T-TAS® 01 as a new tool for the evaluation of hemostasis in thrombocytopenic patients after platelet transfusion

BACKGROUND

Current laboratory tests fail to evaluate the hemostatic function of platelets in patients with thrombocytopenia. We investigated the use of the Total Thrombus-Formation Analysis System (T-TAS® 01 [Fujimori Kogyo Co, Tokyo, Japan]) to evaluate hemostasis under conditions of experimental thrombocytopenia, and in patients before and after platelet transfusion.

MATERIALS AND METHODS

Specific T-TAS 01 chips, for thrombocytopenic conditions, were used. The area under the curve (AUC) and occlusion time (OT, min) were measured in: (i) experimentally induced thrombocytopenia (183±15 to 6.3±1.2×103 platelets/μL) in blood samples from healthy donors (No.=13), and (ii) blood from oncohematological thrombocytopenic patients (No.=48), before and after platelet transfusion. The influences of hematocrit and number of transfusions were analyzed in these patients.

RESULTS

Progressive reductions of AUC and prolongations of OT related significantly to decreasing platelet counts (p<0.05 for all) in experimental thrombocytopenia. In samples from thrombocytopenic patients, platelet counts, AUC and OT were, respectively, 10.8±0.6×103/μL, 175.2±59, and 27.2±1 min before transfusion; and 22±1.5×103/μL, 400.8±83 and 22.9±1.5 min after platelet transfusion (p<0.01 for all). A hematocrit below 25% or exposure to ten or more previous platelet transfusions had a negative impact on the T-TAS 01 performance in patients. In vitro correction of the hematocrit improved the hemostatic response in thrombocytopenic patients.

DISCUSSION

T-TAS 01 measurements were sensitive to low platelet counts in the experimental setting. The technology was sensitive to evaluate the hemostatic capacity of platelet transfusions. Exposure to multiple medications, repeated platelet transfusions and lower hematocrits may interfere with the hemostatic performance in oncohematological patients with thrombocytopenia.

Evaluation of cell collection efficiency in non-mobilized adult donors for autologous chimeric antigen receptor T-cell manufacturing

BACKGROUND AND OBJECTIVES

Data about collection efficiency 1 (CE1), which takes into account blood cell counts before and after collection, thus providing a more accurate estimate, in the collection of autologous T lymphocytes by apheresis for chimeric antigen receptor (CAR) T-cells remain scarce. We evaluated donor- and procedure-related characteristics that might influence the CE1 of lymphocytes.

MATERIALS AND METHODS

We retrospectively reviewed all mononuclear cell (MNC) collections) performed for CAR T-cell manufacturing in our institution from May 2017 to June 2021 in adult patients. Age, gender, weight, total blood volume (TBV), prior haematopoietic cell transplant, diagnosis, days between last treatment and apheresis, pre-collection cell counts, duration of apheresis, TBV processed, vascular access, inlet flow and device type were analysed as potential factors affecting CE1 of lymphocytes.

RESULTS

A total of 127 autologous MNC collections were performed on 118 patients diagnosed with acute lymphoblastic leukaemia (n = 53, 45%), non-Hodgkin lymphoma (n = 40, 34%), multiple myeloma (n = 19, 16%), and chronic lymphocytic leukaemia (n = 6, 5%). The median CE1 of lymphocytes was 47% (interquartile range: 32%-65%). In multiple regression analysis, Amicus device was associated with higher CE1 of lymphocytes (p = 0.01) and lower CE1 of platelets (p < 0.01) when compared with Optia device.

CONCLUSION

The knowledge of the MNC and lymphocyte CE1 of each apheresis device used to collect cells for CAR T therapy, together with the goal of the number of cells required, is essential to define the volume to be processed and to ensure the success of the collection.

Get Off on the Right Foot: How to Plan an Efficient Leukocytapheresis to Collect T Cells for CAR T-Cell Manufacturing

<b><i>Background:</i></b> The major drug regulatory agencies have approved chimeric antigen receptor (CAR) T cells for the treatment of some B-cell lymphoproliferative diseases. Their use is expanding, and new indications will be approved. Efficient mononuclear cell collection by apheresis providing enough T cells is a critical step in further CAR T-cell manufacturing process. It is important that apheresis units are prepared for the collection of the required T cells for manufacturing with the highest efficiency and safety for the patient. <b><i>Summary:</i></b> Several series have studied different characteristics that could influence the collection efficiency of T cells for CAR T-cell manufacturing. Also, an effort has been made to identify predictors of the total number of target cells collected. Despite these publications and the large number of ongoing clinical trials, consensus protocols in apheresis are scarce. <b><i>Key Messages:</i></b> The aim of this review was to summarize the set of measures described to optimize apheresis and ensure patient safety. Moreover, we also propose, in a practical approach, a way to apply this knowledge to the daily routine in the apheresis unit.

Serum soluble CD23 levels are an independent predictor of time to first treatment in chronic lymphocytic leukemia

Serum soluble CD23 (sCD23) levels have been acknowledged as a prognostic factor in patients with chronic lymphocytic leukemia (CLL), but their potential relevance has not been analyzed in recent times. We retrospectively studied 338 CLL, small lymphocytic lymphoma, or CLL-type monoclonal B-cell lymphocytosis patients from a single institution, with available sCD23 levels at diagnosis. Baseline features and outcomes were compared between patients with sCD23 ≤/>1000 UI/L. The 140 patients (41%) who had sCD23 > 1000 UI/L showed adverse-risk clinical and biological characteristics. High sCD23 levels were predictive of a shorter time to first treatment (5-year probability of requiring treatment: 60 vs. 20%, p < 0.0001; hazard ratio (HR) = 1.72, p = 0.003 in a multivariable model also including the CLL International Prognostic Index and the absolute lymphocyte count), and a poorer 5-year overall survival (70 vs. 82%, p = 0.0009). These data suggest the potential of sCD23 to predict treatment-free survival and to shed light on mechanisms of activity and resistance to CD23-directed therapies.

Baseline correlations and prognostic impact of serum monoclonal proteins in follicular lymphoma

The presence of a serum monoclonal component has been associated with poor outcomes in some lymphomas. However, data in follicular lymphoma (FL) are scarce. We studied 311 FL patients diagnosed at a single institution, for whom information on serum immunofixation electrophoresis (sIFE) at diagnosis was available. Baseline characteristics and outcomes were compared between patients with a positive (+sIFE) and a negative sIFE (-sIFE). sIFE was positive in 82 patients (26%). Baseline features were comparable between both groups, except for an older age and higher proportion of elevated β₂ -microglobulin levels in the +sIFE group. With a median follow-up of 4.6 years, a +sIFE was associated with a higher risk of early relapse (POD24, 27% vs. 15%, P = 0·02), shorter progression-free survival (PFS; 42% vs. 52% at 5 years, P = 0·008), and shorter overall survival (OS; 59% vs. 77% at 10 years, P = 0·046). In patients >60 years, a +sIFE was an independent predictor of OS [hazard ratio (HR) = 2·4, 95% confidence interval (CI): 1·2-5·0; P = 0·02]. Approximately one quarter of patients with FL has a +sIFE at diagnosis, which is a predictor of poor outcome. These findings encourage further investigation of its relationship with B-cell biology and the tumour microenvironment.