Managing leukapheresis in adult and pediatric patients eligible for chimeric antigen receptor T-cell therapy: suggestions from an Italian Expert Panel

Chimeric antigen receptor (CAR) T-cell therapy relies on T cells engineered to target specific tumor antigens such as CD-19 in B-cell malignancies. In this setting, the commercially available products have offered a potential long-term cure for both pediatric and adult patients. Yet manufacturing CAR T cells is a cumbersome, multistep process, the success of which strictly depends on the characteristics of the starting material, i.e., lymphocyte collection yield and composition. These, in turn, might be affected by patient factors such as age, performance status, comorbidities, and previous therapies. Ideally, CAR T-cell therapies are a one-off treatment; therefore, optimization and the possible standardization of the leukapheresis procedure is critical, also in view of the novel CAR T cells currently under investigation for hematological malignancies and solid tumors. The most recent Best Practice recommendations for the management of children and adults undergoing CAR T-cell therapy provide a comprehensive guide to their use. However, their application in local practice is not straightforward and some grey areas remain. An Italian Expert Panel of apheresis specialists and hematologists from the centers authorized to administer CAR T-cell therapy took part in a detailed discussion on the following: 1) pre-apheresis patient evaluation; 2) management of the leukapheresis procedure, also in special situations represented by low lymphocyte count, peripheral blastosis, pediatric population <25 kg, and the COVID-19 outbreak; and 3) release and cryopreservation of the apheresis unit. This article presents some of the important challenges that must be faced to optimize the leukapheresis procedure and offers suggestions as to how to improve it, some of which are specific to the Italian setting.

Biological quality control for extracorporeal photochemotherapy: Assessing mononuclear cell apoptosis levels in ECP bags of chronic GvHD patients

Extracorporeal photochemotherapy (ECP) is a treatment approved by the FDA for cutaneous T-cell lymphoma, and it is currently used off-label for graft-versus-host disease (GvHD) and other conditions. In agreement with good practices for the therapeutic use of human cells, quality control has to be performed to validate the ECP procedure with the off-line technique. Since no gold-standard biological test is available, we assessed the apoptosis generated in the ECP bag using a flow cytometric analysis. Thirty-one ECP procedures performed on 13 patients with chronic GvHD were studied by monitoring the induction of mononuclear cell (MNC) apoptosis using annexin V/propidium iodide double staining; residual lymphocyte proliferation to standard mitogens was also measured in 17 of the procedures. The kinetics of apoptosis was analyzed at different times in MNCs untreated or treated with 8-methoxy-psoralen plus ultraviolet A; the variation (ΔAPOPTOSIS ) after 24 h revealed the efficacy of the treatment. In 88.6% of the 31 ECP procedures, ΔAPOPTOSIS was >15% (the "alerting" threshold for ΔAPOPTOSIS was set at 15% on the basis of our data); in the remainder (19.4%), the increment in apoptosis was lower. In four procedures, the proliferation assay was useful for assessing the effect of ECP on the apheretic bag. In conclusion, both flow cytometric assays enabled a biologically significant result to be obtained. In our opinion, the apoptosis test-being faster and easier than the proliferation test-could be a reliable way to validate ECP procedures.

Stearoyl-CoA desaturase-1 is a key factor for lung cancer-initiating cells

In recent years, studies of cancer development and recurrence have been influenced by the cancer stem cells (CSCs)/cancer-initiating cells (CICs) hypothesis. According to this, cancer is sustained by highly positioned, chemoresistant cells with extensive capacity of self renewal, which are responsible for disease relapse after chemotherapy. Growth of cancer cells as three-dimensional non-adherent spheroids is regarded as a useful methodology to enrich for cells endowed with CSC-like features. We have recently reported that cell cultures derived from malignant pleural effusions (MPEs) of patients affected by adenocarcinoma of the lung are able to efficiently form spheroids in non-adherent conditions supplemented with growth factors. By expression profiling, we were able to identify a set of genes whose expression is significantly upregulated in lung tumor spheroids versus adherent cultures. One of the most strongly upregulated gene was stearoyl-CoA desaturase (SCD1), the main enzyme responsible for the conversion of saturated into monounsaturated fatty acids. In the present study, we show both by RNA interference and through the use of a small molecule inhibitor that SCD1 is required for lung cancer spheroids propagation both in stable cell lines and in MPE-derived primary tumor cultures. Morphological examination and image analysis of the tumor spheroids formed in the presence of SCD1 inhibitors showed a different pattern of growth characterized by irregular cell aggregates. Electron microscopy revealed that the treated spheroids displayed several features of cellular damage and immunofluorescence analysis on optical serial sections showed apoptotic cells positive for the M30 marker, most of them positive also for the stemness marker ALDH1A1, thus suggesting that the SCD1 inhibitor is selectively killing cells with stem-like properties. Furthermore, SCD1-inhibited lung cancer cells were strongly impaired in their in vivo tumorigenicity and ALDH1A1 expression. These results suggest that SCD1 is a critical target in lung cancer tumor-initiating cells.

