with certain subsets of regulatory B-cells (Bregs). The latter cells have been reported to negatively regulate immune cell responses, mostly by provision of IL-10. The purpose of the current study was to identify and delineate Breg properties of CLL cells. B-cells and T-cells were obtained from the peripheral blood of untreated CLL patients diagnosed according to the 2008 Guidelines of the International Workshop on Chronic Lymphocytic Leukemia. Co-culture assays were used to examine the ability of CLL cells to suppress autologous T-cell immune responses. IL-10 potency of CLL cells was assessed following stimulation with activators of the toll-like receptor 9 (TLR9) or CD40 and was correlated with the inhibitory activity of the cells. TLR9-activated CLL cells were found to increase the frequency of CD4+CD25hiFOXp3+ regulatory T-cells (Tregs) and to inhibit autologous CD4+ T-cell proliferation. This signaling cascade proved to control IL-10 generation in CLL cells, which in turn promoted the inhibition of T-cell proliferation by CLL cells. However, CD40 activation of CLL cells, while exhibiting a similar ability to augment Treg frequency, did not either affect IL-10 generation or T-cell proliferation. In conclusion, CLL cells demonstrate a unique clonal quality of adopting Breg properties which promote modulation of T-cell characteristics. TLR9 appears to be a potent activator of regulatory abilities in CLL cells, possibly contributing to preferential immune escape of TLR9-responsive cells.

Minimal residual disease surveillance in chronic lymphocytic leukemia by fluorescence-activated cell sorting

Achievement of complete response (CR) to therapy in chronic lymphocytic leukemia (CLL) has become a feasible goal, directly correlating with prolonged survival. It has been established that the classic definition of CR actually encompasses a variety of disease loads, and more sensitive multiparameter flow cytometry and polymerase chain reaction methods can detect the disease burden with a much higher sensitivity. Detection of malignant cells with a sensitivity of 1 tumor cell in 10,000 cells (10(-4)), using the abovementioned sophisticated techniques, is the current cutoff for minimal residual disease (MRD). Tumor burdens lower than 10(-4) are defined as MRD-negative. Several studies in CLL have determined the achievement of MRD negativity as an independent favorable prognostic factor, leading to prolonged disease-free and overall survival, regardless of the treatment protocol or the presence of other pre-existing prognostic indicators. Minimal residual disease evaluation using flow cytometry is a sensitive and applicable approach which is expected to become an integral part of future prospective trials in CLL designed to assess the role of MRD surveillance in treatment tailoring.