Quality control of extracorporeal photochemotherapy: Proliferation assay using CFSE validated according to ISO 15189:2007 standards

Pilot study of a new online extracorporeal photopheresis system in patients with steroid refractory or dependent chronic graft vs host disease

BACKGROUND

A new protocol has been developed on the Amicus Separator that enables the device to perform online extracorporeal photopheresis (ECP) procedures when used in conjunction with the Phelix photoactivation device and associated disposable kit. The objective of this study was to evaluate the safety and performance of the Amicus ECP System in adult subjects with steroid-refractory or dependent chronic graft vs host disease (cGVHD).

STUDY DESIGN AND METHODS

Eight subjects with mild to severe cGVHD underwent 31 procedures. Subject safety evaluations were performed pre and post procedure and adverse events (AEs) were recorded during treatment and 24 hours after the last procedure. In vitro evaluations of the treated cells included hematology counts and lymphocyte apoptosis, viability and proliferation as measures for ECP procedure validation.

RESULTS

For n = 23 evaluable procedures, median (range) procedure time was 88 (78-110) minutes, during which 2.9 (0.6-4.7) × 10⁹ TNCs (approximately 90% MNCs) were treated and reinfused to the subjects. All subject safety evaluations (vitals, cell counts, plasma hemoglobin and bacterial and endotoxin testing) were within expected ranges. All device or procedure related AEs were mild in nature. After 24 hours in culture, 86 (52-98)% of treated lymphocytes were apoptotic compared to 27 (15-51)% in controls. Inhibition of lymphocyte proliferation was >91% in all procedures.

CONCLUSION

ECP procedures were safely completed in adult subjects with SR-cGVHD treated using the new online Amicus ECP system.

CD71 surface analysis of T cells: a simple alternative for extracorporeal photopheresis quality control

BACKGROUND

Extracorporeal photopheresis (ECP) is a leukapheresis-based cellular therapy that is used with increasing frequency worldwide to treat various T-cell-mediated diseases. Currently, the inhibition of T-cell proliferation after photopheresis is analysed frequently using time-consuming assays including radioactive thymidine assays or carboxyfluorescein succinimidyl ester (CFSE) staining. We investigated whether simple surface T-cell staining using surrogate markers of T-cell proliferation can replace time-consuming measurement of T-cell proliferation in ECP quality control.

STUDY DESIGN AND METHODS

T-cell activation markers were investigated by flow cytometry after ECP. Candidates were validated by direct comparison with the classical CFSE T-cell proliferation inhibition test and apoptosis staining. Finally, surface T-cell staining was performed in patient samples in comparison with classical methods.

RESULTS

CD71 expression exhibited the fastest and most robust upregulation, which was detectable as early as 6-8 h after T-cell stimulation and almost completely abrogated by ECP. In a direct comparison with the CFSE T-cell proliferation assay, suppression of CD71 expression after ECP was almost identical and detectable as early as 16 h after stimulation in peripheral blood mononuclear cells of healthy donors. Furthermore, in direct comparison with classical apoptosis staining, the inhibition delta of CD71 after ECP was significantly higher. Moreover, in patients under T-cell suppressive therapy, T-cell-dependent CFSE and CD71 assays exhibited decreased sensitivity to detect ECP treatment and were inferior in comparison to apoptosis staining.

CONCLUSION

Surface CD71 analysis represents a very simple quality control alternative to detect ECP-mediated T-cell proliferation inhibition in normal PBMC samples devoid of T-cell suppressive drugs.

In vitro T lymphocyte proliferation by carboxyfluorescein diacetate succinimidyl ester method is helpful in diagnosing and managing primary immunodeficiencies

BACKGROUND

Functional studies besides routine laboratory tests for the definitive diagnosis of T lymphocyte disorders with isolated T or combined T/B-cell immunodeficiencies are important. We hereby summarized our experience with a carboxyfluorescein diacetate succinimidyl ester (CFSE)-based assay for the assessment of mitogenic T-cell proliferation responses in primary immunodeficiency (PID) patients who have not been diagnosed yet or genetically analyzed, but classified as probably having T-cell defects.

METHODS

Unclassified patients (n=46) and controls (n=25) were evaluated for T-cell disorders with CFSE-based assay.

RESULTS

CD3⁺ blast cells after PHA-L stimulation were significantly lower in patients (31.1±28.8) than controls (67.9±8.79; P<.001). Nine patients with low and four patients with normal CD3 values had severely decreased blastic transformation. The proliferation response decreased mostly in combined immunodeficiency group. Sixteen of them had impaired proliferation responses. Appropriate molecular genetical analyses were planned after thorough evaluation of each patient.

CONCLUSIONS

In vitro lymphocyte cell proliferation analysis by CFSE method is a reliable and practical choice for the assessment of mitogenic T lymphocyte responses in yet unclassified PID patients for targeting further genetical analyses.

A concise review on extracorporeal photochemotherapy: Where we began and where we are now and where are we going!

Currently, more than 1080 peer-reviewed papers are displayed on PubMed when initiating a search for therapeutic indications and mechanisms of action of extracorporeal photochemotherapy (ECP). This concise review focuses mainly on some prevalent and traditional treatment-resistant disorders with an emphasis on immunologic complications emerging from stem cell and solid organ transplantation.