A simplified extracorporeal photopheresis procedure based on single high‐dose ultraviolet A light irradiation shows similar in vitro efficacy. Issue 3 (10th December 2020)

• Record Type: Journal Article
• Authors: Buchele, Vera; Hackstein, Holger
• Is Part Of: Transfusion. Volume 61:Issue 3(2021)
• Page Start: 883
• Page End: 893
• Publication Date: 2020-12-10
• Subjects: apoptosis -- extracorporeal photopheresis -- UVA light; Hematology -- Periodicals; Blood -- Transfusion -- Periodicals; Blood Group Antigens -- Periodicals; Blood Preservation -- Periodicals; Blood Transfusion -- Periodicals; 615
• DOI: 10.1111/trf.16209
• Languages: English
• ISSNs: 0041-1132

Abstract

Abstract: Background: Extracorporeal photopheresis (ECP) is one of the most widely used and effective cell‐based therapies for the treatment of T‐cell–mediated diseases. The patients' white blood cells (WBCs) are collected by apheresis and exposed to the photosensitizer 8‐methoxypsoralen (8‐MOP) and ultraviolet A (UVA) light before retransfusion. The UVA/8‐MOP combination has been in use in ECP for more than 4 decades; however, whether ECP can be simplified by UVA light irradiation only has never been analyzed. Study Design and Methods: Peripheral blood mononuclear cells were treated with classical ECP or different UVA light doses only (UVA only ). Treatment efficacy was investigated by apoptosis induction in WBC subsets, inhibition of T‐cell proliferation, and the ability of monocytes to induce allogeneic T‐cell expansion and to respond to lipopolysaccharide and interferon‐γ stimulation in vitro. Results: High‐dose UVA only treatment (5 J/cm 2 ) was as efficient as ECP to induce apoptosis within 48 hours. UVA only treatment modulated the composition of the surviving cells by improving monocyte survival and promoting CD8 + T‐cell apoptosis. Both ECP and UVA only treatment inhibited anti‐CD3/anti‐CD28 triggered T‐cell proliferation. Interestingly, whereas ECP‐treated monocytes exhibited a markedly reduced capacity to respond to stimulation and to induce allogeneic T‐cell proliferation, UVA only treatment preserved monocyte functionality to some degree. Conclusions: High‐dose UVA only and standard ECP showed comparable efficacy in inducing apoptosis and inhibiting direct T‐cell proliferation. Hence, UVA only treatment can be a simplified alternative to ECP therapy. Furthermore, increased monocyte survival with partially preserved functionality after UVA only treatment may provide a novel method for immunoregulation.