Apoptosis induction by extracorporeal photopheresis is enhanced by increasing the 8‐methoxypsoralen concentration and by replacing plasma with saline

Abstract

Background: Extracorporeal photopheresis (ECP), an apheresis-based therapy for various immunological diseases, works mainly by inducing apoptosis in lymphocytes. Several factors influence the efficacy of ECP with the photosensitizer 8-methoxypsoralen (8-MOP) and ultraviolet light A (UVA). This study aimed to optimize treatment by varying the 8-MOP starting concentration and the cell suspension medium. Materials and Methods: All patients (n = 13) included in this study received photopheresis as medically indicated. Cells collected with a Spectra Optia apheresis system were suspended in plasma or physiological saline (NaCl) and incubated with 200 ng/ml versus 340 ng/ml photosensitizer before UVA irradiation (Macogenic G2 or UVA PIT system). Lymphocyte apoptosis and caspase activity were analyzed by flow cytometry and fluorimetry, and residual 8-methoxypsoralen concentrations by liquid chromatography-mass spectrometry.Results: Raising the 8-MOP starting concentration significantly increased lymphocyte apoptosis, with values of 22% versus 35% (plasma) and 28%-46% (NaCl) at 24 h post-ECP and 37% versus 86% (plasma) and 74% versus 97% (NaCl) at 48 h for 200 ng/ml versus 340 ng/ml. Pre-transfusion residual 8-MOP levels were 168 ng/ml (plasma) and 162 ng/ml (NaCl) versus 290 ng/ml (plasma) and 266 ng/ml (NaCl) for the lower versus higher dose, respectively. Discussion: Hence, 8-MOP concentration influences the efficacy of photopheresis as lymphocyte apoptosis rates were significantly higher with the higher starting concentration and with NaCl versus plasma. This indicates that

What Does the Future Hold for Biomarkers of Response to Extracorporeal Photopheresis for Mycosis Fungoides and Sézary Syndrome?

“…A small percentage of lymphocytes collected ex vivo show signs of apoptosis almost immediately following the exposure to 8-MOP and UVA; the formation of monoadducts and covalent crosslinks of DNA causes morphological changes including the externalization of phosphatidylserine residues and the reversal of the Bax/Bcl-2 ratio [ 1 , 44 , 49 , 55 , 56 , 57 , 58 , 59 ]. Following this, a second late-stage apoptosis begins, characterized by the upregulation of the tumor suppressor gene p53 and the modulation of Fas/FasL signaling which induces the activation-induced cell death (AICD) pathway [ 50 ].…”

Xanthotoxin (8‐methoxypsoralen): A review of its chemistry, pharmacology, pharmacokinetics, and toxicity

“…In clinical practice, we use 8-MOP at a concentration of about 2.6 mg/L, the wavelength of UVA is 325 nm (Al-Ismail, Edwards, & Anstey, 2016). 8-MOP inhibits epidermal thickening (Alalaiwe et al, 2018), ragging (Hayashi, Ikeda, Kitamura, Hamasaki, & Hatamochi, 2012), and wrinkles (Zhou et al, 2020), upregulated the level of P16, a channel protein associated with aging, and down regulates the level of miR27a and 29a (Shirsath et al, 2018;Singh, Schn, Wallbrecht, & Wolf, 2012;Tatsuno, Hanlon, Yamazaki, Galluzzi, & Edelson, 2019), thereby inhibiting the secretion of interferon-gamma (IL-γ), In addition, the development of psoriasis is also related to the immune system (Trautinger, 2018), and PUVA is often used in combination with immunosuppressive columns such as methicillin to improve the efficacy (Jagasia et al, 2019), and Extracorporeal photopheresis (ECP) is immunotherapy mainly used to inhibit dendritic cells (DCs) maturation (Failli et al, 2011), induce apoptosis (Hahnel et al, 2021), and regulate the function of T lymphocytes and B lymphocytes (Futterleib, Feng, Tigelaar, Choi, & Edelson, 2014;Wei, Sun, Xiao, & Shi, 2018). The core of ECP lies in the induction of immune tolerance and enhanced cytotoxicity through apoptosis of the patient's leukocytes (Budde, Berntsch, Riggert, & Legler, 2017;Holien, Gederaas, Darvekar, Christensen, & Peng, 2018).…”

“…In addition, the development of psoriasis is also related to the immune system (Trautinger, 2018), and PUVA is often used in combination with immunosuppressive columns such as methicillin to improve the efficacy (Jagasia et al, 2019), and Extracorporeal photopheresis (ECP) is immunotherapy mainly used to inhibit dendritic cells (DCs) maturation (Failli et al, 2011), induce apoptosis (Hahnel et al, 2021), and regulate the function of T lymphocytes and B lymphocytes (Futterleib, Feng, Tigelaar, Choi, & Edelson, 2014; Wei, Sun, Xiao, & Shi, 2018). The core of ECP lies in the induction of immune tolerance and enhanced cytotoxicity through apoptosis of the patient's leukocytes (Budde, Berntsch, Riggert, & Legler, 2017; Holien, Gederaas, Darvekar, Christensen, & Peng, 2018).…”

Pharmacotherapy of chronic lung allograft dysfunction post lung transplantation

“…Extracorporeal photopheresis (ECP) is a procedure performed with the photoactive drug 8‐methoxypsoralen (8‐MOP) that requires removal of a fraction of a patient's blood and isolation of leukocytes that are exposed to ultraviolet light. The leukocytes are then returned to the patient resulting in leukocyte apoptosis and induction of regulatory T cells 63 . The mechanism by which ECP works in the setting of CLAD is not well understood, but may be associated with a decrease or stability in donor specific antibodies (DSAs) and reduction in inflammatory cytokines 2 .…”

“…The leukocytes are then returned to the patient resulting in leukocyte apoptosis and induction of regulatory T cells. 63 The mechanism by which ECP works in the setting of CLAD is not well understood, but may be associated with a decrease or stability in donor specific antibodies (DSAs) and reduction in inflammatory cytokines. study was underpowered to detect any meaningful differences in this regard.…”