Successful long-term monotherapy with rituximab in a patient with chronic lymphocytic leukemia of the B-cell-lineage: a case report

<p>Abstract</p> <p>Introduction</p> <p>Treatment of chronic lymphocytic leukemia of the B-cell-lineage is strongly based upon clinical staging because of the heterogeneous clinical course of this disease.</p> <p>Case presentation</p> <p>We describe a 62-year-old patient with newly diagnosed chronic lymphocytic leukemia of the B-cell-lineage who did not respond to several chemotherapy regimens including chlorambucil, fludarabine and cyclophosphamide, developing a marked neutropenia and thrombocytopenia with life-threatening infections. Further chemotherapy appeared not feasible because of bone marrow toxicity. The patient was treated with 600 mg/m²rituximab weekly followed by eight courses of biweekly therapy and then by long-term maintenance therapy, achieving almost complete remission of the symptoms and disease control.</p> <p>Conclusion</p> <p>After resistance to standard chemotherapy with chlorambucil and fludarabine, a patient with chronic lymphocytic leukemia of the B-cell-lineage was successfully treated with rituximab.</p

CD20 and CD19 targeted vectors induce minimal activation of resting B lymphocytes

B lymphocytes are an important cell population of the immune system. However, until recently it was not possible to transduce resting B lymphocytes with retro- or lentiviral vectors, making them unsusceptible for genetic manipulations by these vectors. Lately, we demonstrated that lentiviral vectors pseudotyped with modified measles virus (MV) glycoproteins hemagglutinin, responsible for receptor recognition, and fusion protein were able to overcome this transduction block. They use either the natural MV receptors, CD46 and signaling lymphocyte activation molecule (SLAM), for cell entry (MV-LV) or the vector particles were further modified to selectively enter via the CD20 molecule, which is exclusively expressed on B lymphocytes (CD20-LV). It has been shown previously that transduction by MV-LV does not induce B lymphocyte activation. However, if this is also true for CD20-LV is still unknown. Here, we generated a vector specific for another B lymphocyte marker, CD19, and compared its ability to transduce resting B lymphocytes with CD20-LV. The vector (CD19ds-LV) was able to stably transduce unstimulated B lymphocytes, albeit with a reduced efficiency of about 10% compared to CD20-LV, which transduced about 30% of the cells. Since CD20 as well as CD19 are closely linked to the B lymphocyte activation pathway, we investigated if engagement of CD20 or CD19 molecules by the vector particles induces activating stimuli in resting B lymphocytes. Although, activation of B lymphocytes often involves calcium influx, we did not detect elevated calcium levels. However, the activation marker CD71 was substantially up-regulated upon CD20-LV transduction and most importantly, B lymphocytes transduced with CD20-LV or CD19ds-LV entered the G1b phase of cell cycle, whereas untransduced or MV-LV transduced B lymphocytes remained in G0. Hence, CD20 and CD19 targeting vectors induce activating stimuli in resting B lymphocytes, which most likely renders them susceptible for lentiviral vector transduction

Isolation of neoantigen-specific human T cell receptors from different human and murine repertoires

(1) Background: Mutation-specific T cell receptor (TCR)-based adoptive T cell therapy represents a truly tumor-specific immunotherapeutic strategy. However, isolating neoepitope-specific TCRs remains a challenge. (2) Methods: We investigated, side by side, different TCR repertoires-patients' peripheral lymphocytes (PBLs) and tumor-infiltrating lymphocytes (TILs), PBLs of healthy donors, and a humanized mouse model-to isolate neoepitope-specific TCRs against eight neoepitope candidates from a colon cancer and an ovarian cancer patient. Neoepitope candidates were used to stimulate T cells from different repertoires in vitro to generate neoepitope-specific T cells and isolate the specific TCRs. (3) Results: We isolated six TCRs from healthy donors, directed against four neoepitope candidates and one TCR from the murine T cell repertoire. Endogenous processing of one neoepitope, for which we isolated one TCR from both human and mouse-derived repertoires, could be shown. No neoepitope-specific TCR could be generated from the patients' own repertoire. (4) Conclusion: Our data indicate that successful isolation of neoepitope-specific TCRs depends on various factors such as the heathy donor's TCR repertoire or the presence of a tumor microenvironment allowing neoepitope-specific immune responses of the host. We show the advantage and feasibility of using healthy donor repertoires and humanized mouse TCR repertoires to generate mutation-specific TCRs with different specificities, especially in a setting when the availability of patient material is limited

Long-term in vitro expansion ensures increased yield of central memory T cells as perspective for manufacturing challenges