Zebrafish stem cell differentiation stage factors suppress Bcl-xL release and enhance 5-Fu-mediated apoptosis in colon cancer cells

Stem cell differentiation stage factors (SCDSF), taken from Zebrafish embryos during the stage in which totipotent stem cells are differentiating into pluripotent stem cells, have been shown to inhibit proliferation and induce apoptosis in colon tumors. In order to ascertain if these embryonic factors could synergistically/additively interact with 5-Fluorouracil (5-Fu), whole cell-count, flow-cytometry analysis and apoptotic parameters were recorded in human colon cancer cells (Caco2) treated with Zebrafish stem cell differentiation stage factors (SCDSF 3 µg/ml) in association or not with 5-Fu in the sub-pharmacological therapeutic range (0.01 mg/ml). Cell proliferation was significantly reduced by SCDSF, meanwhile SCDSF+5-Fu leads to an almost complete growth-inhibition. SCDSF produces a significant apoptotic effect, meanwhile the association with 5-FU leads to an enhanced additive apoptotic rate at both 24 and 72 hrs. SCDSF alone and in association with 5-Fu trigger both the extrinsic and the intrinsic apoptotic pathways, activating caspase-8, -3 and -7. SCDSF and 5-Fu alone exerted opposite effects on Bax and Bcl-xL proteins, meanwhile SCDSF+5-Fu induced an almost complete suppression of Bcl-xL release and a dramatic increase in the Bax/Bcl-xL ratio. These data suggest that zebrafish embryo factors could improve chemotherapy efficacy by reducing anti-apoptotic proteins involved in drug-resistance processes.

Peripheral blood stem cell collection in multiple myeloma: a retrospective analysis of 6 years leukapheresis activity in 109 patients treated at the Istituto Nazionale dei Tumori of Milan

Double autologous stem cell transplantation is the standard treatment in newly diagnosed multiple myeloma (MM) patients younger than 65 years; therefore, optimization of leukapheresis is crucial. We performed a retrospective analysis of 297 leukaphereses comparing semiautomated (V4.7 in 20% of collections) versus automated (V6.0 in 80%) Caridian (COBE) Spectra versions and analyzing the influence of M-protein on the outcome. Both methods gave comparable collection efficiencies (CE%) (53.4% vs. 55.7% in V6.0 and V4.7, respectively) with similar leukapheresis time and processed volume. Harvest volume was higher in V4.7 (P < 0.0001) with similar contamination of red blood cells (RBCs) (P = 0.77) and platelets (P = 0.09) when compared with V6.0. In patients with higher peripheral white blood cells (WBCs), V6.0 with adjusted harvest volume (<700 mL), achieved similar CD34(+) CE% (P = 0.39) and better enrichment of nucleated cells (P < 0.0,002) but higher RBCs (P < 0.0,001) and platelets contamination (P = 0.001), when compared with a larger cycle volume in patients with lower WBCs. In hard to mobilize patients, CD34(+) CE% was significantly more efficient with V4.7 than V6.0 (P < 0.0,001). CD34(+) CE% was unaffected by serologic M-protein, but platelet CE% was higher in the absence of M-protein (P = 0.0,003), without any reduction in peripheral patients platelets. We, therefore, conclude that in the setting of MM patients with a high WBCs count and/or low percentage of peripheral CD34(+) cells, collections with V4.7 or adjusted cycle volume V6.0 gave comparable result in CD34(+) CE%. RBCs and platelets contamination is higher if low cycle volume is chosen. In hard to mobilize patients, V4.7 is advisable.

