The Use of Infliximab to Control Recurrent Cytokine Storms in EBV-Associated Angioimmunoblastic Lymphoma and Hemophagocytic Syndrome

Introduction: Chronic active Epstein-Barr virus infection (CAEBV) has been implicated in several diseases including hemophagocytic lymphohistiocytosis (EBV-HLH) and lymphomas including Angioimmunoblastic T cell lymphoma. The exact mechanism by which EBV infection causes these complications is currently not well understood. EBV-HLH is a syndrome in which T-cells, NK cells and macrophages are aberrantly activated. Cytokine storms play a major role in cellular damage and organ dysfunction. In the event that the body is unable to clear the EBV viremia, dysregulated T, NK cells and macrophages continue to release cytokines leading to the accumulation of lymphohistiocytic infiltrates into organs and organ damage. Cytokine storms can lead to death from multi-organ failure. During a cytokine storm, levels of several cytokines are elevated including TNF-a, IFN-g, sCD25, IL-12, IL-1, IL-10 and IL-18.1–3 Current lines of therapy of EBV-HLH include steroids, etoposide, cyclosporine, ATG and hematopoietic stem cell transplantation. We report successfully controlling frequent cytokine storms in a patient with EBV induced angioimmunoblastic lymphoma and HLH with weekly infliximab after failure to do so with chemotherapy (CHOP-E; cyclophosphamide, daunorubicin, vincristine, prednisone, etoposide), rituximab and bortezomib

New interleukin-15 superagonist (IL-15SA) significantly enhances graft-versus-tumor activity.

Interleukin-15 (IL-15) is a potent cytokine that increases CD8+ T and NK cell numbers and function in experimental models. However, obstacles remain in using IL-15 therapeutically, specifically its low potency and short in vivo half-life. To help overcome this, a new IL-15 superagonist complex comprised of an IL-15N72D mutation and IL-15RαSu/Fc fusion (IL-15SA, also known as ALT-803) was developed. IL-15SA exhibits a significantly longer serum half-life and increased in vivo activity against various tumors. Herein, we evaluated the effects of IL-15SA in recipients of allogeneic hematopoietic stem cell transplantation. Weekly administration of IL-15SA to transplant recipients significantly increased the number of CD8+ T cells (specifically CD44+ memory/activated phenotype) and NK cells. Intracellular IFN-γ and TNF-α secretion by CD8+ T cells increased in the IL-15SA-treated group. IL-15SA also upregulated NKG2D expression on CD8+ T cells. Moreover, IL-15SA enhanced proliferation and cytokine secretion of adoptively transferred CFSE-labeled T cells in syngeneic and allogeneic models by specifically stimulating the slowly proliferative and nonproliferative cells into actively proliferating cells.We then evaluated IL-15SA\u27s effects on anti-tumor activity against murine mastocytoma (P815) and murine B cell lymphoma (A20). IL-15SA enhanced graft-versus-tumor (GVT) activity in these tumors following T cell infusion. Interestingly, IL-15 SA administration provided GVT activity against A20 lymphoma cells in the murine donor leukocyte infusion (DLI) model without increasing graft versus host disease. In conclusion, IL-15SA could be a highly potent T- cell lymphoid growth factor and novel immunotherapeutic agent to complement stem cell transplantation and adoptive immunotherapy

Extreme Peripheral Blood Plasmacytosis Mimicking Plasma Cell Leukemia as a Presenting Feature of Angioimmunoblastic T-Cell Lymphoma (AITL).

Angioimmunoblastic T-cell lymphoma (AITL) is one of four major subtypes of nodal peripheral T cell lymphoma, characterized by its cell of origin, the follicular helper T-cell (TFH). Patients typically present with prominent constitutional (B) symptoms, generalized lymphadenopathy, hepatosplenomegaly, cytopenias, and rash. Here we present a case of a 62-year-old male with progressive cervical adenopathy, fevers and weight loss presenting with extreme polyclonal plasmacytosis and high plasma EBV viral load. While the initial presentation appeared to mimic plasma cell leukemia or severe infection, lymph node biopsy and bone marrow biopsy confirmed a diagnosis of AITL. This case highlights the heterogeneity of the clinical presentation of AITL to enable physicians to more promptly recognize, diagnose and initiate treatment

Double Haploidentical Hematopoietic Stem Cell Transplantation Results in Successful Engraftment of Bone Marrow from Both Donors without Graft-versus-Host or Graft-versus-Graft Effects

We established double-haploidentical (DH) hematopoietic stem cell transplantation (HSCT) murine models to explore competitive engraftment, graft-versus-graft effect and graft-versus-host disease (GVHD). T cell–depleted (TCD) bone marrow (BM) cells from B6SJF1 (donor 1 [D1]) and B6D2F1 (donor 2 [D2]) mice achieved >90% donor engraftment when transplanted into B6CBAF1 mice. B6CBAF1 recipients survived without evidence of GVHD when undergoing HSCT with TCD-BM from 2 haploidentical donors, D1 and D2. DH-HSCT recipients had significantly higher leukocyte and neutrophil counts than single-haploidentical HSCT recipients from either D1 or D2. DH recipients consistently showed successful mixed chimerism in both BM and spleen. Two other DH-HSCT models, B6D2F1 + C3D2F1→B6C3F1 and B6CBAF1 + B6SJLF1→B6D2F1, showed similar engraftment patterns. Low-dose T cell infusion from both D1 and D2 increased the degree of early engraftment of the respective donors in BM and spleen; however, this early engraftment pattern did not determine long-term engraftment dominance. In the long term, minimally engrafted D1 BM recovered and comprised >50% of all donor- derived B, T, and natural killer cells. We conclude that early BM engraftment is determined by donor T cell immunodominance, but long-term engraftment is related to the engraftment potential of stem cells after DH-HSCT

Ocular surface epithelia contain ABCG2-dependent side population cells exhibiting features associated with stem cells.