Adoptive T cell therapy (ATT) has revolutionized the treatment of cancer patients. A sufficient number of functional T cells is indispensable for ATT efficacy; however, several ATT dropouts have been reported due to T cell expansion failure or lack of T cell persistence in vivo. With the aim of providing ATT also to those patients experiencing insufficient T cell manufacturing via standard protocol, we evaluated if minimally manipulative prolongation of in vitro expansion (long-term (LT) >3 weeks with IL-7 and IL-15 cytokines) could result in enhanced T cell yield with preserved T cell functionality. The extended expansion resulted in a 39-fold increase of murine CD8(+) T central memory cells (Tcm). LT expanded CD8(+) and CD4(+) Tcm cells retained a gene expression profile related to Tcm and T memory stem cells (Tscm). In vivo transfer of LT expanded Tcm revealed persistence and anti-tumor capacity. We confirmed our in vitro findings on human T cells, on healthy donors and diffuse large B cell lymphoma patients, undergoing salvage therapy. Our study demonstrates the feasibility of an extended T cell expansion as a practicable alternative for patients with insufficient numbers of T cells after the standard manufacturing process thereby increasing ATT accessibility

Perfluorocarbon Particle Size Influences Magnetic Resonance Signal and Immunological Properties of Dendritic Cells

The development of cellular tracking by fluorine (19F) magnetic resonance imaging (MRI) has introduced a number of advantages for following immune cell therapies in vivo. These include improved signal selectivity and a possibility to correlate cells labeled with fluorine-rich particles with conventional anatomic proton (1H) imaging. While the optimization of the cellular labeling method is clearly important, the impact of labeling on cellular dynamics should be kept in mind. We show by 19F MR spectroscopy (MRS) that the efficiency in labeling cells of the murine immune system (dendritic cells) by perfluoro-15-crown-5-ether (PFCE) particles increases with increasing particle size (560>365>245>130 nm). Dendritic cells (DC) are professional antigen presenting cells and with respect to impact of PFCE particles on DC function, we observed that markers of maturation for these cells (CD80, CD86) were also significantly elevated following labeling with larger PFCE particles (560 nm). When labeled with these larger particles that also gave an optimal signal in MRS, DC presented whole antigen more robustly to CD8+ T cells than control cells. Our data suggest that increasing particle size is one important feature for optimizing cell labeling by PFCE particles, but may also present possible pitfalls such as alteration of the immunological status of these cells. Therefore depending on the clinical scenario in which the 19F-labeled cellular vaccines will be applied (cancer, autoimmune disease, transplantation), it will be interesting to monitor the fate of these cells in vivo in the relevant preclinical mouse models

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Influence of comorbidity, age and performance status on treatment efficacy and safety of cetuximab plus irinotecan in irinotecan-refractory elderly patients with metastatic colorectal cancer

BACKGROUND: We investigated the influence of comorbidity, Eastern Cooperative Oncology Group (ECOG) performance status and age on the efficacy and safety profile of cetuximab and irinotecan in elderly irinotecan-pretreated patients with mCRC. METHODS: 497 patients with mCRC were entered in the database of this non-interventional study (NIS). Comorbid conditions were recorded. RESULTS: A total of 247 and 250 patients aged 65years, respectively, with a median age of 66 y were documented; 78% of the patients showed a reduced ECOG status. Grade III/IV toxicities occurred in 18% of patients without any difference between age groups although older patients had more comorbidities with a higher Charlson Comorbidity Index (CCI) (p=0.002). Skin rash was strongly related to response (p=0.006). Age, line of therapy, ECOG, gender and CCI had no influence on response. The objective response rates were similar: 38.1% for age 65years (p=0.57). Progression-free survival (PFS) did not differ between patients 18-65years (6.0months) and patients >65years (6.2months; p=0.99). Only PS had a negative impact on PFS (hazard ratio (HR): 0,499; 95% confidence interval (CI) 0.34-0.72; p=0.002), whereas the presence of skin toxicity (grade>1) influenced PFS and response rate (RR) positively (HR: 2.04; 95% CI, 1.6-2.6; p<0.001). CONCLUSIONS: Only PS and age had a negative influence on PFS irrespective of CCI or age. There were no significant differences in response rate and safety profile for elderly patients when treated with cetuximab and irinotecan. Comorbidities and age had no influence on efficacy or toxicity

R-split-CHOP chemotherapy for elderly patients with diffuse large B-cell lymphoma

OBJECTIVES: Chemoimmunotherapy with cyclophosphamide, doxorubicin, vincristine, prednisolone and rituximab (R-CHOP) is the standard of care for patients with diffuse large B-cell lymphoma (DLBCL). However, management of elderly patients is challenging as critical comorbidities often account for increased number of treatment related complications. PATIENTS AND METHODS: In the past 8 years, we have treated elderly patients with a full-dose R-CHOP regimen by splitting the administration of cyclophosphamide and doxorubicin over two days (R-split-CHOP) to reduce peak plasma level. Here, we retrospectively analyzed the results of 30 patients with newly diagnosed DLBCL. RESULTS: The overall response rate was found to be 87%, the overall survival probability after 3 years was 60.6% (95% CI, 42.1%-79.0%), the progression-free survival probability 49.7% (95% CI, 30.4%-68.9%), respectively. Grade 3/4 infectious complications were reported in 30% of patients, yet no treatment-related deaths occurred. CONCLUSION: We suggest that R-split-CHOP could be a valuable option to safely administer full-dose intensity R-CHOP to elderly patients at risk of treatment-related complications