Management of poor peripheral blood stem cell mobilization: incidence, predictive factors, alternative strategies and outcome. A retrospective analysis on 2177 patients from three major Italian institutions

CD34+ peripheral blood hematopoietic stem cells (HSC) are usually collected following mobilization therapy accomplished by using growth factors (GF) such as rHuG-CSF or rHuGM-CSF with or without chemotherapy. A target dose of yielded CD34+ is usually prescribed by the attending physician depending on different protocols, which may include single or double transplantation. HSC collection usually is performed when at least 20 CD34+ HSC/microL are detected by means of flow cytometry. A cumulative dose of at least 2 x 10(6)/Kg/bw CD34+ HSC has been considered as the threshold to allow a prompt and persistent hematopoietic recovery. Unfortunately, this goal is not achieved by the totality of patients undergoing mobilization regimen. In fact, 5-46% of patients who underwent mobilization therapy fail HSC collection due to very low peripheral blood HSC CD34+ count. Patients' characteristics, including age, sex, stage of the underlying disease (complete or partial remission), diagnosis, previously administered radio/chemotherapy regimens, time-lapse from last chemotherapy before mobilization and mobilization schedule (including dose of GF) were considered as possibly predictive of poor or failed mobilization. We performed a retrospective analysis in 2177 patients from three large Italian academic institutions to assess the incidence of poor mobilizers within our patients' series. Therefore, a patient who fails a first mobilization (and when an HLA-compatible related on unrelated donor is not available) could undergo a second attempt either with different mobilization schedule or by using different GF, such as stem cell factor, growth hormone (GH), or more recently newly introduced drugs such as AMD3100, alone or in combination with rHuG- or -rHuGM-CSF. Thus, we investigated the fate of those who failed a first mobilization and subsequently underwent a second attempt or alternative therapeutic approaches.

Peripheral blood stem cell collection in pediatric patients: feasibility of leukapheresis under anesthesia in uncompliant small children with solid tumors

Leukapheresis demands patient's compliance and adequate vascular accesses, which can require invasive methods in very small children whose treatment protocol includes hemopoietic stem cell collection for myeloablative chemotherapy and stem cell rescue. Since 1998, at the Istituto Nazionale Tumori of Milan, in selected uncompliant small children, the placement of peripheral vascular accesses and leukapheresis have been performed at the same time under general anesthesia. Peripheral venous cannulas were positioned for blood collection, while blood was returned through either peripheral cannulas or mono-lumen central catheters previously installed for chemotherapy. A continuous-flow cell separator was used for leukapheresis. Between 1998 and 2003, 47 children with solid tumors underwent anesthesia for a total of 54 leukaphereses. The patients' age ranged from 12.7 to 93 months (median 30.3) and their weight ranged from 7 to 20 kg (median 14.1). Neither metabolic nor anesthesiological complications were recorded. In 89% of cases, the CD 34(+) cell target was achieved at a single harvest; the median number of CD 34(+) cells was 10.8 x 10(6)/kg/leukapheresis (range 1-117) and the median collection efficiency was 63.4% (range 25-100.6). Leukapheresis under anesthesia is feasible and safe in very low-weight children whose compliance is lacking due to age and disease.

Dual role of VEGF in pretreated experimental ePTFE arterial grafts

BACKGROUND

Lack of endothelialization and abnormal smooth muscle cell (SMC) growth adversely affect the outcome of vascular synthetic grafts. The aims of our study were to investigate how a coating of extracellular matrix (ECM) and vascular endothelial growth factor (VEGF) might affect the endothelialization rate, smooth muscle cells (SMC) proliferation, and myointimal hyperplasia in experimental arterial ePTFE grafts.

METHODS

In each of 30 male Lewis rats, a 1-cm-long ePTFE graft was inserted at the level of the abdominal aorta. Animals were randomized in five groups (six animals each): groups A and A1 received ePTFE grafts coated with a synthetic extracellular matrix (growth factor-reduced matrigel) containing VEGF; groups B and B1 received ePTFE grafts coated with synthetic ECM; and group C received ePTFE grafts alone. The grafts were explanted at 30 days from surgery for immunohistochemical analysis.

RESULTS

Both endothelialization rate and myointimal hyperplasia were augmented in group A versus groups B and C, and these findings were statistically significant. SMC density resulted significantly higher in group A versus groups B and C, and this was associated with an altered expression of bFGF and TGFbeta.

CONCLUSIONS

Pretreating ePTFE grafts with synthetic ECM and VEGF results in better endothelialization, but also in undesired higher SMC density and myointimal hyperplasia.