When cell populations are incubated with the DNA-binding dye Hoechst 33342 and subjected to flow cytometry analysis for Hoechst 33342 emissions, active efflux of the dye by the ABCG2/BCRP1 transporter causes certain cells to appear as a segregated cohort, known as a side population (SP). Stem cells from several tissues have been shown to possess the SP phenotype. As the lack of specific surface markers has hindered the isolation and subsequent biochemical characterization of epithelial stem cells this study sought to determine the existence of SP cells and expression of ABCG2 in the epithelia of the ocular surface and evaluate whether such SP cells had features associated with epithelial stem cells. Human and rabbit limbal-corneal and conjunctival epithelial cells were incubated with Hoechst 33342, and analyzed and sorted by flow cytometry. Sorted cells were subjected to several tests to determine whether the isolated SP cells displayed features consistent with the stem cell phenotype. Side populations amounting to \u3c1% of total cells, which were sensitive to the ABCG2-inhibitor fumitremorgin C, were found in the conjunctival and limbal epithelia, but were absent from the stem cell-free corneal epithelium. Immunohistochemistry was used to establish the spatial expression pattern of ABCG2. The antigen was detected in clusters of conjunctival and limbal epithelia basal cells but was not present in the corneal epithelium. SP cells were characterized by extremely low light side scattering and contained a high percentage of cells that: showed slow cycling prior to tissue collection; exhibited an initial delay in proliferation after culturing; and displayed clonogenic capacity and resistance to phorbol-induced differentiation; all features that are consistent with a stem cell phenotype

A 2-Step Approach to Myeloablative Haploidentical Stem Cell Transplantation with Optimized T-Cell Dosing: Early Immune Reconstitution Leads to Better Outcomes

We developed a 2-step approach to myeloablative haploidentical HSCT in which patients receive a large fixed dose of cyclophosphamide (CY)-tolerized T cells separately frm the HSC infusion in the hopes of accelerating post HSCT immune reconstitution (IR). The uniformity of the T cell dosing facilitates comparison of patients without (low risk) and with (high risk) active malignancy at HSCT to ascertain the impact of disease status at HSCT on IR with fewer confounding effects from conditioning or T cell dosing

GITR Activation Induces an Opposite Effect on Alloreactive CD4+ and CD8+ T Cells in Graft-Versus-Host Disease

Glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) is a member of the tumor necrosis factor receptor (TNFR) family that is expressed at low levels on unstimulated T cells, B cells, and macrophages. Upon activation, CD4+ and CD8+ T cells up-regulate GITR expression, whereas immunoregulatory T cells constitutively express high levels of GITR. Here, we show that GITR may regulate alloreactive responses during graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). Using a BMT model with major histocompatibility complex class I and class II disparity, we demonstrate that GITR stimulation in vitro and in vivo enhances alloreactive CD8+CD25− T cell proliferation, whereas it decreases alloreactive CD4+CD25− proliferation. Allo-stimulated CD4+CD25− cells show increased apoptosis upon GITR stimulation that is dependent on the Fas–FasL pathway. Recipients of an allograft containing CD8+CD25− donor T cells had increased GVHD morbidity and mortality in the presence of GITR-activating antibody (Ab). Conversely, recipients of an allograft with CD4+CD25− T cells showed a significant decrease in GVHD when treated with a GITR-activating Ab. Our findings indicate that GITR has opposite effects on the regulation of alloreactive CD4+ and CD8+ T cells

High Local Control and Low Ocular Toxicity Using Ultra-Low-Dose “Boom-Boom” Radiotherapy for Indolent Orbital Lymphoma

Background: The first line definitive treatment for early-stage indolent B-cell lymphoma is radiation therapy (RT). Due to the sensitivity of orbital structures to radiation, ultra-low-dose RT (4 Gy in 2 fractions, boom-boom ) has and been utilized as an attractive option for orbital lymphoma. In this retrospective study, we evaluated the outcome and toxicity of boom-boom RT for indolent orbital lymphoma with an emphasis on ophthalmologic toxicity. Methods: This is a retrospective case series with 17 patients with orbital lymphoma who received boom-boom RT at a single tertiary referral center between January 2017 and June 2022. Medical records, imaging and radiation treatment plans were reviewed. Endpoints included response rate, progression, and ocular toxicity per oncologist and ophthalmology reports. Results: A total of 17 patients (12 female and 5 male) with 19 indolent orbital lymphomas were included. Median follow-up was 39 months. Complete, partial, and stable response was achieved in 65%, 24%, and 12% of patients, respectively. Only 1 patient developed local recurrent 47 month after radiation treatment, and was successfully salvaged with standard dose radiation (24 Gy). Five-year distant progression rate is 18%. Oncologist-reported Common Terminology Criteria for Adverse Events (CTCAE) toxicity rates were 6% grade 1 and 0% grade 2+. Ophthalmologist reported 33.3% new post-RT toxicities including dry eye, cataract, and chorioretinal atrophy. There is no significant vision acuity change after RT. Conclusions: Boom-Boom RT (4 Gy in 2 fractions) provides excellent control for indolent orbital lymphoma. While minimal toxicity was documented by radiation oncologists, higher rates were noted by ophthalmologists, highlighting the radiosensitivity of orbital structures and potentially underreported ocular toxicity in boom-boom and standard regimens. Further prospective randomized studies are needed to better define the outcome and toxicity of ultra-low-dose (4 Gy) RT for ocular lymphoma