Intrathecal donor lymphocyte infusion for isolated leukemia relapse in the central nervous system following allogeneic stem cell transplantation: a case report and literature review

Strategies for Altering Delivery Technologies to Optimize CAR Therapy

Chimeric antigen receptor (CAR) T-cell therapy has been proven to be an effective strategy for the treatment of hematological malignancies. At present, how to prepare CAR-T cells efficiently, quickly, and safely is one of the urgent problems to be solved. The durability and activity of engineered T cells in solid tumors need to be further improved, and the strategy of T cells penetrating the tumor microenvironment also needs to be improved. In addition, although the problems mainly caused by T-cell biology are being solved, the manufacturing mode and process still need to be improved to ensure that CAR-T cell therapy can be widely used. This paper summarizes some strategies that can improve the efficacy of CAR-T cells.

Diagnosis and management of adult central nervous system leukemia

Central nervous system leukemia (CNSL) is a prominent infiltration reason for therapy failing in acute leukemia. Recurrence rates and the prognosis have alleviated with current prophylactic regimens. However, the accurate stratification of relapse risk and treatment regimens for relapsed or refractory patients remain clinical challenges yet to be solved. Recently, with hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cellular therapy showing encouraging effects in some CNSL patients, advances in treating CNSL have already been reported. The development of molecular targeted agents as well as antibody-based drugs will provide patients with more personalized treatment. This article summarized recent research developments about risk factors, diagnosis, prevention, and treatment in adults with CNSL.

Prognostic factors for clinical outcomes of patients with central nervous system leukemia

Prognostic factors associated with clinical outcomes of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) patients with central nervous system (CNS) involvement are unknown. We retrospectively studied the characteristics and outcomes of 66 (18 pediatric and 48 adult) patients with CNS leukemia with ALL (n = 41) or AML (n = 25). The median age of patients at diagnosis of CNS leukemia was 30 (range, 1-69) years. Nearly two-third patients had CNS involvement at the initial diagnosis of leukemia. Complete remission of CNS leukemia was attained in 58 (88%) patients, and probability of overall survival at 36 months after the diagnosis of CNS leukemia was 43% for the entire cohort. We identified that achieving remission of systemic leukemia and having CNS leukemia diagnosed and treated before allogeneic transplantation were the factors associated with CNS leukemia remission. Prognostic factors associated with better overall survival in patients with CNS leukemia included pediatric age, diagnosis of CNS leukemia before receiving allogenic transplantation, achieving clearance of systemic or CNS leukemia, receiving no cranial radiation in conjunction with intrathecal chemotherapy (IT), and receiving IT consolidation after achieving remission of CNS leukemia. Our findings show that patients with CNS leukemia are at considerable risk of mortality. Awareness of modifiable prognostic factors such as avoidance of cranial radiation whenever possible and use of IT consolidation can result in improved outcomes in subset of patients with CNS leukemia.

Post-transplant leukemia relapse in organs: biology. and behavior in 585 reports

Resistance of extramedullary leukemia growth post-transplant prevents cure. Review of its behavior detailed in 585 published cases should lead to better treatment. Leukemic tumors were found up to 13 years after transplant, most in sites inaccessible to physical exam. In 83%, marrow was not in morphologic relapse; next relapse was most often extramedullary. Induction protocols alone produced few durable responses in acute leukemias and fatal marrow aplasia in 17 %. Overall, 120 patients survived over 2 years, 43 relapse-free up to 18 years, the majority after combined tumor-directed and systemic therapy. Overall median survival was 9 months. This review highlights how results can improve: by defining extent of leukemia involvement with scans before transplant, and emergently when leukemic tumor is found after, ablating tumor directly to abort metastasis, and determining dosing of systemic chemotherapy that protects, without ablating, donor marrow. Monitoring total body remission with body scans should increase transplant cures.

Very late recurrence of B-cell acute lymphoblastic leukemia masquerading as a pituitary tumor

Involvement of the pituitary gland by leukemic infiltration is exceedingly rare. Here, we describe a very late recurrence of B-cell acute lymphoblastic leukemia masquerading as a pituitary tumor and review the literature for previously reported cases. Our female patient presented 13 years after completion of therapy for B-ALL with headache, amenorrhea, galactorrhea and a pituitary mass. Subsequent studies revealed recurrence of her leukemia, and the pituitary lesion resolved after induction chemotherapy. Our case highlights the importance of considering leukemic infiltrate in the differential diagnosis of pituitary mass, particularly in a patient with a history of hematologic malignancy, sparing unnecessary surgical intervention and informing endocrine evaluation. In addition, the case also highlights difficulties with characterizing this recurrence as a very late relapse or clonal evolution of the original leukemia.

Successful application of anti-CD19 CAR-T therapy with IL-6 knocking down to patients with central nervous system B-cell acute lymphocytic leukemia

Few studies have described chimeric antigen receptor–modified T cell (CAR-T) therapy for central nervous system (CNS) B-cell acute lymphocytic leukemia (B-ALL) patients due to life-threatening CAR-T-related encephalopathy (CRES) safety issues. In this study, CAR-Ts targeting CD19 with short hairpin RNA (shRNA)-IL-6 gene silencing technology (ssCART-19s) were prepared. We conducted a phase 1 clinical trial (ClinicalTrials.gov number, NCT03064269). Three patients with relapsed CNS B-ALL were enrolled, conditioned with the fludarabine and cyclophosphamide for lymphocyte depletion and infused with ssCART-19s for three consecutive days. Clinical symptoms and laboratory examinations were monitored. After ssCART-19 treatment, three patients' symptoms resolved almost entirely. Brain leukemic infiltration reduced significantly based on magnetic resonance imaging (MRI), and there were no leukemic blasts in cerebrospinal fluid (CSF), which was confirmed by cytological and molecular examinations. Additionally, increases in the levels of cytokines and immune cells were observed in the CSF of all patients. Only grade 1 cytokine release syndrome (CRS) manifesting as fever was noted in patients. In conclusion, CAR-Ts with shRNA-IL-6 gene knockdown migrated into the CNS, eradicated leukemic cells and elevated cytokines in CSF with mild, acceptable side effects.