Integration between point-of-care cardiac markers in an emergency/cardiology department and the central laboratory: methodological and preliminary clinical evaluation

To achieve rapid assessment of chest pain in emergency/cardiology departments, a short turnaround time for cardiac marker testing is necessary. Nevertheless, Total Quality Management principles must be incorporated into the management of point-of-care testing (POCT); in this setting we implemented the Stratus CS

FLIP is expressed in mouse testis and protects germ cells from apoptosis

Apoptosis control in adult testis is crucial to achieve normal spermatogenesis. In this study c-FLIP, an apoptosis-modulating protein, was investigated. In Western blot and immunohistochemical analyses, the 55 KDa c-FLIP long isoform (c-FLIP(L)) was found to be expressed strongly in spermatocytes and spermatids, at low levels in spermatogonia and at almost undetectable levels in Sertoli cells. This expression pattern was confirmed by Northern blot analyses. Further experiments carried out on GC-1spg germ cell line revealed that reducing c-FLIP(L) expression increases Fas-dependent apoptosis. Conversely, restoring c-FLIP(L) expression reduces this response to control levels. Caspase-10 expression was found to match c-FLIP(L) expression pattern; further, caspase-10 activation upon anti-Fas treatment inversely correlated with c-FLIP(L) expression. Finally, TUNEL staining of seminiferous tubules incubated with anti-Fas antibody showed that apoptosis occurs mostly in basally located germ cells, indicating that such cells, expressing low levels of c-FLIP(L), are sensitive to Fas-mediated apoptosis. These data indicate for the first time that c-FLIP(L) might control germ cell apoptosis and caspase activity in the adult testis.

Bimodal concentration-dependent effect of thrombin on endothelial cell proliferation and growth factor release in culture

BACKGROUND

The role of thrombin in the stimulation of endothelial cell (EC) proliferation is controversial. The aim of this study was to investigate if thrombin regulates cell proliferation and production of platelet-derived growth factor (PDGF), bovine fibroblast growth factor (bFGF), and transforming growth factor beta(1) (TGF-beta(1)) by bovine aortic ECs.

METHODS

ECs, obtained from thoracic aortas of calves, were stimulated with thrombin at various concentrations (from 0.05 to 1.0 IU/ml) in serum free culture. Mitogenic activity of thrombin on ECs was determined by tritiated thymidine uptake. The release of PDGF, bFGF, and TGF-beta(1) was assessed by ELISA. PDGF release was confirmed by Western blot and bFGF and TGF-beta(1) mRNA expression was determined by polymerase chain reaction (PCR).

RESULTS

Thrombin at high concentrations did not cause any increase in EC proliferation after 72 h of culture and induced inhibition of EC proliferation after 96 h and 8 days of culture. It induced a decrease in PDGF release and an increase in TGF-beta(1) release. Thrombin at low concentrations induced a significant increase in EC proliferation at 72 h, 96 h, and 8 days of culture. It induced an increase in PDGF release and a decrease in TGF-beta(1) release. bFGF release was higher than control at all thrombin concentrations. These data were confirmed by Western blot and PCR studies.

CONCLUSIONS

Thrombin regulates EC growth through the inhibition of EC proliferation at high concentrations and through the stimulation of EC proliferation at low physiological concentrations. EC proliferation is partially mediated by autocrine production of PDGF, bFGF, and TGF-beta(1).

Prediction of the extent of coronary artery disease with the evaluation of left ventricular wall motion abnormalities during atrial pacing. A cross-sectional echocardiographic study

In patients with coronary artery disease, left ventricular performance during stress is affected by the degree of coronary stenosis. In order to verify whether there exists a relationship between the extent of wall motion abnormalities detectable during atrial pacing and the degree of coronary obstruction, 76 patients, without previous myocardial infarction, were studied. Each patient underwent cross-sectional echocardiography during transesophageal atrial pacing and exercise electrocardiography before coronary angiography. Of the 76 patients, 46 had significant coronary artery disease (stenosis greater than or equal to 75% of at least one major coronary vessel), while 30 had normal coronaries or a stenosis of less than 75%. Eighteen patients had single-, 14 had two- and 14 had three-vessel disease. For each patient a coronary score was obtained: the score used took into consideration the site, number and severity of the stenosis. This score was then correlated with the wall motion score, obtained from the analysis of 9 segments of the left ventricle. A weak correlation was obtained between wall motion score at rest and coronary score (r = -0.42), while the correlation between coronary score and the difference between wall motion score at rest and during transesophageal atrial pacing was slightly better (r = 0.53); this correlation further improved if wall motion score during pacing was considered (r = -0.63). If the patients with discordant diagnostic tests (echocardiography during transesophageal atrial pacing and exercise electrocardiography) were excluded, the correlation coefficient between coronary score and wall motion score during pacing increased even more (r = -0.77).

IN CONCLUSION

(1) analysis of wall motion of the left ventricle during atrial pacing is useful for the non-invasive evaluation of the severity of coronary disease; (2) cross-sectional echocardiography during atrial pacing, apart from being a useful diagnostic tool, is also a help in judging the degree of severity of coronary artery disease.