Direct Delivery of piggyBac CD19 CAR T Cells Has Potent Anti-tumor Activity against ALL Cells in CNS in a Xenograft Mouse Model

The anti-CD19 chimeric antigen receptor (CAR) T cells showed excellent effect against acute lymphoblastic leukemia (ALL) in bone marrow (BM) in clinical trials. However, it remains to be elucidated whether the CD19 CAR T cell therapy is effective for ALL cells in central nervous system (CNS) because the patients with isolated or advanced CNS disease were excluded from clinical trials of systemic intravenous (i.v.) delivery of CAR T cells. Therefore, the preclinical evaluation for the efficacy of CAR T cell therapy against ALL cells in CNS is essential for clinical application. We evaluated the effect and adverse reaction of CD19 CAR T cells against ALL in CNS using a xenograft mouse model by i.v. or intra-cerebroventricular (i.c.v.) delivery of CAR T cells. Injection of piggyBac CD19 CAR T cells by i.v. had partial effects, whereas all CAR T i.c.v.-delivered mice had eliminated ALL in CNS. Although some CAR T i.c.v.-delivered mice showed transient changes of clinical symptoms during the first few days after treatment, none of CAR T i.c.v.-delivered mice displayed fatal adverse events. In this study, we demonstrated that direct delivery into CNS of CAR T cells is a possible therapeutic approach with the xenograft mouse model.

Treatment of Epstein-Barr virus associated central nervous system diseases after allogeneic hematopoietic stem cell transplantation with intrathecal donor lymphocyte infusion

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective measure for the treatment of hematological disease. With the progress and widespread use of allo-HSCT, Epstein-Barr virus (EBV) related central nervous system (CNS) diseases have gotten more and more attention because of its poor prognosis and overall survival. Since currently there is no standard treatment for patients with EBV-associated CNS diseases and reported therapies are heterogeneous with mixed results, we attempted to develop a novel therapeutic method. We applied a regimen of intrathecal donor lymphocyte infusion (IDLI) in three patients with EBV-associated CNS diseases after allo-HSCT in addition to immunosuppressants reduction and combined antiviral therapy. All of three patients were responsive to this therapy: all clinical symptoms and EBV load in CSF were resolved 10, 17, and 12 days after initial IDLI, respectively, and magnetic resonance imaging (MRI) showed that lesions of case 1 and 2 disappeared 15 and 19 days after initial IDLI, respectively. Even more appealing, there were no acute or chronic adverse reactions during the infusion and up to 23 months of follow-up. In conclusion, IDLI seems to be an effective and safe method for EBV-associated CNS diseases in allo-HSCT recipients. We recommend this treatment modality for further investigation.

Genetically enhanced T lymphocytes and the intensive care unit

Chimeric antigen receptor-modified T cells (CAR-T cells) and donor lymphocyte infusion (DLI) are important protocols in lymphocyte engineering. CAR-T cells have emerged as a new modality for cancer immunotherapy due to their potential efficacy against hematological malignancies. These genetically modified receptors contain an antigen-binding moiety, a hinge region, a transmembrane domain, and an intracellular costimulatory domain resulting in lymphocyte T cell activation subsequent to antigen binding. In present-day medicine, four generations of CAR-T cells are described depending on the intracellular signaling domain number of T cell receptors. DLI represents a form of adoptive therapy used after hematopoietic stem cell transplant for its anti-tumor and anti-infectious properties. This article covers the current status of CAR-T cells and DLI research in the intensive care unit (ICU) patient, including the efficacy, toxicity, side effects and treatment.

Intrathecal Infusion of Haploidentical Nondonor Lymphocytes for Central Nervous System Leukemic Relapse After Haploidentical Hematopoietic Stem Cell Transplantation

Leukemic relapse in the central nervous system (CNS) after conventional treatment is associated with a poor prognosis. The effectiveness and safety of IV infusion of human leukocyte antigen (HLA)-mismatched lymphocytes for leukemia, and intrathecal (IT) infusion of HLA-mismatched lymphocytes for cerebrospinal fluid (CSF) dissemination of medulloblastoma have been reported. A 13-year-old girl (HLA-A31) was diagnosed as relapsing from Philadelphia chromosome-positive acute leukemia in the CNS after receiving chemotherapy, tyrosine kinase inhibitors, haploidentical hematopoietic stem cell transplantation (HSCT) from her father (HLA-A31), and craniospinal irradiation. We performed an IT infusion of haploidentical lymphocytes from her mother. Peripheral blood mononuclear cells obtained from her mother (HLA-A31) were administered by IT infusion weekly. Examination of CSF 1 week after first IT showed that lymphocyte counts had increased markedly and the breakpoint cluster region/abelson-bearing cells had disappeared. Furthermore, CD3 T cells in the CSF were negative for HLA-A31, and expressed high HLA-DR. These results indicate the infused non-HSCT-donor lymphocytes did not survive, and that the HSCT donor(father)-derived lymphocytes migrated to the CSF and were activated. The patient showed partial remission for 2 months following this therapy. Serious adverse reactions and graft versus host disease were not observed. To control leukemic CNS dissemination, haploidentical nondonor lymphocytes might contribute to a graft versus leukemia effect.